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• 1. [Article] Optimal irrigation management : a framework, model, and application for optimizing irrigation when supplies are limited

  Many regions in North America are experiencing water shortages, and these conditions are expected to worsen. The next generation of irrigation scheduling applications must therefore be capable of providing ...

  Citation × Citation Citation Abstract Copy Title: Optimal irrigation management : a framework, model, and application for optimizing irrigation when supplies are limited Author: Hillyer, Charles C. (Charles Carter) Many regions in North America are experiencing water shortages, and these conditions are expected to worsen. The next generation of irrigation scheduling applications must therefore be capable of providing operational advice in support of deficit irrigation strategies. However, the theoretical, technical, and practical challenges associated with deficit irrigation scheduling are far more complex than conventional (full) irrigation. This dissertation presents three distinct systems for addressing the analytical challenges of deficit irrigation management. The first section of the dissertation presents a simulation framework for agro-ecological simulation. The objective was to develop a method to enable the assembly of simulation models from previously and independently developed component models. Based on a requirements analysis of existing simulation models we developed the ModCom simulation framework. ModCom provides a set of interface specifications that describe components in a simulation. ModCom also provides implementations of the core simulation services. The framework interfaces use well-defined binary standards and allows developers to implement the interfaces using a broad range of computer languages. The Second section describes the Irrigation Efficiency Model (IEM). IEM explicitly analyzes irrigation efficiency, accounts for spatial variability of soil properties and irrigation uniformity, performs simultaneous scheduling for all fields in the farm, accounts for energy use and its associated costs, and uses both ET and soil moisture measurements to enhance the accuracy of the irrigation schedules. IEM was developed specifically for implementing Deficit Irrigation and therefore includes analyses that go beyond the requirements of conventional irrigation scheduling. The third section describes Irrigation Management Online (IMO), a web application for optimum irrigation management. This system uses IEM to generate and deliver irrigation scheduling recommendations. IMO has been developed specifically to support irrigation management when either water supplies or delivery system capacities are limited. To mitigate the complexities of irrigation constraints the system has been designed so that the irrigation manager is an integral part of the irrigation optimization procedure. The final section outlines some of the key challenges that the next generation of schedulers must overcome in order to meet the needs of agricultural irrigation in an increasingly water short future. In addition, this section will discuss how irrigation advisory programs will need to operate differently in terms of what they do and how they do it. Title: Optimal irrigation management : a framework, model, and application for optimizing irrigation when supplies are limited Author: Hillyer, Charles C. (Charles Carter) Many regions in North America are experiencing water shortages, and these conditions are expected to worsen. The next generation of irrigation scheduling applications must therefore be capable of providing operational advice in support of deficit irrigation strategies. However, the theoretical, technical, and practical challenges associated with deficit irrigation scheduling are far more complex than conventional (full) irrigation. This dissertation presents three distinct systems for addressing the analytical challenges of deficit irrigation management. The first section of the dissertation presents a simulation framework for agro-ecological simulation. The objective was to develop a method to enable the assembly of simulation models from previously and independently developed component models. Based on a requirements analysis of existing simulation models we developed the ModCom simulation framework. ModCom provides a set of interface specifications that describe components in a simulation. ModCom also provides implementations of the core simulation services. The framework interfaces use well-defined binary standards and allows developers to implement the interfaces using a broad range of computer languages. The Second section describes the Irrigation Efficiency Model (IEM). IEM explicitly analyzes irrigation efficiency, accounts for spatial variability of soil properties and irrigation uniformity, performs simultaneous scheduling for all fields in the farm, accounts for energy use and its associated costs, and uses both ET and soil moisture measurements to enhance the accuracy of the irrigation schedules. IEM was developed specifically for implementing Deficit Irrigation and therefore includes analyses that go beyond the requirements of conventional irrigation scheduling. The third section describes Irrigation Management Online (IMO), a web application for optimum irrigation management. This system uses IEM to generate and deliver irrigation scheduling recommendations. IMO has been developed specifically to support irrigation management when either water supplies or delivery system capacities are limited. To mitigate the complexities of irrigation constraints the system has been designed so that the irrigation manager is an integral part of the irrigation optimization procedure. The final section outlines some of the key challenges that the next generation of schedulers must overcome in order to meet the needs of agricultural irrigation in an increasingly water short future. In addition, this section will discuss how irrigation advisory programs will need to operate differently in terms of what they do and how they do it. Close

• 2. [Article] Characterizing hydraulics and water distribution of furrow irrigation in northeast Malheur County

  Furrow irrigation is the dominant practice for irrigating row crops in the western Treasure Valley region near Ontario, Oregon. Though improvements have been made in management practices over the years, ...

  Citation × Citation Citation Abstract Copy Title: Characterizing hydraulics and water distribution of furrow irrigation in northeast Malheur County Author: Mittelstadt, Robert Furrow irrigation is the dominant practice for irrigating row crops in the western Treasure Valley region near Ontario, Oregon. Though improvements have been made in management practices over the years, excessive runoff and deep percolation are still important problems contributing to surface water and groundwater degradation. Field observations were made during two growing seasons to establish a data base from which the hydraulic surface irrigation model, SRFR (SRFR, a computer program for simulating flow in surface irrigation, developed at the U.S. Water Conservation Laboratory in Phoenix, Arizona (Strelkoff, 1991)), could be calibrated. SRFR is a numerical model, based on the principles of open channel hydraulics coupled with an empirical relationship characterizing furrow intake. SRFR is an analytical tool, with which the user supplies the physical parameters (such as furrow shape and furrow intake) and also the management variables (inflow rate and duration of inflow), and a simulation is conducted based on these conditions. Therefore, this model is a tool which provides insight into furrow irrigation processes. More specifically, SRFR can help answer such questions as which factors at the time of the irrigation are most important in determining irrigation performance. Once calibrated for a given set of conditions, various management strategies may be evaluated as to their relative effectiveness. These strategies may include, but are not limited to, cut-back irrigation, surge irrigation, alternating furrow irrigation, and laser-leveling of the field. A broad data-base is necessary for model calibration and to develop an understanding of it's limitations. Measurements of furrow intake, stream advance times, inflow and outflow, hydraulic roughness and furrow shape were obtained from several sites and irrigation events. These sites represent several crops, field lengths, field slopes, and soil textures. Using these data, a model calibration procedure was developed which matched irrigation inflow and outflow volumes and stream advance times for a given irrigation event. The calibration procedure is used to help identify those model input parameters that best describe a given irrigation event. This thesis is to provide a broad understanding of furrow irrigation systems in northeast Malheur County, recommended hydraulic parameters for use with SRFR, and the practical limitations of such hydraulic irrigation models. Irrigation performance is largely determined by the intake characteristics of the soil at the time of irrigation. Field conditions vary greatly depending on the crop, soil moisture, number of irrigations, tractor traffic, field slope, furrow shape and field history. The grower has control over only two variables which determine irrigation performance: inflow rate and duration. A difference in intake and irrigation performance was found to exist between non-wheel and wheel traffic furrows. These differences became less noticeable late in the season. Straw mulching greatly increases the furrow hydraulic roughness and therefore increases stream wetted perimeter and advance time. Vegetative interference from crops such as potato and sugar beets increase furrow hydraulic roughness late in the season. Initially, furrow shape depends on the crop and which cultivating implement is used. Furrow shape may evolve during the growing season depending on field slope, flow velocities, crop stand and the presence of crop residues and straw mulch. Title: Characterizing hydraulics and water distribution of furrow irrigation in northeast Malheur County Author: Mittelstadt, Robert Furrow irrigation is the dominant practice for irrigating row crops in the western Treasure Valley region near Ontario, Oregon. Though improvements have been made in management practices over the years, excessive runoff and deep percolation are still important problems contributing to surface water and groundwater degradation. Field observations were made during two growing seasons to establish a data base from which the hydraulic surface irrigation model, SRFR (SRFR, a computer program for simulating flow in surface irrigation, developed at the U.S. Water Conservation Laboratory in Phoenix, Arizona (Strelkoff, 1991)), could be calibrated. SRFR is a numerical model, based on the principles of open channel hydraulics coupled with an empirical relationship characterizing furrow intake. SRFR is an analytical tool, with which the user supplies the physical parameters (such as furrow shape and furrow intake) and also the management variables (inflow rate and duration of inflow), and a simulation is conducted based on these conditions. Therefore, this model is a tool which provides insight into furrow irrigation processes. More specifically, SRFR can help answer such questions as which factors at the time of the irrigation are most important in determining irrigation performance. Once calibrated for a given set of conditions, various management strategies may be evaluated as to their relative effectiveness. These strategies may include, but are not limited to, cut-back irrigation, surge irrigation, alternating furrow irrigation, and laser-leveling of the field. A broad data-base is necessary for model calibration and to develop an understanding of it's limitations. Measurements of furrow intake, stream advance times, inflow and outflow, hydraulic roughness and furrow shape were obtained from several sites and irrigation events. These sites represent several crops, field lengths, field slopes, and soil textures. Using these data, a model calibration procedure was developed which matched irrigation inflow and outflow volumes and stream advance times for a given irrigation event. The calibration procedure is used to help identify those model input parameters that best describe a given irrigation event. This thesis is to provide a broad understanding of furrow irrigation systems in northeast Malheur County, recommended hydraulic parameters for use with SRFR, and the practical limitations of such hydraulic irrigation models. Irrigation performance is largely determined by the intake characteristics of the soil at the time of irrigation. Field conditions vary greatly depending on the crop, soil moisture, number of irrigations, tractor traffic, field slope, furrow shape and field history. The grower has control over only two variables which determine irrigation performance: inflow rate and duration. A difference in intake and irrigation performance was found to exist between non-wheel and wheel traffic furrows. These differences became less noticeable late in the season. Straw mulching greatly increases the furrow hydraulic roughness and therefore increases stream wetted perimeter and advance time. Vegetative interference from crops such as potato and sugar beets increase furrow hydraulic roughness late in the season. Initially, furrow shape depends on the crop and which cultivating implement is used. Furrow shape may evolve during the growing season depending on field slope, flow velocities, crop stand and the presence of crop residues and straw mulch. Close

• 3. [Article] A computer model to simulate farm irrigation system energy requirements

  The development of the energy crisis has caused the use of depletable energy resources to be monitored quite closely in the United States. Within the agricultural sector, irrigation is a large user of ...

  Citation × Citation Citation Abstract Copy Title: A computer model to simulate farm irrigation system energy requirements Author: Kizer, Michael A. The development of the energy crisis has caused the use of depletable energy resources to be monitored quite closely in the United States. Within the agricultural sector, irrigation is a large user of energy, with the potential of using many times more energy than all other agricultural field operations. A better understanding of how energy is used by different irrigation systems could facilitate more efficient use of energy by one of the largest energy consumers in agriculture. This thesis attempts to realistically evaluate the total amount of non-renewable energy resources consumed in the irrigation process. Five portable and permanent sprinkler system types, plus trickle and gravity irrigation systems were studied. An evaluation of the energy required to manufacture the equipment, install it in the field, operate it, and transport it for an entire irrigation season was made. This evaluation was carried out in a variety of operating situations, with varying acreages, consumptive use rates, and total irrigation requirements. The paper begins by giving some background information about agriculture and irrigation as consumers of energy. A review of some of the research previously done which relates to energy use in irrigation is given. The evaluation of energy use by irrigation systems presented in this thesis were made with the use of a simulation model which was developed on the Oregon State University OS-3 Computer System. The model predicts energy requirements of an irrigation system by evaluating pumping energy requirements with basic hydraulic equations, the manufacturing energy requirements by calculating the required amounts of basic materials making up the system and the energy of manufacture of those basic materials. The energy for installation and the energy for transportation were evaluated by simulating methods of operation and management used in Oregon. The input parameters used in the modeling process. reproduce as closely as possible operating conditions encountered in Oregon. System types, component depreciation life, irrigation efficiencies and the range of irrigation requirements are ones that could typically be found in Oregon. For the situations considered, it was concluded that gravity irrigation required much less energy than other system types. The energy requirement for drip systems was about midway between the energy requirement for gravity systems and for sprinkler systems for most cases considered. The relative order of energy requirements for the various sprinkler systems was dependent upon the operating conditions considered. Title: A computer model to simulate farm irrigation system energy requirements Author: Kizer, Michael A. The development of the energy crisis has caused the use of depletable energy resources to be monitored quite closely in the United States. Within the agricultural sector, irrigation is a large user of energy, with the potential of using many times more energy than all other agricultural field operations. A better understanding of how energy is used by different irrigation systems could facilitate more efficient use of energy by one of the largest energy consumers in agriculture. This thesis attempts to realistically evaluate the total amount of non-renewable energy resources consumed in the irrigation process. Five portable and permanent sprinkler system types, plus trickle and gravity irrigation systems were studied. An evaluation of the energy required to manufacture the equipment, install it in the field, operate it, and transport it for an entire irrigation season was made. This evaluation was carried out in a variety of operating situations, with varying acreages, consumptive use rates, and total irrigation requirements. The paper begins by giving some background information about agriculture and irrigation as consumers of energy. A review of some of the research previously done which relates to energy use in irrigation is given. The evaluation of energy use by irrigation systems presented in this thesis were made with the use of a simulation model which was developed on the Oregon State University OS-3 Computer System. The model predicts energy requirements of an irrigation system by evaluating pumping energy requirements with basic hydraulic equations, the manufacturing energy requirements by calculating the required amounts of basic materials making up the system and the energy of manufacture of those basic materials. The energy for installation and the energy for transportation were evaluated by simulating methods of operation and management used in Oregon. The input parameters used in the modeling process. reproduce as closely as possible operating conditions encountered in Oregon. System types, component depreciation life, irrigation efficiencies and the range of irrigation requirements are ones that could typically be found in Oregon. For the situations considered, it was concluded that gravity irrigation required much less energy than other system types. The energy requirement for drip systems was about midway between the energy requirement for gravity systems and for sprinkler systems for most cases considered. The relative order of energy requirements for the various sprinkler systems was dependent upon the operating conditions considered. Close

• 4. [Article] Basin-wide distributed modeling of hydrologic responses to irrigation management in the Wood River Basin, Klamath County, OR

  The Wood River Basin lies upstream of Upper Klamath Lake, the main reservoir of the USBR Klamath Irrigation Project that provides irrigation water to 210,000 acres of downstream land. Water allocation ...

  Citation × Citation Citation Abstract Copy Title: Basin-wide distributed modeling of hydrologic responses to irrigation management in the Wood River Basin, Klamath County, OR Author: Owens, Joshua M. The Wood River Basin lies upstream of Upper Klamath Lake, the main reservoir of the USBR Klamath Irrigation Project that provides irrigation water to 210,000 acres of downstream land. Water allocation became a contentious issue in 2001 when drought led to curtailment of irrigation deliveries to the Klamath Irrigation Project in order to maintain minimum lake levels and river flows for endangered species. After lengthy negotiations the Klamath Basin Restoration Agreement was signed in February 2010, and calls for flow increases of 30,000 ac-ft/yr into Upper Klamath Lake from voluntary upstream sources. The Wood River Basin is a potential source of this water, but poorly understood hydrology makes estimates of water gains in response to conservation strategies uncertain. To better understand the hydrology of the Wood River Basin a fully distributed, physically based model was set up using the MIKE SHE hydrology model and MIKE 11 hydraulic model by DHI, Inc. The model was developed by recreating the actual management of the basin from 2002 to 2009, a period when tracts of land in the basin were enrolled in land idling programs for water conservation. Calibration and validation was evaluated against shallow groundwater observations. Overall the model described the average conditions of the basin well. Locations that were simulated inaccurately were limited to those in close proximity to the model boundary or to the Wood River, the result of using average values to describe these heterogeneous features. The model was used to simulate two end-member scenarios to determine the limits of water conservation strategies, basin-wide full irrigation and non-irrigation. Two reduced irrigation scenarios were also simulated, the first reduced the irrigation season to June and July, the second eliminated every other irrigation application. The simulation that recreated the actual management showed that non-irrigated tracts did not substantially reduce the consumptive use because water from the surrounding irrigated tracts was able to flow in via the shallow aquifer and provide sub-irrigation. For the full irrigation scenario the average annual consumptive use was 126,000 ac-ft/yr. For the non-irrigated scenario it was 96,000 ac-ft/yr, a reduction of 24%. For the two reduced irrigation scenarios the consumptive use was decreased by 14% and 12%. When compared to the irrigated scenario the total increase of flow to Upper Klamath Lake during the growing season was 60,000 ac-ft/yr for the non-irrigated scenario; and 36,000 ac-ft/yr and 31,000 ac-ft/yr for the two reduced irrigation scenarios respectively. Irrigation in the basin was found to transfer stream flow from the summer time to the winter time due to saturated winter conditions from late season irrigations resulting in increased runoff. There is potential for water conservation strategies in the Wood River Basin to substantially increase water flow into Upper Klamath Lake, but these strategies would have to be implemented extensively throughout the basin to reduce sub-irrigation. Title: Basin-wide distributed modeling of hydrologic responses to irrigation management in the Wood River Basin, Klamath County, OR Author: Owens, Joshua M. The Wood River Basin lies upstream of Upper Klamath Lake, the main reservoir of the USBR Klamath Irrigation Project that provides irrigation water to 210,000 acres of downstream land. Water allocation became a contentious issue in 2001 when drought led to curtailment of irrigation deliveries to the Klamath Irrigation Project in order to maintain minimum lake levels and river flows for endangered species. After lengthy negotiations the Klamath Basin Restoration Agreement was signed in February 2010, and calls for flow increases of 30,000 ac-ft/yr into Upper Klamath Lake from voluntary upstream sources. The Wood River Basin is a potential source of this water, but poorly understood hydrology makes estimates of water gains in response to conservation strategies uncertain. To better understand the hydrology of the Wood River Basin a fully distributed, physically based model was set up using the MIKE SHE hydrology model and MIKE 11 hydraulic model by DHI, Inc. The model was developed by recreating the actual management of the basin from 2002 to 2009, a period when tracts of land in the basin were enrolled in land idling programs for water conservation. Calibration and validation was evaluated against shallow groundwater observations. Overall the model described the average conditions of the basin well. Locations that were simulated inaccurately were limited to those in close proximity to the model boundary or to the Wood River, the result of using average values to describe these heterogeneous features. The model was used to simulate two end-member scenarios to determine the limits of water conservation strategies, basin-wide full irrigation and non-irrigation. Two reduced irrigation scenarios were also simulated, the first reduced the irrigation season to June and July, the second eliminated every other irrigation application. The simulation that recreated the actual management showed that non-irrigated tracts did not substantially reduce the consumptive use because water from the surrounding irrigated tracts was able to flow in via the shallow aquifer and provide sub-irrigation. For the full irrigation scenario the average annual consumptive use was 126,000 ac-ft/yr. For the non-irrigated scenario it was 96,000 ac-ft/yr, a reduction of 24%. For the two reduced irrigation scenarios the consumptive use was decreased by 14% and 12%. When compared to the irrigated scenario the total increase of flow to Upper Klamath Lake during the growing season was 60,000 ac-ft/yr for the non-irrigated scenario; and 36,000 ac-ft/yr and 31,000 ac-ft/yr for the two reduced irrigation scenarios respectively. Irrigation in the basin was found to transfer stream flow from the summer time to the winter time due to saturated winter conditions from late season irrigations resulting in increased runoff. There is potential for water conservation strategies in the Wood River Basin to substantially increase water flow into Upper Klamath Lake, but these strategies would have to be implemented extensively throughout the basin to reduce sub-irrigation. Close

• 5. [Article] Irrigation decision survey data for the Willamette Water 2100 project

  [suggested citation: "Jaeger, William K. (2016): Irrigation decision survey data for the Willamette Water 2100 project. OSU Libraries. Dataset. http://dx.doi.org/10.7267/N9H12ZXK"]

  Citation × Citation Citation Abstract Copy Title: Irrigation decision survey data for the Willamette Water 2100 project Author: Jaeger, William K. [suggested citation: "Jaeger, William K. (2016): Irrigation decision survey data for the Willamette Water 2100 project. OSU Libraries. Dataset. http://dx.doi.org/10.7267/N9H12ZXK"] Title: Irrigation decision survey data for the Willamette Water 2100 project Author: Jaeger, William K. [suggested citation: "Jaeger, William K. (2016): Irrigation decision survey data for the Willamette Water 2100 project. OSU Libraries. Dataset. http://dx.doi.org/10.7267/N9H12ZXK"] Close

• 6. [Article] Spring irrigation management of perennial ryegrass (Lolium perenne L.) seed production

  Introduction of later maturing cultivars of perennial ryegrass (Lolium perenne L.) places more seed production fields in a period of drought common to Oregon during vital stages of reproductive development. ...

  Citation × Citation Citation Abstract Copy Title: Spring irrigation management of perennial ryegrass (Lolium perenne L.) seed production Author: King, Craig Millhouser Introduction of later maturing cultivars of perennial ryegrass (Lolium perenne L.) places more seed production fields in a period of drought common to Oregon during vital stages of reproductive development. During these stages, the final yield of the crop is largely determined by the number of seeds set, and the development of individual seed weight. There is belief that water deficit during these periods may drastically reduce yield, which could be eliminated with properly timed spring irrigation. Therefore, this study was undertaken to (i) determine crop water use and water use efficiency of both irrigated and non-irrigated perennial ryegrass cultivars, (ii) observe any water use differences as a result of cultivar differences in perennial ryegrass, (iii) compare seed yield and seed yield components of different cultivars within irrigated and non-irrigated treatments, and (iv) determine appropriate timing and amount of irrigation to apply if it is revealed that irrigation enhances yield. A linear irrigation system was used to apply irrigation to six cultivars of perennial ryegrass in the crop years 2003 and 2004. In 2003 from 1 March to 25 July, 285 mm of water was consumed by non-irrigated plants, 365 mm when soil profile was filled once prior to peak anthesis, and 388 mm when soil moisture was maintained within 50 mm of field capacity to peak anthesis. In 2004 from 1 March to 8 July, nonirrigated plants consumed 279 mm of water, 353 mm from treatment to fill soil profile once, and 482 mm from treatment that maintained soil moisture up to peak anthesis. No statistical difference was observed in water use efficiency between treatments in 2003. In 2004 an interaction was observed between cultivars and irrigation, thus cultivars responded differently to irrigation. Contrasts revealed that cultivars responded differently with respect to water use efficiency. In 2003, irrigation to maintain soil moisture resulted in a 27% increase in yield, 18% due to an increase in seed number, and 8% due to an increase in seed weight. Irrigation to fill profile once resulted in a 21% increase in yield, 14% due to an increase in seed number, and 6% due to an increase in seed weight. In 2004 a cultivar by irrigation interaction was observed for total yield, seed weight, and seed number. Seed yield was increased by irrigation in all cultivars. In 2003, irrigation to maintain soil moisture began 3 June and corresponded with the beginning of anthesis, and proceeded to peak anthesis, 11 June. No rainfall was received during this period, or the period of seed fill which followed. In 2004 irrigation to maintain soil moisture began 29 April, and continued to peak anthesis, 4 June. Irrigation to fill profile once occurred between 3 June and 7 June in 2003, and between 31 May and 4 June in 2004. In 2004 significant rainfall occurred after peak anthesis during the period of seed fill. Data from both years suggest that irrigation to alleviate water deficit from the onset of anthesis through peak anthesis provides the plant with sufficient water to increase individual seed weight and seed set, thus improving overall yield. Title: Spring irrigation management of perennial ryegrass (Lolium perenne L.) seed production Author: King, Craig Millhouser Introduction of later maturing cultivars of perennial ryegrass (Lolium perenne L.) places more seed production fields in a period of drought common to Oregon during vital stages of reproductive development. During these stages, the final yield of the crop is largely determined by the number of seeds set, and the development of individual seed weight. There is belief that water deficit during these periods may drastically reduce yield, which could be eliminated with properly timed spring irrigation. Therefore, this study was undertaken to (i) determine crop water use and water use efficiency of both irrigated and non-irrigated perennial ryegrass cultivars, (ii) observe any water use differences as a result of cultivar differences in perennial ryegrass, (iii) compare seed yield and seed yield components of different cultivars within irrigated and non-irrigated treatments, and (iv) determine appropriate timing and amount of irrigation to apply if it is revealed that irrigation enhances yield. A linear irrigation system was used to apply irrigation to six cultivars of perennial ryegrass in the crop years 2003 and 2004. In 2003 from 1 March to 25 July, 285 mm of water was consumed by non-irrigated plants, 365 mm when soil profile was filled once prior to peak anthesis, and 388 mm when soil moisture was maintained within 50 mm of field capacity to peak anthesis. In 2004 from 1 March to 8 July, nonirrigated plants consumed 279 mm of water, 353 mm from treatment to fill soil profile once, and 482 mm from treatment that maintained soil moisture up to peak anthesis. No statistical difference was observed in water use efficiency between treatments in 2003. In 2004 an interaction was observed between cultivars and irrigation, thus cultivars responded differently to irrigation. Contrasts revealed that cultivars responded differently with respect to water use efficiency. In 2003, irrigation to maintain soil moisture resulted in a 27% increase in yield, 18% due to an increase in seed number, and 8% due to an increase in seed weight. Irrigation to fill profile once resulted in a 21% increase in yield, 14% due to an increase in seed number, and 6% due to an increase in seed weight. In 2004 a cultivar by irrigation interaction was observed for total yield, seed weight, and seed number. Seed yield was increased by irrigation in all cultivars. In 2003, irrigation to maintain soil moisture began 3 June and corresponded with the beginning of anthesis, and proceeded to peak anthesis, 11 June. No rainfall was received during this period, or the period of seed fill which followed. In 2004 irrigation to maintain soil moisture began 29 April, and continued to peak anthesis, 4 June. Irrigation to fill profile once occurred between 3 June and 7 June in 2003, and between 31 May and 4 June in 2004. In 2004 significant rainfall occurred after peak anthesis during the period of seed fill. Data from both years suggest that irrigation to alleviate water deficit from the onset of anthesis through peak anthesis provides the plant with sufficient water to increase individual seed weight and seed set, thus improving overall yield. Close

• 7. [Article] Drip vs. furrow irrigation in the delivery of Escherichia coli to onions

  This is the publisher’s final pdf. The published article is copyrighted by the American Society of Agricultural and Biological Engineers and can be found at: https://elibrary.asabe.org/toc_landing.asp?...

  Citation × Citation Citation Abstract Copy Title: Drip vs. furrow irrigation in the delivery of Escherichia coli to onions Author: Shock, C. C., Kreeft, H., Roncarati, R. A., Reitz, S. R., Klauzer, J. C., Shock, B. M. This is the publisher’s final pdf. The published article is copyrighted by the American Society of Agricultural and Biological Engineers and can be found at: https://elibrary.asabe.org/toc_landing.asp?conf=aeaj Title: Drip vs. furrow irrigation in the delivery of Escherichia coli to onions Author: Shock, C. C., Kreeft, H., Roncarati, R. A., Reitz, S. R., Klauzer, J. C., Shock, B. M. This is the publisher’s final pdf. The published article is copyrighted by the American Society of Agricultural and Biological Engineers and can be found at: https://elibrary.asabe.org/toc_landing.asp?conf=aeaj Close

• 8. [Article] Effects of irrigation frequency on yields of winter wheat

  Deliberately underirrigating a crop may yield economic benefits. The optimal use of water by an irrigator should be achieved under a deficit irrigation regime. It is important to know how water deficits ...

  Citation × Citation Citation Abstract Copy Title: Effects of irrigation frequency on yields of winter wheat Author: Nakamura, Brian Clifford Deliberately underirrigating a crop may yield economic benefits. The optimal use of water by an irrigator should be achieved under a deficit irrigation regime. It is important to know how water deficits affect yields and the interaction of the deficits with the scheduling of irrigations. A field experiment was conducted during the 1981 irrigation season to investigate the effects of high and low frequency deficit irrigation on yields of winter wheat. Yield and water use data were used to construct three production functions. The relationship between the level of water use and the resulting yield were determined for three irrigation frequency regimes. Field plots under daily (high frequency), weekly (normal frequency), and stress (reduced frequency) regimes were included in the field experiment as well as two dryland production plots. The relationships derived from this project were characterized by a large degree of scatter in the results. Highly favorable weather conditions offset the effects of irrigation deficits on plant yields throughout the irrigation season. At this time, a second year of data is in the process of compilation. The results of a regression analysis showed no statistically significant difference in the water use-yield relationships of the three irrigation frequency regimes. The effect of frequency did not lead to any readily apparent differences in the three production functions. The efficiency of water use of the different irrigation frequencies increases with decreasing amount of applied water for the 1981 crop year. The most efficient treatment, i.e., least water use per unit of yield, was the pre-plant irrigated, dryfarmed plots. The density of the wheat, a measure of crop quality also increased with decreased water use in this experiment. The optimal irrigation treatment (measured by production and quality) was the two-week frequency set. Title: Effects of irrigation frequency on yields of winter wheat Author: Nakamura, Brian Clifford Deliberately underirrigating a crop may yield economic benefits. The optimal use of water by an irrigator should be achieved under a deficit irrigation regime. It is important to know how water deficits affect yields and the interaction of the deficits with the scheduling of irrigations. A field experiment was conducted during the 1981 irrigation season to investigate the effects of high and low frequency deficit irrigation on yields of winter wheat. Yield and water use data were used to construct three production functions. The relationship between the level of water use and the resulting yield were determined for three irrigation frequency regimes. Field plots under daily (high frequency), weekly (normal frequency), and stress (reduced frequency) regimes were included in the field experiment as well as two dryland production plots. The relationships derived from this project were characterized by a large degree of scatter in the results. Highly favorable weather conditions offset the effects of irrigation deficits on plant yields throughout the irrigation season. At this time, a second year of data is in the process of compilation. The results of a regression analysis showed no statistically significant difference in the water use-yield relationships of the three irrigation frequency regimes. The effect of frequency did not lead to any readily apparent differences in the three production functions. The efficiency of water use of the different irrigation frequencies increases with decreasing amount of applied water for the 1981 crop year. The most efficient treatment, i.e., least water use per unit of yield, was the pre-plant irrigated, dryfarmed plots. The density of the wheat, a measure of crop quality also increased with decreased water use in this experiment. The optimal irrigation treatment (measured by production and quality) was the two-week frequency set. Close

• 9. [Article] Towards autonomous irrigation : comparison of two moisture sensing technologies, irrigation distribution analysis, and wireless network performance at an ornamental container nursery

  As ornamental container nurseries face diminishing water allocations, many are looking to automated irrigation solutions to increase their water application efficiency. This thesis presents the findings ...

  Citation × Citation Citation Abstract Copy Title: Towards autonomous irrigation : comparison of two moisture sensing technologies, irrigation distribution analysis, and wireless network performance at an ornamental container nursery Author: Bailey, Daniel R. (Daniel Roger) As ornamental container nurseries face diminishing water allocations, many are looking to automated irrigation solutions to increase their water application efficiency. This thesis presents the findings of a study conducted at a commercial container nursery to determine 1) whether a capacitance or load cell sensor was better suited for monitoring volumetric water content in the substrate; 2) if the actual irrigation distribution conformed to the expected pattern, how uniform were the weights of plants, and how these combined with plant canopy affected the leaching fraction; and 3) the reliability of the wireless network used to transmit the data to a central database. It was found that 1) the load cells outperformed the capacitance-based sensors because the load cells took an integrated measure; 2) the actual irrigation pattern followed the expected pattern, the variation of irrigation sections were low (C.V. = 0.06) and similar (C.V. ranging from 0.029 to 0.12), and unpruned plant canopies produced greater leaching fraction than pruned canopies (P < 0.18); and 3) wireless network transmission reliability was low (75.2%), suggesting that the system was not suitable for real-time irrigation control, but was sufficient for calculating irrigation length and monitoring net effective irrigation application and evapotranspirative consumption. Title: Towards autonomous irrigation : comparison of two moisture sensing technologies, irrigation distribution analysis, and wireless network performance at an ornamental container nursery Author: Bailey, Daniel R. (Daniel Roger) As ornamental container nurseries face diminishing water allocations, many are looking to automated irrigation solutions to increase their water application efficiency. This thesis presents the findings of a study conducted at a commercial container nursery to determine 1) whether a capacitance or load cell sensor was better suited for monitoring volumetric water content in the substrate; 2) if the actual irrigation distribution conformed to the expected pattern, how uniform were the weights of plants, and how these combined with plant canopy affected the leaching fraction; and 3) the reliability of the wireless network used to transmit the data to a central database. It was found that 1) the load cells outperformed the capacitance-based sensors because the load cells took an integrated measure; 2) the actual irrigation pattern followed the expected pattern, the variation of irrigation sections were low (C.V. = 0.06) and similar (C.V. ranging from 0.029 to 0.12), and unpruned plant canopies produced greater leaching fraction than pruned canopies (P < 0.18); and 3) wireless network transmission reliability was low (75.2%), suggesting that the system was not suitable for real-time irrigation control, but was sufficient for calculating irrigation length and monitoring net effective irrigation application and evapotranspirative consumption. Close

• 10. [Article] The effects of farm and operator characteristics, knowledge, and attitudes on farm-level improvements in irrigation efficiency in the central Willamette Valley

  A study was conducted using data collected from a sample of mint and vegetable farmers in the Willamette Valley of Oregon. The study identifies the influence of demographic differences, economic factors ...

  Citation × Citation Citation Abstract Copy Title: The effects of farm and operator characteristics, knowledge, and attitudes on farm-level improvements in irrigation efficiency in the central Willamette Valley Author: Stoff, Mary Cora A study was conducted using data collected from a sample of mint and vegetable farmers in the Willamette Valley of Oregon. The study identifies the influence of demographic differences, economic factors and irrigator attitudes on irrigation efficiency. Only two of the 19 characteristics theorized to influence irrigation efficiency proved to be statistically significant in both of two models. These significant variables, crop type (CROP), soil type (SOIL) suggest that a farmer's irrigation efficiency is unaffected by personal characteristics or attitudes. According to these results, the irrigator apparently applied the water that she deemed necessary, a decision based solely on the needs of the crop and the water-holding capacity of the soil. Title: The effects of farm and operator characteristics, knowledge, and attitudes on farm-level improvements in irrigation efficiency in the central Willamette Valley Author: Stoff, Mary Cora A study was conducted using data collected from a sample of mint and vegetable farmers in the Willamette Valley of Oregon. The study identifies the influence of demographic differences, economic factors and irrigator attitudes on irrigation efficiency. Only two of the 19 characteristics theorized to influence irrigation efficiency proved to be statistically significant in both of two models. These significant variables, crop type (CROP), soil type (SOIL) suggest that a farmer's irrigation efficiency is unaffected by personal characteristics or attitudes. According to these results, the irrigator apparently applied the water that she deemed necessary, a decision based solely on the needs of the crop and the water-holding capacity of the soil. Close

• 11. [Article] Irrigation choices for major West Coast crops : water scarcity and climatic determinants

  Recent climate change forecasts have aroused growing interest in the influence of water scarcity and climate on agricultural production and irrigation practice. However, it is common in the economic literature ...

  Citation × Citation Citation Abstract Copy Title: Irrigation choices for major West Coast crops : water scarcity and climatic determinants Author: Olen, Beau Recent climate change forecasts have aroused growing interest in the influence of water scarcity and climate on agricultural production and irrigation practice. However, it is common in the economic literature to aggregate disparate crops when modeling irrigation choices. That approach confounds the crop-specific effects of climate and water scarcity that govern such choices. Given the sensitivity of agricultural production to water scarcity and climate, understanding their influence on irrigation choices is a key contribution to policy evaluation. This paper addresses the impact of water scarcity and climate on irrigation choices through estimated models of cropland proportion irrigated (PI), and crop-specific irrigation technology choice (TC) and water application rates (AR). This approach is applied to agricultural production data for major crops (orchard/vineyard, vegetable, wheat, alfalfa, hay, and pasture) on the West Coast (California, Oregon, and Washington). Crop-specific modeling provides information about the distributional impacts of agricultural policy and climate change. This advantage is particularly important for the diverse agricultural landscape of the West Coast, where the distributional impacts of policy can be complex. The most important policy implications that are found involve asset heterogeneity and the distributional impacts of agricultural policy. Several findings provide valuable information about how irrigators would respond and adapt to climate change. The current findings also lead to commonly advocated revisions to federal water subsidy policies. Some key differences between the irrigation choices of higher- and lower-value crops are also identified. Identifying these differences sheds further light on the distributional consequences of agricultural policy. Many findings from this research are crop-specific and will have a high degree of policy relevance to irrigation districts or other agricultural jurisdictions that cultivate some of the West Coast's major crops. Furthermore, the data used in this research has a large degree of variation in water scarcity and climate, making the findings applicable to other Mediterranean climates in the world. It is found that specific crops have a proclivity for certain irrigation technologies that can mitigate particular climatic stressors (i.e., frost damage and heat stress). For example, the results indicate that water pricing policies will tend not to encourage water conservation by technology adoption for many orchards, vineyards, and vegetable farms, thereby imposing pure costs to these producers. In essence, climate heterogeneity limits options available to farmers and reduces the set of production technologies that a farm can use. This finding exemplifies that with climate heterogeneity, the distribution of water policy impacts depends on prior land allocation decisions such as crop choices. Heterogeneity in land quality is also found to have important influences on TC. The effects of temperature on irrigation choices are found to be more profound than the effects of precipitation. Because of the large study region used, the effects of temperature and precipitation on irrigation choices are often found to be quadratic-like. These quadratic-like relationships reveal thresholds where irrigators begin to respond very differently to climate. However, this was not the case for all crops. Thus, it is demonstrated that the effects of climate on irrigation choices are crop-dependent. The results indicate that for several crops, the discontinuance of irrigation water (i.e., water supply or price uncertainty) creates an option value that delays and discourages adoption of water-saving technologies. The discontinuance of irrigation water is also shown to reduce water demand at the farm-level extensive proportion (i.e., PI) and crop-level intensive margin (i.e., AR). Water price is found to impact all three irrigation choices as well. Well depth is found to facilitate adoption of water-saving technologies for several crops. This paper demonstrates that irrigation choices are highly dependent on water scarcity and climate. Institutional arrangements, geographic qualities of the farm, and demographic characteristics of the farmer also exhibit important influences on irrigation choices. By using crop-specific equations, quadratic climate variables, and a study region with large variation in climate conditions, this research resolves many inconsistent findings regarding the determinants of irrigation choices. Furthermore, this study establishes a research agenda for crop-specific analysis of irrigation choices. Some of the estimated results warrant verification with further studies. Future crop-specific irrigation choice studies would benefit from panel micro data with improved land quality variables, and seasonal or monthly climate variables that are better able to identify the effects of climate stress (e.g., heat stress and frost damage) on irrigation choices. Title: Irrigation choices for major West Coast crops : water scarcity and climatic determinants Author: Olen, Beau Recent climate change forecasts have aroused growing interest in the influence of water scarcity and climate on agricultural production and irrigation practice. However, it is common in the economic literature to aggregate disparate crops when modeling irrigation choices. That approach confounds the crop-specific effects of climate and water scarcity that govern such choices. Given the sensitivity of agricultural production to water scarcity and climate, understanding their influence on irrigation choices is a key contribution to policy evaluation. This paper addresses the impact of water scarcity and climate on irrigation choices through estimated models of cropland proportion irrigated (PI), and crop-specific irrigation technology choice (TC) and water application rates (AR). This approach is applied to agricultural production data for major crops (orchard/vineyard, vegetable, wheat, alfalfa, hay, and pasture) on the West Coast (California, Oregon, and Washington). Crop-specific modeling provides information about the distributional impacts of agricultural policy and climate change. This advantage is particularly important for the diverse agricultural landscape of the West Coast, where the distributional impacts of policy can be complex. The most important policy implications that are found involve asset heterogeneity and the distributional impacts of agricultural policy. Several findings provide valuable information about how irrigators would respond and adapt to climate change. The current findings also lead to commonly advocated revisions to federal water subsidy policies. Some key differences between the irrigation choices of higher- and lower-value crops are also identified. Identifying these differences sheds further light on the distributional consequences of agricultural policy. Many findings from this research are crop-specific and will have a high degree of policy relevance to irrigation districts or other agricultural jurisdictions that cultivate some of the West Coast's major crops. Furthermore, the data used in this research has a large degree of variation in water scarcity and climate, making the findings applicable to other Mediterranean climates in the world. It is found that specific crops have a proclivity for certain irrigation technologies that can mitigate particular climatic stressors (i.e., frost damage and heat stress). For example, the results indicate that water pricing policies will tend not to encourage water conservation by technology adoption for many orchards, vineyards, and vegetable farms, thereby imposing pure costs to these producers. In essence, climate heterogeneity limits options available to farmers and reduces the set of production technologies that a farm can use. This finding exemplifies that with climate heterogeneity, the distribution of water policy impacts depends on prior land allocation decisions such as crop choices. Heterogeneity in land quality is also found to have important influences on TC. The effects of temperature on irrigation choices are found to be more profound than the effects of precipitation. Because of the large study region used, the effects of temperature and precipitation on irrigation choices are often found to be quadratic-like. These quadratic-like relationships reveal thresholds where irrigators begin to respond very differently to climate. However, this was not the case for all crops. Thus, it is demonstrated that the effects of climate on irrigation choices are crop-dependent. The results indicate that for several crops, the discontinuance of irrigation water (i.e., water supply or price uncertainty) creates an option value that delays and discourages adoption of water-saving technologies. The discontinuance of irrigation water is also shown to reduce water demand at the farm-level extensive proportion (i.e., PI) and crop-level intensive margin (i.e., AR). Water price is found to impact all three irrigation choices as well. Well depth is found to facilitate adoption of water-saving technologies for several crops. This paper demonstrates that irrigation choices are highly dependent on water scarcity and climate. Institutional arrangements, geographic qualities of the farm, and demographic characteristics of the farmer also exhibit important influences on irrigation choices. By using crop-specific equations, quadratic climate variables, and a study region with large variation in climate conditions, this research resolves many inconsistent findings regarding the determinants of irrigation choices. Furthermore, this study establishes a research agenda for crop-specific analysis of irrigation choices. Some of the estimated results warrant verification with further studies. Future crop-specific irrigation choice studies would benefit from panel micro data with improved land quality variables, and seasonal or monthly climate variables that are better able to identify the effects of climate stress (e.g., heat stress and frost damage) on irrigation choices. Close

• 12. [Article] Irrigation to Enhance Native Seed Production for Great Basin Restoration

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the Natural ...

  Citation × Citation Citation Abstract Copy Title: Irrigation to Enhance Native Seed Production for Great Basin Restoration Author: Shaw, Nancy L., Shock, Myrtle P., Saunders, Lamont D., Shock, Clinton C., Feibert, Erik B. G. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the Natural Areas Association and can be found at: https://naturalareas.org/journal. Title: Irrigation to Enhance Native Seed Production for Great Basin Restoration Author: Shaw, Nancy L., Shock, Myrtle P., Saunders, Lamont D., Shock, Clinton C., Feibert, Erik B. G. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the Natural Areas Association and can be found at: https://naturalareas.org/journal. Close

• 13. [Article] Addressing Data Resolution in Precision Agriculture

  Irrigated agriculture constitutes the greatest consumptive water use globally, so that irrigation efficiency measures are an important part of global efforts to best utilize this limited resource. However, ...

  Citation × Citation Citation Abstract Copy Title: Addressing Data Resolution in Precision Agriculture Author: Kelley, Jason Irrigated agriculture constitutes the greatest consumptive water use globally, so that irrigation efficiency measures are an important part of global efforts to best utilize this limited resource. However, greater irrigation efficiency must be achieved while simultaneously maintaining or increasing crop yields and farming profitability. Incremental water use decisions are made at the local level by farmers under many real world constraints; consequently they face significant risks in operating large and complex irrigation systems. These decisions should be supported by reliable information upon which to base operational plans and irrigation scheduling. Implementing precision irrigation effectively depends upon highly resolved estimates of crop water demand so that application rates match demand precisely both in location and timing. A fundamental challenge in mapping the irrigation requirement is addressing the heterogeneity of soil, biophysical, and atmospheric processes which mediate water demand. However, existing methods to determine the irrigation requirement assume that field conditions are homogeneous. Precision irrigation systems may enable more specific water distribution than traditional irrigation equipment, but allocating the correct amount of water requires crop water estimates that accurately reflect the variability of the irrigation requirement and consider the scale and timing at which irrigation can be delivered. This dissertation synthesizes the results from field studies which analyzed spatial patterns of irrigation performance and crop water demand under real field conditions. The first experiment quantified the performance of a precision irrigation system and determined the data resolution required for effective utilization of the system’s capability (Chapter 2). Field trials were conducted with a variable rate center pivot sprinkler (VRI) under normal farming conditions to determine this spatial resolution. The result was the definition of a performance coefficient and characteristic length scale associated with the irrigation system. The characteristic length scale describes the highest resolution prescription possible with VRI. Following on these findings, a second study compares an electromagnetic (EM) soil mapping method using extensive laboratory soil characterization as a basis for comparison (Chapter 3). The motivation of the study was to validate the EM method’s capability to detect small scale variations in soil water holding capacity, and to determine under which conditions the EM method can obtain reliable and robust soil maps. The findings reinforce earlier work on the importance of instrument calibration, and also show that specific soil characteristics may preclude using EM methods to map soil in some regions. Following the soil mapping study, further studies investigated methods to measure crop evapotranspiration (ET). A literature review was conducted to establish a catalog of contemporary methods to monitor ET, focusing on those commonly used in agriculture (Chapter 4). From this review, the surface renewal method (SR) emerged as potentially able to map ET feasibly and cost-effectively. Four field experiments were conducted over two years under a range of field conditions to establish a robust protocol for the determination of surface fluxes with SR (Chapter 5). Three of these experiments specifically investigated the potential for SR to be implemented from a moving sensor platform, such as an unmanned aerial vehicle. Experiments showed SR could estimate sensible heat flux as accurately as eddy covariance during moving trials. However, analysis of the minimum flux averaging period demonstrated that SR cannot resolve fluxes at the requisite spatial scales for precision irrigation. Nonetheless, SR remains promising for other practical applications in measuring surface fluxes. Future research questions and potential applications are explored in Chapters 5 and 6. The methods described here are directly relevant to water managers at the levels of farms and irrigation districts. Efficient irrigation planning depends on timely, reliable, and site-specific information in order to anticipate crop water demand, irrigate adequately to prevent drought stress, and maximize yield from the available resource. Growers and irrigation specialists currently have many resources at their disposal, including regional and satellite based ET estimates, state and local soil mapping, and scientific irrigation planning software. However, these methods do not provide site-specific and real time measurements of actual crop water demand, and farmers do not have any reliable means by which to validate the accuracy and precision of these estimates. For this information to be directly useful in irrigation planning, it should be validated by on site measurements. Reliable, local, and real time information is required to realize the full potential of precision agriculture. Title: Addressing Data Resolution in Precision Agriculture Author: Kelley, Jason Irrigated agriculture constitutes the greatest consumptive water use globally, so that irrigation efficiency measures are an important part of global efforts to best utilize this limited resource. However, greater irrigation efficiency must be achieved while simultaneously maintaining or increasing crop yields and farming profitability. Incremental water use decisions are made at the local level by farmers under many real world constraints; consequently they face significant risks in operating large and complex irrigation systems. These decisions should be supported by reliable information upon which to base operational plans and irrigation scheduling. Implementing precision irrigation effectively depends upon highly resolved estimates of crop water demand so that application rates match demand precisely both in location and timing. A fundamental challenge in mapping the irrigation requirement is addressing the heterogeneity of soil, biophysical, and atmospheric processes which mediate water demand. However, existing methods to determine the irrigation requirement assume that field conditions are homogeneous. Precision irrigation systems may enable more specific water distribution than traditional irrigation equipment, but allocating the correct amount of water requires crop water estimates that accurately reflect the variability of the irrigation requirement and consider the scale and timing at which irrigation can be delivered. This dissertation synthesizes the results from field studies which analyzed spatial patterns of irrigation performance and crop water demand under real field conditions. The first experiment quantified the performance of a precision irrigation system and determined the data resolution required for effective utilization of the system’s capability (Chapter 2). Field trials were conducted with a variable rate center pivot sprinkler (VRI) under normal farming conditions to determine this spatial resolution. The result was the definition of a performance coefficient and characteristic length scale associated with the irrigation system. The characteristic length scale describes the highest resolution prescription possible with VRI. Following on these findings, a second study compares an electromagnetic (EM) soil mapping method using extensive laboratory soil characterization as a basis for comparison (Chapter 3). The motivation of the study was to validate the EM method’s capability to detect small scale variations in soil water holding capacity, and to determine under which conditions the EM method can obtain reliable and robust soil maps. The findings reinforce earlier work on the importance of instrument calibration, and also show that specific soil characteristics may preclude using EM methods to map soil in some regions. Following the soil mapping study, further studies investigated methods to measure crop evapotranspiration (ET). A literature review was conducted to establish a catalog of contemporary methods to monitor ET, focusing on those commonly used in agriculture (Chapter 4). From this review, the surface renewal method (SR) emerged as potentially able to map ET feasibly and cost-effectively. Four field experiments were conducted over two years under a range of field conditions to establish a robust protocol for the determination of surface fluxes with SR (Chapter 5). Three of these experiments specifically investigated the potential for SR to be implemented from a moving sensor platform, such as an unmanned aerial vehicle. Experiments showed SR could estimate sensible heat flux as accurately as eddy covariance during moving trials. However, analysis of the minimum flux averaging period demonstrated that SR cannot resolve fluxes at the requisite spatial scales for precision irrigation. Nonetheless, SR remains promising for other practical applications in measuring surface fluxes. Future research questions and potential applications are explored in Chapters 5 and 6. The methods described here are directly relevant to water managers at the levels of farms and irrigation districts. Efficient irrigation planning depends on timely, reliable, and site-specific information in order to anticipate crop water demand, irrigate adequately to prevent drought stress, and maximize yield from the available resource. Growers and irrigation specialists currently have many resources at their disposal, including regional and satellite based ET estimates, state and local soil mapping, and scientific irrigation planning software. However, these methods do not provide site-specific and real time measurements of actual crop water demand, and farmers do not have any reliable means by which to validate the accuracy and precision of these estimates. For this information to be directly useful in irrigation planning, it should be validated by on site measurements. Reliable, local, and real time information is required to realize the full potential of precision agriculture. Close

• 14. [Article] Identification of irrigation practices using photographic and optical-mechanical scanning remote sensing techniques

  Irrigation is essential for profitable agriculture in the western United States. It is the largest consumer of water and power in Oregon. Conflicting uses of water and power and their scarcity demands judicious ...

  Citation × Citation Citation Abstract Copy Title: Identification of irrigation practices using photographic and optical-mechanical scanning remote sensing techniques Author: Naim, Shamim Irrigation is essential for profitable agriculture in the western United States. It is the largest consumer of water and power in Oregon. Conflicting uses of water and power and their scarcity demands judicious planning for allocation of these resources. Creditable baseline data are not only needed for irrigated crop acreages, but also for irrigation methods as an indicator of amount of water and power used. A data-gathering system is needed which is quick, reliable and comparatively inexpensive. The primary objective of this research was to develop a methodology to use remotely sensed data for irrigation method identification. The main tasks were to: (1) analyze multidate images for different emulsions and scales to identify irrigation methods: (2) develop mission parameters; (3) develop an image interpretation key; (4) investigate the feasibility of using a quantitative approach to irrigation method identification. The North Unit Deschutes Irrigation District of central Oregon was selected to develop and test the methodology. Field layout of different irrigation methods, their association with crops, soils, and slopes were noted for the area imaged by three CIR aerial flights during the 1979 growing season. A detailed crop calendar showing different phenological stages that affect the spectral properties of crops was developed. Images used for analysis included: Landsat MSS color transparencies at 1:1,000,000 for June 4, June 22, July 18, 1979; Landsat MSS color prints at 1:250,000 for May 17, and June 22, 1979; Landsat RBV images at 1:125,000 for June 8, 1978 and July 28, 1979; U-2 CIR photographs at 1:30,000 for June 28, 1973 and at 1:130,000 for August 2, 1978; CIR aerial photographs for May 12, July 9, and August 5, 1979 at 1:30,000 and 1:23,000. Two methods of analysis were used. Manual interpretation of the images employed light tables, magnifiers and stereomicroscope. Each test field along the flight line was carefully studied for detection of irrigation patterns using associated tones, colors, textures, and their temporal variations, in addition to crop calendar data, soil, and slope maps, ground information gathered, and black and white images at 1:8,000. Digital analysis of the data for discrimination of irrigated and non-irrigated crop types was discouraging as the data were for the late growing season (July 28, 1979), when most crops were either harvested or in the senescing stage and their spectral signatures overlapped. Conclusions drawn from this study are that: image-oriented analysis rather than quantitative analysis is best suited for irrigation method discrimination; CIR images provide better discrimination than black and white images; while irrigated and non-irrigated crops can be discriminated using multidate 1:1,000,000 images, for satisfactory discrimination of all irrigation methods, 1:30,000 or larger imagery is needed; and the best time for differentiating irrigation methods is the early growing season. As a result of this research, optimum mission parameters for flying photographic missions were developed and an image interpretation key useful for irrigation methods discrimination was developed. Title: Identification of irrigation practices using photographic and optical-mechanical scanning remote sensing techniques Author: Naim, Shamim Irrigation is essential for profitable agriculture in the western United States. It is the largest consumer of water and power in Oregon. Conflicting uses of water and power and their scarcity demands judicious planning for allocation of these resources. Creditable baseline data are not only needed for irrigated crop acreages, but also for irrigation methods as an indicator of amount of water and power used. A data-gathering system is needed which is quick, reliable and comparatively inexpensive. The primary objective of this research was to develop a methodology to use remotely sensed data for irrigation method identification. The main tasks were to: (1) analyze multidate images for different emulsions and scales to identify irrigation methods: (2) develop mission parameters; (3) develop an image interpretation key; (4) investigate the feasibility of using a quantitative approach to irrigation method identification. The North Unit Deschutes Irrigation District of central Oregon was selected to develop and test the methodology. Field layout of different irrigation methods, their association with crops, soils, and slopes were noted for the area imaged by three CIR aerial flights during the 1979 growing season. A detailed crop calendar showing different phenological stages that affect the spectral properties of crops was developed. Images used for analysis included: Landsat MSS color transparencies at 1:1,000,000 for June 4, June 22, July 18, 1979; Landsat MSS color prints at 1:250,000 for May 17, and June 22, 1979; Landsat RBV images at 1:125,000 for June 8, 1978 and July 28, 1979; U-2 CIR photographs at 1:30,000 for June 28, 1973 and at 1:130,000 for August 2, 1978; CIR aerial photographs for May 12, July 9, and August 5, 1979 at 1:30,000 and 1:23,000. Two methods of analysis were used. Manual interpretation of the images employed light tables, magnifiers and stereomicroscope. Each test field along the flight line was carefully studied for detection of irrigation patterns using associated tones, colors, textures, and their temporal variations, in addition to crop calendar data, soil, and slope maps, ground information gathered, and black and white images at 1:8,000. Digital analysis of the data for discrimination of irrigated and non-irrigated crop types was discouraging as the data were for the late growing season (July 28, 1979), when most crops were either harvested or in the senescing stage and their spectral signatures overlapped. Conclusions drawn from this study are that: image-oriented analysis rather than quantitative analysis is best suited for irrigation method discrimination; CIR images provide better discrimination than black and white images; while irrigated and non-irrigated crops can be discriminated using multidate 1:1,000,000 images, for satisfactory discrimination of all irrigation methods, 1:30,000 or larger imagery is needed; and the best time for differentiating irrigation methods is the early growing season. As a result of this research, optimum mission parameters for flying photographic missions were developed and an image interpretation key useful for irrigation methods discrimination was developed. Close

• 15. [Article] Orchard irrigation

  Citation × Citation Citation Abstract Copy Title: Orchard irrigation Author: Schrack, Claud, Currin, Harvey William Title: Orchard irrigation Author: Schrack, Claud, Currin, Harvey William Close

• 16. [Article] An irrigation efficiency model for optimum irrigation management

  Citation × Citation Citation Abstract Copy Title: An irrigation efficiency model for optimum irrigation management Author: Isbell, Brett, 1978- Title: An irrigation efficiency model for optimum irrigation management Author: Isbell, Brett, 1978- Close

• 17. [Article] Scale of operation on farms in a new irrigation district, Jefferson County, Oregon 1949-1953

  Citation × Citation Citation Abstract Copy Title: Scale of operation on farms in a new irrigation district, Jefferson County, Oregon 1949-1953 Author: Benedict, Russell Archie Title: Scale of operation on farms in a new irrigation district, Jefferson County, Oregon 1949-1953 Author: Benedict, Russell Archie Close

• 18. [Article] An investigation of alternative methods of valuing irrigation water

  Citation × Citation Citation Abstract Copy Title: An investigation of alternative methods of valuing irrigation water Author: Miller, Stanley F. Title: An investigation of alternative methods of valuing irrigation water Author: Miller, Stanley F. Close

• 19. [Article] An economic analysis of irrigation development in Nam Pong Irrigation Project, Khon Kaen, Thailand

  Citation × Citation Citation Abstract Copy Title: An economic analysis of irrigation development in Nam Pong Irrigation Project, Khon Kaen, Thailand Author: Sriswasdilek, Jerachone Title: An economic analysis of irrigation development in Nam Pong Irrigation Project, Khon Kaen, Thailand Author: Sriswasdilek, Jerachone Close

• 20. [Article] Economic optimization of irrigation

  Citation × Citation Citation Abstract Copy Title: Economic optimization of irrigation Author: English, Marshall J. Title: Economic optimization of irrigation Author: English, Marshall J. Close

• 21. [Article] Response of field corn to irrigation, plant population, and nitrogen on soils of the Willamette catena

  The purpose of this study was to make a preliminary investigation of the productivity of some of the soils within the Willamette catena under different systems of soil management. The study was carried ...

  Citation × Citation Citation Abstract Copy Title: Response of field corn to irrigation, plant population, and nitrogen on soils of the Willamette catena Author: Andersen, Jimmie Lee The purpose of this study was to make a preliminary investigation of the productivity of some of the soils within the Willamette catena under different systems of soil management. The study was carried out at four experimental sites near Corvallis, Oregon, during the 1962 growing season. The soil at each site was representative of a different soil series. The soil series were Willamette, Woodburn, Amity, and Dayton which are well-drained, moderately well drained, imperfectly drained, and poorly drained, respectively. Productivity was measured in terms of shelled corn yield. The eight treatments (systems of soil managements) were different combinations of irrigation, plant population, and nitrogen fertilization practices. The irrigation treatments were irrigated and non-irrigated. The Ievels of plant population were 9000, 14000, 18000, and 22000 plants per acre. The rates of nitrogen fertilization were 60 and 180 pounds of N per acre. A second objective of this study was to measure the response of field corn to each of the three soil management practices. Data pertaining to the effects of the three practices on shelling percentage and ear moisture at harvest, as well as grain yield, were collected. There were significant yield responses to irrigation when accompanied by higher levels of plant population at all sites. Generally, yield responses to higher levels of plant population and the higher rate of nitrogen fertilization were measured on the irrigated plots, but not on the non-irrigated plots. The shelling percentage on the irrigated plots was higher than that on the non-irrigated plots only at the Amity and Dayton sites. Apparently, plant population and nitrogen had no effect on shelling percentage. The amount of moisture in the ears at harvest was apparently not affected by irrigation, plant population, and nitrogen fertilization practices. In general, the productivities of the soils at the Willamette, Woodburn, and Amity sites were similar and significantly greater than at the Dayton site under all systems of soil management. Title: Response of field corn to irrigation, plant population, and nitrogen on soils of the Willamette catena Author: Andersen, Jimmie Lee The purpose of this study was to make a preliminary investigation of the productivity of some of the soils within the Willamette catena under different systems of soil management. The study was carried out at four experimental sites near Corvallis, Oregon, during the 1962 growing season. The soil at each site was representative of a different soil series. The soil series were Willamette, Woodburn, Amity, and Dayton which are well-drained, moderately well drained, imperfectly drained, and poorly drained, respectively. Productivity was measured in terms of shelled corn yield. The eight treatments (systems of soil managements) were different combinations of irrigation, plant population, and nitrogen fertilization practices. The irrigation treatments were irrigated and non-irrigated. The Ievels of plant population were 9000, 14000, 18000, and 22000 plants per acre. The rates of nitrogen fertilization were 60 and 180 pounds of N per acre. A second objective of this study was to measure the response of field corn to each of the three soil management practices. Data pertaining to the effects of the three practices on shelling percentage and ear moisture at harvest, as well as grain yield, were collected. There were significant yield responses to irrigation when accompanied by higher levels of plant population at all sites. Generally, yield responses to higher levels of plant population and the higher rate of nitrogen fertilization were measured on the irrigated plots, but not on the non-irrigated plots. The shelling percentage on the irrigated plots was higher than that on the non-irrigated plots only at the Amity and Dayton sites. Apparently, plant population and nitrogen had no effect on shelling percentage. The amount of moisture in the ears at harvest was apparently not affected by irrigation, plant population, and nitrogen fertilization practices. In general, the productivities of the soils at the Willamette, Woodburn, and Amity sites were similar and significantly greater than at the Dayton site under all systems of soil management. Close

• 22. [Article] Evaluation of erosion and sediment loss in furrow irrigation with alternative irrigation practices

  Citation × Citation Citation Abstract Copy Title: Evaluation of erosion and sediment loss in furrow irrigation with alternative irrigation practices Author: Tunio, Abdul Fatah Title: Evaluation of erosion and sediment loss in furrow irrigation with alternative irrigation practices Author: Tunio, Abdul Fatah Close

• 23. [Article] Deep well irrigation in Hamilton County, Nebraska : resource, development, impact and future

  Citation × Citation Citation Abstract Copy Title: Deep well irrigation in Hamilton County, Nebraska : resource, development, impact and future Author: Nelson, Charles Edward Title: Deep well irrigation in Hamilton County, Nebraska : resource, development, impact and future Author: Nelson, Charles Edward Close

• 24. [Article] Simple irrigation scheduling using the "look and feel" method

  Published August 1998. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catal...

  Citation × Citation Citation Abstract Copy Title: Simple irrigation scheduling using the "look and feel" method Author: Long, L. E. (Lynn Edwards), 1953-, Oregon State University. Extension Service, Niederholzer, Franz Published August 1998. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: Simple irrigation scheduling using the "look and feel" method Author: Long, L. E. (Lynn Edwards), 1953-, Oregon State University. Extension Service, Niederholzer, Franz Published August 1998. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close

• 25. [Article] Efficient lawn irrigation in the Intermountain West

  Published October 2010. Reviewed November 2014. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog

  Citation × Citation Citation Abstract Copy Title: Efficient lawn irrigation in the Intermountain West Author: Charlton, Brian A., Cook, Thomas W., Golembiewski, Robert Craig, 1969-, Oregon State University. Extension Service Published October 2010. Reviewed November 2014. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: Efficient lawn irrigation in the Intermountain West Author: Charlton, Brian A., Cook, Thomas W., Golembiewski, Robert Craig, 1969-, Oregon State University. Extension Service Published October 2010. Reviewed November 2014. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close

• 26. [Article] Successful potato irrigation scheduling

  Published October 2006. Revised January 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog

  Citation × Citation Citation Abstract Copy Title: Successful potato irrigation scheduling Author: Pereira, Andre, Wang, Feng-Xin, Eldredge, Eric P., Flock, Rebecca, Oregon State University. Extension Service, Shock, C. C. (Clinton C.) Published October 2006. Revised January 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: Successful potato irrigation scheduling Author: Pereira, Andre, Wang, Feng-Xin, Eldredge, Eric P., Flock, Rebecca, Oregon State University. Extension Service, Shock, C. C. (Clinton C.) Published October 2006. Revised January 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close

• 27. [Article] Opportunity costs : irrigation vs. hydropower

  In recent years we have seen increasing debate over the allocation of PNW water resources. In particular there are conflicts over using the river system for irrigation vs. electricity production. Denying ...

  Citation × Citation Citation Abstract Copy Title: Opportunity costs : irrigation vs. hydropower Author: Ross, Mark In recent years we have seen increasing debate over the allocation of PNW water resources. In particular there are conflicts over using the river system for irrigation vs. electricity production. Denying the hydroelectric system water implies higher costs to electricity consumers as producers substitute more expensive nonhydro resources. This research looked at the impact of new irrigation on PNW electricity consumers. This was done under varying assumptions of demand response and farmer payments for pumping of irrigation water. The study also examined the difference between the current policy of allowing farmers to take all the water they need, and a policy in which withdrawals are limited in periods of low streamflow. Simulations were run to determine the amount of electricity production lost because of withdrawals. These results were then used in a series of simulations to estimate the economic impacts under the various assumptions and policies. It was found that irrigation caused losses to electricity consumers. In some cases this loss was on the order of $200/acre of irrigated land. The loss was significantly mitigated under the interruptible policy. Farmer payments for irrigation energy also reduced the loss to consumers. Title: Opportunity costs : irrigation vs. hydropower Author: Ross, Mark In recent years we have seen increasing debate over the allocation of PNW water resources. In particular there are conflicts over using the river system for irrigation vs. electricity production. Denying the hydroelectric system water implies higher costs to electricity consumers as producers substitute more expensive nonhydro resources. This research looked at the impact of new irrigation on PNW electricity consumers. This was done under varying assumptions of demand response and farmer payments for pumping of irrigation water. The study also examined the difference between the current policy of allowing farmers to take all the water they need, and a policy in which withdrawals are limited in periods of low streamflow. Simulations were run to determine the amount of electricity production lost because of withdrawals. These results were then used in a series of simulations to estimate the economic impacts under the various assumptions and policies. It was found that irrigation caused losses to electricity consumers. In some cases this loss was on the order of $200/acre of irrigated land. The loss was significantly mitigated under the interruptible policy. Farmer payments for irrigation energy also reduced the loss to consumers. Close

• 28. [Article] Hedonic price analysis to reveal value of water in irrigation : an application to northern Malheur County, Oregon

  Increasing water demand for growing municipalities, for water-based recreation and for fishery and wildlife habitat has intensified pressure on the existing resource. Reallocation of water from existing ...

  Citation × Citation Citation Abstract Copy Title: Hedonic price analysis to reveal value of water in irrigation : an application to northern Malheur County, Oregon Author: Faux, John Increasing water demand for growing municipalities, for water-based recreation and for fishery and wildlife habitat has intensified pressure on the existing resource. Reallocation of water from existing uses to other, higher-valued uses is receiving greater attention due to constraints on development of new water supplies. A key to reallocation is identification of the economic value associated with existing and alternative water uses. A hedonic price analysis of farm sales in eastern Oregon is performed to reveal the value of water used in irrigation. Estimation includes a joint test of heteroskedasticity and functional form. The value of water is shown to be strongly influenced by the crop-growing-capability of the soil on which it is applied. The value of an irrigated acre is not significantly influenced by the source of irrigation supply. The implicit market price of irrigation water in this area ranges from $44 per acre-foot (one-time delivery) on the best soils to $9 per acre-foot on the poorest soils irrigated. Title: Hedonic price analysis to reveal value of water in irrigation : an application to northern Malheur County, Oregon Author: Faux, John Increasing water demand for growing municipalities, for water-based recreation and for fishery and wildlife habitat has intensified pressure on the existing resource. Reallocation of water from existing uses to other, higher-valued uses is receiving greater attention due to constraints on development of new water supplies. A key to reallocation is identification of the economic value associated with existing and alternative water uses. A hedonic price analysis of farm sales in eastern Oregon is performed to reveal the value of water used in irrigation. Estimation includes a joint test of heteroskedasticity and functional form. The value of water is shown to be strongly influenced by the crop-growing-capability of the soil on which it is applied. The value of an irrigated acre is not significantly influenced by the source of irrigation supply. The implicit market price of irrigation water in this area ranges from $44 per acre-foot (one-time delivery) on the best soils to $9 per acre-foot on the poorest soils irrigated. Close

• 29. [Article] Linking GIS and a surface irrigation model to evaluate regional effects of furrow irrigation strategies

  The shallow aquifer in Northeast Malheur County, Oregon is polluted with Nitrates at concentrations exceeding federal drinking water standards. Efforts to solve the groundwater problems in this area have ...

  Citation × Citation Citation Abstract Copy Title: Linking GIS and a surface irrigation model to evaluate regional effects of furrow irrigation strategies Author: Faux, Russell N. The shallow aquifer in Northeast Malheur County, Oregon is polluted with Nitrates at concentrations exceeding federal drinking water standards. Efforts to solve the groundwater problems in this area have focused on developing farm management practices that will increase groundwater quality while maintaining agricultural production. Furrow irrigation is the dominant practice for irrigating row crops in this region. One potential way to improve water quality is to increase furrow irrigation performance on a regional scale. In this study a surface irrigation model, SRFR, was linked to a geographic information system (GIS) for the purpose of evaluating alternate furrow irrigation strategies in Malheur County, Oregon. SRFR is a physically based model that simulates water flow and distribution in irrigated furrows. The model accepts the management parameters that influence the outcome of an irrigation and in return provides measures of water application efficiency, amount of deep percolation, amount of surface run-off, and other performance indicators. The GIS, constructed using ARC/INFO software, contains the spatial data required to run SRFR on individual fields in the region. The data for the GIS were acquired using many different sources and techniques in order to meet the input resolution required by the irrigation model. The primary goal of this research was to develop a tool for evaluating irrigation practices on a regional scale, accounting for the diversity of physical circumstances and management practices that occur within a complex of several hundred farms. The particular application of this tool was for control of nitrate pollution of groundwater in the vicinity of Ontario, Oregon. The integrated system was used to estimate a base condition irrigation that is representative of current irrigation practices. The system was then used to assess irrigation performance using three alternative practices: 1) separate management of wheel and nonwheel compacted furrows; 2) use of an automated control system to vary application set times; and 3) cutback irrigation. Although this represents only a limited assessment of the alternatives that might be considered for the study area, preliminary results suggest that under certain field conditions irrigation efficiency can potentially improve more then 20% over the base condition using alternate strategies. The system demonstrated tremendous potential for identifying trends and variability in system performance in the region. Title: Linking GIS and a surface irrigation model to evaluate regional effects of furrow irrigation strategies Author: Faux, Russell N. The shallow aquifer in Northeast Malheur County, Oregon is polluted with Nitrates at concentrations exceeding federal drinking water standards. Efforts to solve the groundwater problems in this area have focused on developing farm management practices that will increase groundwater quality while maintaining agricultural production. Furrow irrigation is the dominant practice for irrigating row crops in this region. One potential way to improve water quality is to increase furrow irrigation performance on a regional scale. In this study a surface irrigation model, SRFR, was linked to a geographic information system (GIS) for the purpose of evaluating alternate furrow irrigation strategies in Malheur County, Oregon. SRFR is a physically based model that simulates water flow and distribution in irrigated furrows. The model accepts the management parameters that influence the outcome of an irrigation and in return provides measures of water application efficiency, amount of deep percolation, amount of surface run-off, and other performance indicators. The GIS, constructed using ARC/INFO software, contains the spatial data required to run SRFR on individual fields in the region. The data for the GIS were acquired using many different sources and techniques in order to meet the input resolution required by the irrigation model. The primary goal of this research was to develop a tool for evaluating irrigation practices on a regional scale, accounting for the diversity of physical circumstances and management practices that occur within a complex of several hundred farms. The particular application of this tool was for control of nitrate pollution of groundwater in the vicinity of Ontario, Oregon. The integrated system was used to estimate a base condition irrigation that is representative of current irrigation practices. The system was then used to assess irrigation performance using three alternative practices: 1) separate management of wheel and nonwheel compacted furrows; 2) use of an automated control system to vary application set times; and 3) cutback irrigation. Although this represents only a limited assessment of the alternatives that might be considered for the study area, preliminary results suggest that under certain field conditions irrigation efficiency can potentially improve more then 20% over the base condition using alternate strategies. The system demonstrated tremendous potential for identifying trends and variability in system performance in the region. Close

• 30. [Article] Successful onion irrigation scheduling

  Published September 2010. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/cat...

  Citation × Citation Citation Abstract Copy Title: Successful onion irrigation scheduling Author: Klauzer, Jim, Feibert, Erik Bruno Goncalves, Oregon State University. Extension Service, Shock, C. C. (Clinton C.), Jensen, Lynn Published September 2010. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: Successful onion irrigation scheduling Author: Klauzer, Jim, Feibert, Erik Bruno Goncalves, Oregon State University. Extension Service, Shock, C. C. (Clinton C.), Jensen, Lynn Published September 2010. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close

• 31. [Article] Relationships between degree of ponding and uniformity of soil moisture distribution under irrigation sprinklers

  Often low intake rate soils need special consideration when applying water during an irrigation. Surface flooding for extended periods may cause adverse crop growth conditions. Properly designed sprinkler ...

  Citation × Citation Citation Abstract Copy Title: Relationships between degree of ponding and uniformity of soil moisture distribution under irrigation sprinklers Author: Dehlinger, Charles Robert Often low intake rate soils need special consideration when applying water during an irrigation. Surface flooding for extended periods may cause adverse crop growth conditions. Properly designed sprinkler systems often eliminate irrigation problems, because the application rate and quantity of water applied can be readily controlled. Research workers who have studied sprinkler irrigation disagree on many things. Differences are found in the literature concerning the procedures used to determine sprinkler distribution uniformity and the optimum rate of application of water to the soil. Several authors suggest that moisture movement within the soil occurs after an irrigation. If trans location of moisture occurs, it may be possible to use sprinkler system design specifications that are less critical than those now in use. In order to determine the effect of sprinkler application rate on the resulting soil moisture distribution it is necessary to have criteria relating degree of ponding, crop cover, and slope of the land to the uniformity of soil moisture. Experimental plots were designed and prepared to study and relate these factors to each other. Sprinkler distribution measurements were made to be used in computing sprinkler uniformity. Using neutron equipment, soil moisture determinations were made before the irrigation, one day after irrigation, and three days after irrigation to determine the effect of the irrigation. Final analysis of the data from the experiment indicated that there was not an optimum degree of ponding. In fact, ponding, application rate, grade of plots, and crop cover did not appear to appreciably affect the distribution of soil moisture after an irrigation. Title: Relationships between degree of ponding and uniformity of soil moisture distribution under irrigation sprinklers Author: Dehlinger, Charles Robert Often low intake rate soils need special consideration when applying water during an irrigation. Surface flooding for extended periods may cause adverse crop growth conditions. Properly designed sprinkler systems often eliminate irrigation problems, because the application rate and quantity of water applied can be readily controlled. Research workers who have studied sprinkler irrigation disagree on many things. Differences are found in the literature concerning the procedures used to determine sprinkler distribution uniformity and the optimum rate of application of water to the soil. Several authors suggest that moisture movement within the soil occurs after an irrigation. If trans location of moisture occurs, it may be possible to use sprinkler system design specifications that are less critical than those now in use. In order to determine the effect of sprinkler application rate on the resulting soil moisture distribution it is necessary to have criteria relating degree of ponding, crop cover, and slope of the land to the uniformity of soil moisture. Experimental plots were designed and prepared to study and relate these factors to each other. Sprinkler distribution measurements were made to be used in computing sprinkler uniformity. Using neutron equipment, soil moisture determinations were made before the irrigation, one day after irrigation, and three days after irrigation to determine the effect of the irrigation. Final analysis of the data from the experiment indicated that there was not an optimum degree of ponding. In fact, ponding, application rate, grade of plots, and crop cover did not appear to appreciably affect the distribution of soil moisture after an irrigation. Close

• 32. [Article] Transitional Effects of Double-lateral Drip Irrigation and Straw Mulch on Irrigation Water Consumption, Mineral Nutrition, Yield, and Storability of Sweet Cherry

  This is a scanned version of a published article. The original can be found at: http://horttech.ashspublications.org/. To the best of our knowledge, one or more authors of this paper were federal employees ...

  Citation × Citation Citation Abstract Copy Title: Transitional Effects of Double-lateral Drip Irrigation and Straw Mulch on Irrigation Water Consumption, Mineral Nutrition, Yield, and Storability of Sweet Cherry Author: le Roux, Jac, Bai, Jinhe, Yin, Xinhua, Huang, Xiao-Lan, Long, Lynn E., Seavert, Clark F., Jaja, Ngowari This is a scanned version of a published article. The original can be found at: http://horttech.ashspublications.org/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Title: Transitional Effects of Double-lateral Drip Irrigation and Straw Mulch on Irrigation Water Consumption, Mineral Nutrition, Yield, and Storability of Sweet Cherry Author: le Roux, Jac, Bai, Jinhe, Yin, Xinhua, Huang, Xiao-Lan, Long, Lynn E., Seavert, Clark F., Jaja, Ngowari This is a scanned version of a published article. The original can be found at: http://horttech.ashspublications.org/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Close

• 33. [Article] Using infrared canopy temperature and leaf water potential for irrigation scheduling in peppermint (Mentha piperita L.)

  Several methods of infering plant water stress for irrigation scheduling are based upon measurements of the environment in which the plants grow. These measurements include parameters such as soil water ...

  Citation × Citation Citation Abstract Copy Title: Using infrared canopy temperature and leaf water potential for irrigation scheduling in peppermint (Mentha piperita L.) Author: Gallardo, Ivan T. Several methods of infering plant water stress for irrigation scheduling are based upon measurements of the environment in which the plants grow. These measurements include parameters such as soil water content, air temperature, pan evaporation and incident radiation. It is hypothesized that improved estimates of plant water deficit can be obtained by direct measurements made on the plants. The main objective of this study was to test the performance of measurements of canopy temperature and leaf water potential for irrigation scheduling. This study seeks to establish whether a correlation exists between these monitoring methods and measurements of soil moisture content, leaf area, and evapotranspiration. The experiments were conducted in first-year peppermint irrigated at five different rates. Canopy and air temperatures were measured with a hand-held infrared thermometer. Leaf water potential was measured with a pressure bomb. A non-stressed baseline for the difference between canopy temperature and air temperature using data from well-watered plants was used together with the vapor pressure deficit to determine the crop water stress index (CWSI). The results of this study show that the CWSI is well correlated to evapotranspiration deficit and is useful for irrigation scheduling. The relationship between leaf area yield and CWSI in peppermint was described by a quadratic function. Leaf water potential varied during the day in such a way that it was not possible to establish a relationship with water stress, differences in soil moisture content, or different irrigation levels. Leaf water potential was influenced by the daily weather conditions and represented the current demand more than the cumulative demand. The results of this study indicate that mid-day pressure bomb measurements cannot be used in irrigation scheduling. Predawn measurements of leaf water potential were stable, were well correlated with the different irrigation levels and soil moisture content, and therefore may be useful in irrigation scheduling. Title: Using infrared canopy temperature and leaf water potential for irrigation scheduling in peppermint (Mentha piperita L.) Author: Gallardo, Ivan T. Several methods of infering plant water stress for irrigation scheduling are based upon measurements of the environment in which the plants grow. These measurements include parameters such as soil water content, air temperature, pan evaporation and incident radiation. It is hypothesized that improved estimates of plant water deficit can be obtained by direct measurements made on the plants. The main objective of this study was to test the performance of measurements of canopy temperature and leaf water potential for irrigation scheduling. This study seeks to establish whether a correlation exists between these monitoring methods and measurements of soil moisture content, leaf area, and evapotranspiration. The experiments were conducted in first-year peppermint irrigated at five different rates. Canopy and air temperatures were measured with a hand-held infrared thermometer. Leaf water potential was measured with a pressure bomb. A non-stressed baseline for the difference between canopy temperature and air temperature using data from well-watered plants was used together with the vapor pressure deficit to determine the crop water stress index (CWSI). The results of this study show that the CWSI is well correlated to evapotranspiration deficit and is useful for irrigation scheduling. The relationship between leaf area yield and CWSI in peppermint was described by a quadratic function. Leaf water potential varied during the day in such a way that it was not possible to establish a relationship with water stress, differences in soil moisture content, or different irrigation levels. Leaf water potential was influenced by the daily weather conditions and represented the current demand more than the cumulative demand. The results of this study indicate that mid-day pressure bomb measurements cannot be used in irrigation scheduling. Predawn measurements of leaf water potential were stable, were well correlated with the different irrigation levels and soil moisture content, and therefore may be useful in irrigation scheduling. Close

• 34. [Article] Deficit Irrigation of Cabernet Sauvignon and Tempranillo: Impacts on Vine Growth, Yield, and Berry Composition

  Due to various reasons the previous investigator decided to pull out the crop level trials from the original experiment designed in 2010 season. However, the irrigation field experiments implemented in ...

  Citation × Citation Citation Abstract Copy Title: Deficit Irrigation of Cabernet Sauvignon and Tempranillo: Impacts on Vine Growth, Yield, and Berry Composition Author: Balint, Gabriel Due to various reasons the previous investigator decided to pull out the crop level trials from the original experiment designed in 2010 season. However, the irrigation field experiments implemented in the 2010 season continued in 2011, in order to find out the impact of varied deficit irrigation regimes on vine development and fruit composition in Tempranillo and Cabernet Sauvignon cultivars. Title: Deficit Irrigation of Cabernet Sauvignon and Tempranillo: Impacts on Vine Growth, Yield, and Berry Composition Author: Balint, Gabriel Due to various reasons the previous investigator decided to pull out the crop level trials from the original experiment designed in 2010 season. However, the irrigation field experiments implemented in the 2010 season continued in 2011, in order to find out the impact of varied deficit irrigation regimes on vine development and fruit composition in Tempranillo and Cabernet Sauvignon cultivars. Close

• 35. [Article] Evaluation of models for estimating surface irrigation infiltration parameters : data protocols and algorithm performance

  Citation × Citation Citation Abstract Copy Title: Evaluation of models for estimating surface irrigation infiltration parameters : data protocols and algorithm performance Author: Isbell, Sarah A. Title: Evaluation of models for estimating surface irrigation infiltration parameters : data protocols and algorithm performance Author: Isbell, Sarah A. Close

• 36. [Article] The value of irrigation water varies enormously across the Upper Klamath Basin

  Published January 2004. Reviewed January 2012. Please check for active titles in the OSU Extension Service website: http://extension.oregonstate.edu/catalog

  Citation × Citation Citation Abstract Copy Title: The value of irrigation water varies enormously across the Upper Klamath Basin Author: Jaeger, William K. (William Kenneth), Oregon State University. Extension Service Published January 2004. Reviewed January 2012. Please check for active titles in the OSU Extension Service website: http://extension.oregonstate.edu/catalog Title: The value of irrigation water varies enormously across the Upper Klamath Basin Author: Jaeger, William K. (William Kenneth), Oregon State University. Extension Service Published January 2004. Reviewed January 2012. Please check for active titles in the OSU Extension Service website: http://extension.oregonstate.edu/catalog Close

• 37. [Article] Drip irrigation guide for potatoes in the Treasure Valley

  Published October 2006. Reviewed March 2012. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog

  Citation × Citation Citation Abstract Copy Title: Drip irrigation guide for potatoes in the Treasure Valley Author: Flock, R., Pereira, A., Jensen, L., Eldredge, E., Oregon State University. Extension Service, Shock, C. C. (Clinton C.) Published October 2006. Reviewed March 2012. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: Drip irrigation guide for potatoes in the Treasure Valley Author: Flock, R., Pereira, A., Jensen, L., Eldredge, E., Oregon State University. Extension Service, Shock, C. C. (Clinton C.) Published October 2006. Reviewed March 2012. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close

• 38. [Article] Oregon crop water use and irrigation requirements

  Published June 1992. Reviewed July 2016. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog

  Citation × Citation Citation Abstract Copy Title: Oregon crop water use and irrigation requirements Author: Cuenca, Richard H., 1947-, Oregon State University. Extension Service Published June 1992. Reviewed July 2016. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: Oregon crop water use and irrigation requirements Author: Cuenca, Richard H., 1947-, Oregon State University. Extension Service Published June 1992. Reviewed July 2016. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close

• 39. [Article] Effect of irrigation level, insecticide and variety on root rot and yield of sweet corn: Research report to the Agricultural Research Foundation and the Oregon Processed Vegetable Commission, 2005

  Summary Irrigation effects on root rot and yield  Reducing irrigation during the first 6 weeks after planting reduced root rot of sweet corn at midseason and at harvest, consistent with findings of the ...

  Citation × Citation Citation Abstract Copy Title: Effect of irrigation level, insecticide and variety on root rot and yield of sweet corn: Research report to the Agricultural Research Foundation and the Oregon Processed Vegetable Commission, 2005 Author: Peachey, Ed Summary Irrigation effects on root rot and yield  Reducing irrigation during the first 6 weeks after planting reduced root rot of sweet corn at midseason and at harvest, consistent with findings of the past two years.  Reducing the early season irrigation level increased yield of Jubilee by 20% because of an increase in the number and size of ears produced. Insecticide effects  Vapam reduced midseason radicle root rot slightly.  The number of insect bites declined as the number of insecticides applied increased.  Insecticides had no effect on root rot at the Vegetable Research Farm, the site with greatest root rot levels. Insecticides may have increased root rot ratings at the Botany farm.  There was a positive but weak correlation (R=0.57) between insect damage to Jubilee roots and nodal root rot at the Vegetable Research Farm.  Insecticides may have increased yield of Coho (at both irrigation levels) and Jubilee (at the Low irrigation level) at the Vegetable Research Farm. Insecticides increased yield of all varieties in the Botany Farm experiment. Varietal effects  Yield of Coho was greater than Jubilee, Kokanee, and Chase at both sites. Coho yields were consistently High under stresses of root rot and insect damage. Title: Effect of irrigation level, insecticide and variety on root rot and yield of sweet corn: Research report to the Agricultural Research Foundation and the Oregon Processed Vegetable Commission, 2005 Author: Peachey, Ed Summary Irrigation effects on root rot and yield  Reducing irrigation during the first 6 weeks after planting reduced root rot of sweet corn at midseason and at harvest, consistent with findings of the past two years.  Reducing the early season irrigation level increased yield of Jubilee by 20% because of an increase in the number and size of ears produced. Insecticide effects  Vapam reduced midseason radicle root rot slightly.  The number of insect bites declined as the number of insecticides applied increased.  Insecticides had no effect on root rot at the Vegetable Research Farm, the site with greatest root rot levels. Insecticides may have increased root rot ratings at the Botany farm.  There was a positive but weak correlation (R=0.57) between insect damage to Jubilee roots and nodal root rot at the Vegetable Research Farm.  Insecticides may have increased yield of Coho (at both irrigation levels) and Jubilee (at the Low irrigation level) at the Vegetable Research Farm. Insecticides increased yield of all varieties in the Botany Farm experiment. Varietal effects  Yield of Coho was greater than Jubilee, Kokanee, and Chase at both sites. Coho yields were consistently High under stresses of root rot and insect damage. Close

• 40. [Article] Descriptive analysis of two consecutive vintages of Oregon Pinot noir wines as effected by irrigation, tillage and nitrogen supplementation in the vineyard

  Two vintages of Vitis vinifera cv. Pinot noir wine from a viticulture trial evaluating nitrogen fertilization, tilling and irrigation underwent descriptive analysis using a modified version of free-choice ...

  Citation × Citation Citation Abstract Copy Title: Descriptive analysis of two consecutive vintages of Oregon Pinot noir wines as effected by irrigation, tillage and nitrogen supplementation in the vineyard Author: Hjorth, Heather Byrne Two vintages of Vitis vinifera cv. Pinot noir wine from a viticulture trial evaluating nitrogen fertilization, tilling and irrigation underwent descriptive analysis using a modified version of free-choice profiling. Wines were made from three field blocks of the twelve factorial combinations of Irrigation (Dry or Irrigated), Tillage (Tilled or not Tilled) and Fertilization (None, Foliar nitrogen supplementation or soil applied nitrogen). Irrigation was associated with lower anthocyanins and total phenols as well as lower color intensity and purple hue in both vintages. Irrigation increased vegetative and spicy character in the 1999 vintage while non-irrigated treatments were characterized by fruit, cherry and berry characteristics. Tilling significantly increased fruity flavor and body in the 1999 vintage and was associated with increased vegetative character in the 2000 vintage. In the 2000 vintage, non-fertilized treatments were significantly higher in floral aroma than the soil or foliar fertilized treatments. Title: Descriptive analysis of two consecutive vintages of Oregon Pinot noir wines as effected by irrigation, tillage and nitrogen supplementation in the vineyard Author: Hjorth, Heather Byrne Two vintages of Vitis vinifera cv. Pinot noir wine from a viticulture trial evaluating nitrogen fertilization, tilling and irrigation underwent descriptive analysis using a modified version of free-choice profiling. Wines were made from three field blocks of the twelve factorial combinations of Irrigation (Dry or Irrigated), Tillage (Tilled or not Tilled) and Fertilization (None, Foliar nitrogen supplementation or soil applied nitrogen). Irrigation was associated with lower anthocyanins and total phenols as well as lower color intensity and purple hue in both vintages. Irrigation increased vegetative and spicy character in the 1999 vintage while non-irrigated treatments were characterized by fruit, cherry and berry characteristics. Tilling significantly increased fruity flavor and body in the 1999 vintage and was associated with increased vegetative character in the 2000 vintage. In the 2000 vintage, non-fertilized treatments were significantly higher in floral aroma than the soil or foliar fertilized treatments. Close

• 41. [Article] A farm-level economic analysis of water-conserving irrigation systems and commercial agricultural water transfers to instream flows in central Oregon

  The middle Deschutes River between Bend, Oregon and Lake Billy Chinook typically experiences critically low flows during the irrigation season. Commercial agriculture in the North Unit Irrigation District ...

  Citation × Citation Citation Abstract Copy Title: A farm-level economic analysis of water-conserving irrigation systems and commercial agricultural water transfers to instream flows in central Oregon Author: Turner, Brenda The middle Deschutes River between Bend, Oregon and Lake Billy Chinook typically experiences critically low flows during the irrigation season. Commercial agriculture in the North Unit Irrigation District and Central Oregon Irrigation District is one major user of Deschutes River water. The overall objective of this research was to estimate the cost to transfer water from commercial agriculture operations to instream flow use assuming a water market existed. Two methods of providing water within commercial agriculture were considered; 1) lining irrigation district canals that supply water to farms and 2) changing on-farm water use. On-farm practices include adopting water conserving irrigation technologies and involvement in Oregon's water conservation program. Supply curves were generated for these alternatives assuming expected and alternative streamfiow levels. Results indicated that changing crop rotations, adopting water conserving technologies and participating in Oregon's conservation program were used, depending on the market price for water. Canal lining, however, was generally the most cost-effective means of providing water to enhance flows in the middle Deschutes River. Title: A farm-level economic analysis of water-conserving irrigation systems and commercial agricultural water transfers to instream flows in central Oregon Author: Turner, Brenda The middle Deschutes River between Bend, Oregon and Lake Billy Chinook typically experiences critically low flows during the irrigation season. Commercial agriculture in the North Unit Irrigation District and Central Oregon Irrigation District is one major user of Deschutes River water. The overall objective of this research was to estimate the cost to transfer water from commercial agriculture operations to instream flow use assuming a water market existed. Two methods of providing water within commercial agriculture were considered; 1) lining irrigation district canals that supply water to farms and 2) changing on-farm water use. On-farm practices include adopting water conserving irrigation technologies and involvement in Oregon's water conservation program. Supply curves were generated for these alternatives assuming expected and alternative streamfiow levels. Results indicated that changing crop rotations, adopting water conserving technologies and participating in Oregon's conservation program were used, depending on the market price for water. Canal lining, however, was generally the most cost-effective means of providing water to enhance flows in the middle Deschutes River. Close

• 42. [Article] Effect of nitrogen fertilizer and irrigation on Acacia senegal seedling biomass and photosynthesis

  Seedlings of Acacia senegal were grown in a glass greenhouse to study the effect of nitrogen and irrigation regimes on dry matter production and allocation to different plant organs, net photosynthesis ...

  Citation × Citation Citation Abstract Copy Title: Effect of nitrogen fertilizer and irrigation on Acacia senegal seedling biomass and photosynthesis Author: Warrag, Esam Eldin I. Seedlings of Acacia senegal were grown in a glass greenhouse to study the effect of nitrogen and irrigation regimes on dry matter production and allocation to different plant organs, net photosynthesis per unit leaf area, and nitrogen content in the different plant organs. Ammonium nitrate (NH4NO3) was used in this study, as the source of inorganic nitrogen. The nitrogen treatment consisted of four levels: 0, 30, 100, and 200 ppm of N which were added with the irrigation solution. Irrigation treatment consisted of irrigation every two, five or ten days. Nitrogen fertilization, irrigation regimes, and their interaction significantly affect the total stem, root, and leaf dry weight. However, low and moderate levels of N with irrigation every two days, resulted in higher total plant dry weight. Contrary to the initial hypothesis of the study, net photosynthesis showed no significant differences among the N treatments, but a decrease occurred after the fifth day since irrigation; this was also followed by a low net CO2 uptake. Stomatal conductance was affected significantly by the N and irrigation treatments. Total N content in the whole seedlings, stems, roots, and leaves was found to be high at low to moderate application of N, with irrigation every two days, while percent N in these parts showed a marked increase with increasing the N added. Moreover, percent N in roots showed the highest increase compared to percent N in stems and leaves. Title: Effect of nitrogen fertilizer and irrigation on Acacia senegal seedling biomass and photosynthesis Author: Warrag, Esam Eldin I. Seedlings of Acacia senegal were grown in a glass greenhouse to study the effect of nitrogen and irrigation regimes on dry matter production and allocation to different plant organs, net photosynthesis per unit leaf area, and nitrogen content in the different plant organs. Ammonium nitrate (NH4NO3) was used in this study, as the source of inorganic nitrogen. The nitrogen treatment consisted of four levels: 0, 30, 100, and 200 ppm of N which were added with the irrigation solution. Irrigation treatment consisted of irrigation every two, five or ten days. Nitrogen fertilization, irrigation regimes, and their interaction significantly affect the total stem, root, and leaf dry weight. However, low and moderate levels of N with irrigation every two days, resulted in higher total plant dry weight. Contrary to the initial hypothesis of the study, net photosynthesis showed no significant differences among the N treatments, but a decrease occurred after the fifth day since irrigation; this was also followed by a low net CO2 uptake. Stomatal conductance was affected significantly by the N and irrigation treatments. Total N content in the whole seedlings, stems, roots, and leaves was found to be high at low to moderate application of N, with irrigation every two days, while percent N in these parts showed a marked increase with increasing the N added. Moreover, percent N in roots showed the highest increase compared to percent N in stems and leaves. Close

• 43. [Article] Shallow Aquifer Recharge from Irrigation in a Semi-arid Agricultural Valley in New Mexico, USA

  This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the American Society of Civil Engineers and can be found at: http://cedb.asce.o...

  Citation × Citation Citation Abstract Copy Title: Shallow Aquifer Recharge from Irrigation in a Semi-arid Agricultural Valley in New Mexico, USA Author: Ochoa, Carlos G., Shukla, Manoj K., Guldan, Steven J., Fernald, Alexander G., Tidwell, Vincent C. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the American Society of Civil Engineers and can be found at: http://cedb.asce.org/cgi/WWWdisplay.cgi?310565. Title: Shallow Aquifer Recharge from Irrigation in a Semi-arid Agricultural Valley in New Mexico, USA Author: Ochoa, Carlos G., Shukla, Manoj K., Guldan, Steven J., Fernald, Alexander G., Tidwell, Vincent C. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the American Society of Civil Engineers and can be found at: http://cedb.asce.org/cgi/WWWdisplay.cgi?310565. Close

• 44. [Article] Irrigation Frequency Alters Nutrient Uptake in Container-grown Rhododendron Plants Grown with Different Rates of Nitrogen

  The influence of irrigation frequency (same amount of water per day given at different times) on nutrient uptake of container-grown evergreen Rhododendron ‘P.J.M. Compact’ (PJM) and ‘English Roseum’ (ER) ...

  Citation × Citation Citation Abstract Copy Title: Irrigation Frequency Alters Nutrient Uptake in Container-grown Rhododendron Plants Grown with Different Rates of Nitrogen Author: Regan, Richard P., Bi, Guihong, Scagel, Carolyn F., Fuchigami, Leslie H. The influence of irrigation frequency (same amount of water per day given at different times) on nutrient uptake of container-grown evergreen Rhododendron ‘P.J.M. Compact’ (PJM) and ‘English Roseum’ (ER) and deciduous Rhododendron ‘Gibraltar’ (AZ) grown with different rates of nitrogen (N) fertilizer was evaluated. Increased N application rate increased nutrient uptake and plant dry biomass. Irrigation frequency did not significantly influence total plant dry biomass; however, more frequent irrigation decreased net uptake of several nutrients including phosphorus (P), boron (B), and manganese (Mn) uptake in all cultivars; potassium (K), copper (Cu), and zinc (Zn) uptake in AZ and ER; sulfur (S) uptake in ER and PJM; and iron (Fe) uptake in AZ. Additionally, more frequent irrigation of evergreen cultivars increased calcium (Ca) uptake. Covariate analyses were used to compare nutrient uptake among cultivars and irrigation treatments after accounting for the variability in nutrient uptake attributable to differences in biomass and N uptake. For most nutrients, the influence of irrigation frequency on uptake was partially attributable to differences in biomass and N uptake. After accounting for the variability in nutrient uptake associated with biomass or N uptake, increased irrigation frequency decreased P, S, B, Cu, and Mn uptake only in ER and increased Ca uptake in the two evergreen cultivars. Differences in nutrient uptake among cultivars in response to irrigation treatments were related to water and N availability during production and their combined influence on water stress, nutrient uptake, and biomass partitioning. Estimates of nutrient demand and uptake efficiency using nutrient concentrations and ratios are discussed in relation to nutrient management differences for different cultivars and irrigation treatments. Title: Irrigation Frequency Alters Nutrient Uptake in Container-grown Rhododendron Plants Grown with Different Rates of Nitrogen Author: Regan, Richard P., Bi, Guihong, Scagel, Carolyn F., Fuchigami, Leslie H. The influence of irrigation frequency (same amount of water per day given at different times) on nutrient uptake of container-grown evergreen Rhododendron ‘P.J.M. Compact’ (PJM) and ‘English Roseum’ (ER) and deciduous Rhododendron ‘Gibraltar’ (AZ) grown with different rates of nitrogen (N) fertilizer was evaluated. Increased N application rate increased nutrient uptake and plant dry biomass. Irrigation frequency did not significantly influence total plant dry biomass; however, more frequent irrigation decreased net uptake of several nutrients including phosphorus (P), boron (B), and manganese (Mn) uptake in all cultivars; potassium (K), copper (Cu), and zinc (Zn) uptake in AZ and ER; sulfur (S) uptake in ER and PJM; and iron (Fe) uptake in AZ. Additionally, more frequent irrigation of evergreen cultivars increased calcium (Ca) uptake. Covariate analyses were used to compare nutrient uptake among cultivars and irrigation treatments after accounting for the variability in nutrient uptake attributable to differences in biomass and N uptake. For most nutrients, the influence of irrigation frequency on uptake was partially attributable to differences in biomass and N uptake. After accounting for the variability in nutrient uptake associated with biomass or N uptake, increased irrigation frequency decreased P, S, B, Cu, and Mn uptake only in ER and increased Ca uptake in the two evergreen cultivars. Differences in nutrient uptake among cultivars in response to irrigation treatments were related to water and N availability during production and their combined influence on water stress, nutrient uptake, and biomass partitioning. Estimates of nutrient demand and uptake efficiency using nutrient concentrations and ratios are discussed in relation to nutrient management differences for different cultivars and irrigation treatments. Close

• 45. [Article] Irrigation Decisions for Major West Coast Crops: Water Scarcity and Climatic Determinants

  Access to this item has been restricted by repository administrators at the request of the publisher, Oxford University Press, until June 15, 2017.

  Citation × Citation Citation Abstract Copy Title: Irrigation Decisions for Major West Coast Crops: Water Scarcity and Climatic Determinants Author: Olen, Beau, Wu, JunJie, Langpap, Christian Access to this item has been restricted by repository administrators at the request of the publisher, Oxford University Press, until June 15, 2017. Title: Irrigation Decisions for Major West Coast Crops: Water Scarcity and Climatic Determinants Author: Olen, Beau, Wu, JunJie, Langpap, Christian Access to this item has been restricted by repository administrators at the request of the publisher, Oxford University Press, until June 15, 2017. Close

• 46. [Article] An Engineers Approach to Irrigation Management in Oregon Pinot noir

  Vineyard managers must decide on the timing and amount of irrigation. In Oregon the need for irrigation differs greatly year to year and field to field based on micro climate, soil, root development, plant ...

  Citation × Citation Citation Abstract Copy Title: An Engineers Approach to Irrigation Management in Oregon Pinot noir Author: Selker, John, Baer, Emilie Vineyard managers must decide on the timing and amount of irrigation. In Oregon the need for irrigation differs greatly year to year and field to field based on micro climate, soil, root development, plant health, and root stock. We suggest the use of leaf water potential as a useful management tool. We show that for this test to provide consistent values, leaves should be wrapped prior to removal, should have consistent solar exposure, but need not have precisely the same age. We illustrate the use of this measure with data from the 2001 growing season taken in two Willamette valley fields. The data showed that irrigation was not required throughout the season, and helps explain the unexpectedly high yields noted by the vineyards. Title: An Engineers Approach to Irrigation Management in Oregon Pinot noir Author: Selker, John, Baer, Emilie Vineyard managers must decide on the timing and amount of irrigation. In Oregon the need for irrigation differs greatly year to year and field to field based on micro climate, soil, root development, plant health, and root stock. We suggest the use of leaf water potential as a useful management tool. We show that for this test to provide consistent values, leaves should be wrapped prior to removal, should have consistent solar exposure, but need not have precisely the same age. We illustrate the use of this measure with data from the 2001 growing season taken in two Willamette valley fields. The data showed that irrigation was not required throughout the season, and helps explain the unexpectedly high yields noted by the vineyards. Close

• 47. [Article] Irrigating peppermint

  Declared out of print March 2010. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate...

  Citation × Citation Citation Abstract Copy Title: Irrigating peppermint Author: Mitchell, Alan R., Oregon State University. Extension Service Declared out of print March 2010. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: Irrigating peppermint Author: Mitchell, Alan R., Oregon State University. Extension Service Declared out of print March 2010. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close

• 48. [Article] Strategies for efficient irrigation water use

  Published July 2001. Revised March 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog

  Citation × Citation Citation Abstract Copy Title: Strategies for efficient irrigation water use Author: Shock, B. M., Oregon State University. Extension Service, Shock, C. C. (Clinton C.), Welch, Teresa Published July 2001. Revised March 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: Strategies for efficient irrigation water use Author: Shock, B. M., Oregon State University. Extension Service, Shock, C. C. (Clinton C.), Welch, Teresa Published July 2001. Revised March 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close

• 49. [Article] Drip irrigation guide for onion growers

  Published December 2005. Revised January 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog

  Citation × Citation Citation Abstract Copy Title: Drip irrigation guide for onion growers Author: Shock, Cedric A., Feibert, Erik Bruno Goncalves, Flock, Rebecca, Oregon State University. Extension Service, Shock, C. C. (Clinton C.) Published December 2005. Revised January 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: Drip irrigation guide for onion growers Author: Shock, Cedric A., Feibert, Erik Bruno Goncalves, Flock, Rebecca, Oregon State University. Extension Service, Shock, C. C. (Clinton C.) Published December 2005. Revised January 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close

• 50. [Article] Drip irrigation guide for growers of hybrid poplar

  Published December 2005. Revised January 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog

  Citation × Citation Citation Abstract Copy Title: Drip irrigation guide for growers of hybrid poplar Author: Pereira, Andre, O'Neill, Mick, Feibert, Erik Bruno Goncalves, Flock, Rebecca, Oregon State University. Extension Service, Shock, C. C. (Clinton C.) Published December 2005. Revised January 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: Drip irrigation guide for growers of hybrid poplar Author: Pereira, Andre, O'Neill, Mick, Feibert, Erik Bruno Goncalves, Flock, Rebecca, Oregon State University. Extension Service, Shock, C. C. (Clinton C.) Published December 2005. Revised January 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close