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• 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