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• 1. [Article] Cranberries (south coastal Oregon)

  Published July 1997. A more recent revision exists. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://ex...

  Citation × Citation Citation Abstract Copy Title: Cranberries (south coastal Oregon) Author: Strik, B., Hart, J., Righetti, T., Oregon State University. Extension Service, Poole, Art Published July 1997. A more recent revision exists. 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: Cranberries (south coastal Oregon) Author: Strik, B., Hart, J., Righetti, T., Oregon State University. Extension Service, Poole, Art Published July 1997. A more recent revision exists. 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

• 2. [Article] Monitoring of Soil Moisture: Methods, Improving Wine Quality and Extent of Wetting

  Interim Progress Report to the Wine Advisory Board, Agricultural Research Foundation, and Participating Growers

  Citation × Citation Citation Abstract Copy Title: Monitoring of Soil Moisture: Methods, Improving Wine Quality and Extent of Wetting Author: Rojas, Wilson, Selker, John, Candolfi-Vasconcelos, M. Carmo Interim Progress Report to the Wine Advisory Board, Agricultural Research Foundation, and Participating Growers Title: Monitoring of Soil Moisture: Methods, Improving Wine Quality and Extent of Wetting Author: Rojas, Wilson, Selker, John, Candolfi-Vasconcelos, M. Carmo Interim Progress Report to the Wine Advisory Board, Agricultural Research Foundation, and Participating Growers Close

• 3. [Article] A genetic linkage map of black raspberry (Rubus occidentalis) and the mapping of Ag (4) conferring resistance to the aphid Amphorophora agathonica

  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 Springer ...

  Citation × Citation Citation Abstract Copy Title: A genetic linkage map of black raspberry (Rubus occidentalis) and the mapping of Ag (4) conferring resistance to the aphid Amphorophora agathonica Author: Finn, Chad E., Lee, Jungmin, VanBuren, Robert, Bassil, Nahla V., Bryant, Douglas W., Gilmore, Barbara S., Dossett, Michael, Mockler, Todd C., Vining, Kelly J., Bushakra, Jill M. 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 Springer and can be found at: http://link.springer.com/journal/122 Title: A genetic linkage map of black raspberry (Rubus occidentalis) and the mapping of Ag (4) conferring resistance to the aphid Amphorophora agathonica Author: Finn, Chad E., Lee, Jungmin, VanBuren, Robert, Bassil, Nahla V., Bryant, Douglas W., Gilmore, Barbara S., Dossett, Michael, Mockler, Todd C., Vining, Kelly J., Bushakra, Jill M. 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 Springer and can be found at: http://link.springer.com/journal/122 Close

• 4. [Article] Onion Thrips (Thysanoptera: Thripidae) and Their Management in the Treasure Valley of the Pacific Northwest

  Onion thrips, Thrips tabaci Lindeman and thrips-transmitted Iris yellow spot virus are the most significant pest complex affecting onion production in the Treasure Valley of eastern Oregon and southwestern ...

  Citation × Citation Citation Abstract Copy Title: Onion Thrips (Thysanoptera: Thripidae) and Their Management in the Treasure Valley of the Pacific Northwest Author: Reitz, Stuart R. Onion thrips, Thrips tabaci Lindeman and thrips-transmitted Iris yellow spot virus are the most significant pest complex affecting onion production in the Treasure Valley of eastern Oregon and southwestern Idaho. Thrips feeding damage and virus infection significantly reduce onion bulb size and economic returns for this high value crop. The high concentration of onion fields in the Treasure Valley and the long, hot, dry growing season present a number of challenges for managing onion thrips and Iris yellow spot virus (IYSV). Insecticides are the primary tool that growers have to manage this pest complex. With the long growing season, growers need to exercise good insecticide resistance management programs to maintain the effectiveness of currently available insecticides. To do this, growers need to rotate among available products and use as few applications as practical. A challenge for researchers is to determine not only which insecticides are effective but also to determine when during the season different products may be most effectively used. Techniques for analyzing field trial data are discussed, including comparing changes in pest populations before and after various insecticide applications are made. These comparisons can be made through the use of linear estimates and contrasts as part of analyses of variance, and they can aid in determining efficacy of different treatments by accounting for pre-application populations. These techniques will help researchers in developing sound sequence of insecticide applications for onion thrips management. Title: Onion Thrips (Thysanoptera: Thripidae) and Their Management in the Treasure Valley of the Pacific Northwest Author: Reitz, Stuart R. Onion thrips, Thrips tabaci Lindeman and thrips-transmitted Iris yellow spot virus are the most significant pest complex affecting onion production in the Treasure Valley of eastern Oregon and southwestern Idaho. Thrips feeding damage and virus infection significantly reduce onion bulb size and economic returns for this high value crop. The high concentration of onion fields in the Treasure Valley and the long, hot, dry growing season present a number of challenges for managing onion thrips and Iris yellow spot virus (IYSV). Insecticides are the primary tool that growers have to manage this pest complex. With the long growing season, growers need to exercise good insecticide resistance management programs to maintain the effectiveness of currently available insecticides. To do this, growers need to rotate among available products and use as few applications as practical. A challenge for researchers is to determine not only which insecticides are effective but also to determine when during the season different products may be most effectively used. Techniques for analyzing field trial data are discussed, including comparing changes in pest populations before and after various insecticide applications are made. These comparisons can be made through the use of linear estimates and contrasts as part of analyses of variance, and they can aid in determining efficacy of different treatments by accounting for pre-application populations. These techniques will help researchers in developing sound sequence of insecticide applications for onion thrips management. Close

• 5. [Article] Aquaculture Certification and the Seafood Trade

  Abstract only.

  Citation × Citation Citation Abstract Copy Title: Aquaculture Certification and the Seafood Trade Author: Lee, Daniel Abstract only. Title: Aquaculture Certification and the Seafood Trade Author: Lee, Daniel Abstract only. Close

• 6. [Article] Experimental analysis of subsurface heating and irrigation on the temperature and water content of soils

  Multiple use of waste heat from power plants may become an important consideration in the development, siting, and certification of these plants. A multiple use system of components that can beneficially ...

  Citation × Citation Citation Abstract Copy Title: Experimental analysis of subsurface heating and irrigation on the temperature and water content of soils Author: Sepaskhah, Ali Reza Multiple use of waste heat from power plants may become an important consideration in the development, siting, and certification of these plants. A multiple use system of components that can beneficially utilize waste heat may include home heating and cooling, greenhouses, animal enclosures, open basins for single cell protein production and fish farming, and open field soil warming. A subsurface irrigation-soil warming system utilizing waste heat was analyzed in this study. Thermal power plant condenser cooling water pumped through buried porous pipes was considered as a heat and water source for soil heating and subsurface irrigation. Energy is transferred from the heat source to the surrounding soil, warming it above its natural temperature. In addition, water seeping from the porous pipe prevents drying around the heat source and supplies the plant roots throughout the soil profile while avoiding the large evaporation losses at the soil surface associated with surface irrigation methods. Experiments were conducted in the laboratory to study this system. Soil was packed in containers 48 cm deep, 40 cm wide, and 4 cm thick. A heat source consisting of a copper covered electrical resistance wire was placed against one side of the box at a depth of 32 cm. A water source consisting of a porous tube was placed 2 cm above the heat source. The contained soil slab thus represented a subsurface soil warming and irrigation system with heat and water sources at depths of 32 and 30 cm respectively and a 77 cm spacing. A series of experiments was conducted with heat source temperatures of 29, 36, and 44 C, and surface heat load cycles with maxima of 0, 13, 52, and 117 watts. These experiments were repeated for Quincy, Cloquato, and Chehalis soils. The box filled with soil was saturated with water and then drained. Experiments were initiated by energizing the heat source. Temperature distributions throughout the soil profile and rates of energy dissipation were measured. Water application rates required to maintain a constant soil water content were obtained. In each experiment, water was applied at such a rate that the water content at a point near the heat source, monitored with a gamma ray attenuation system, remained constant. Apparent thermal conductivities of Quincy, Cloquato, and Chehalis soils as a function of water content were measured at 25 and 45 C by the heat probe method. The soil apparent thermal conductivity was also computed from a theoretical model based on its mineral composition, porosity, water content, and the thermal conductivity of the individual components. This model takes into account the vapor flow contribution to the apparent thermal conductivity in wet soils. Its magnitude depends on the available air-filled pore space, total porosity, and the free energy of the retained water. Predicted and experimental values of thermal conductivities showed good agreement. Soil temperature distributions were calculated using theoretical models presented in the literature. Predicted and measured isotherms showed good agreement. Energy dissipation rates as a function of soil thermal conductivity, temperature differences between heat source and soil surface, and depth and spacing of heat source were obtained. They were in agreement with those calculated from theoretical considerations. The total land area required to dissipate the waste energy from a 1000 MWe power plant operating with 34 percent efficiency was calculated for each of the three soils used in the experiments. It was found that 2841, 3714, and 4390 hectare would be required for Quincy, Cloquato, and Chehalis soils respectively. Quincy soil would require the smallest land area for this purpose because of its higher thermal conductivity. Economical and technical considerations for the installation of subsurface heating and irrigation systems require flat land close to the electrical power plant. Large areas of flat land are not always present. Subsurface irrigation replenished water lost by surface evaporation. Water use rates were obtained as a function of temperature differences between heat source and soil surface, soil type, and a range of surface heat loads. The water application rates ranged from 1.50 mm/day for Chehalis soil with a heat source temperature of 29 C in combination with the lowest surface heat load to 6.0 mm/day for Quincy soil with a heat source temperature of 44 C in combination with the highest surface heat load. These rates were adequate to prevent drying around the heat sources and supply the water needs of an actively growing crop. The effective use of this system depends on the development of suitable tubing to conduct and discharge water which could be used without clogging of the pores through which water seeps into the ground. The proposed soil warming and irrigation system does not appear to be an attractive alternative power plant cooling system. The system holds promise however as an economically attractive management system for the production of high value crops. Title: Experimental analysis of subsurface heating and irrigation on the temperature and water content of soils Author: Sepaskhah, Ali Reza Multiple use of waste heat from power plants may become an important consideration in the development, siting, and certification of these plants. A multiple use system of components that can beneficially utilize waste heat may include home heating and cooling, greenhouses, animal enclosures, open basins for single cell protein production and fish farming, and open field soil warming. A subsurface irrigation-soil warming system utilizing waste heat was analyzed in this study. Thermal power plant condenser cooling water pumped through buried porous pipes was considered as a heat and water source for soil heating and subsurface irrigation. Energy is transferred from the heat source to the surrounding soil, warming it above its natural temperature. In addition, water seeping from the porous pipe prevents drying around the heat source and supplies the plant roots throughout the soil profile while avoiding the large evaporation losses at the soil surface associated with surface irrigation methods. Experiments were conducted in the laboratory to study this system. Soil was packed in containers 48 cm deep, 40 cm wide, and 4 cm thick. A heat source consisting of a copper covered electrical resistance wire was placed against one side of the box at a depth of 32 cm. A water source consisting of a porous tube was placed 2 cm above the heat source. The contained soil slab thus represented a subsurface soil warming and irrigation system with heat and water sources at depths of 32 and 30 cm respectively and a 77 cm spacing. A series of experiments was conducted with heat source temperatures of 29, 36, and 44 C, and surface heat load cycles with maxima of 0, 13, 52, and 117 watts. These experiments were repeated for Quincy, Cloquato, and Chehalis soils. The box filled with soil was saturated with water and then drained. Experiments were initiated by energizing the heat source. Temperature distributions throughout the soil profile and rates of energy dissipation were measured. Water application rates required to maintain a constant soil water content were obtained. In each experiment, water was applied at such a rate that the water content at a point near the heat source, monitored with a gamma ray attenuation system, remained constant. Apparent thermal conductivities of Quincy, Cloquato, and Chehalis soils as a function of water content were measured at 25 and 45 C by the heat probe method. The soil apparent thermal conductivity was also computed from a theoretical model based on its mineral composition, porosity, water content, and the thermal conductivity of the individual components. This model takes into account the vapor flow contribution to the apparent thermal conductivity in wet soils. Its magnitude depends on the available air-filled pore space, total porosity, and the free energy of the retained water. Predicted and experimental values of thermal conductivities showed good agreement. Soil temperature distributions were calculated using theoretical models presented in the literature. Predicted and measured isotherms showed good agreement. Energy dissipation rates as a function of soil thermal conductivity, temperature differences between heat source and soil surface, and depth and spacing of heat source were obtained. They were in agreement with those calculated from theoretical considerations. The total land area required to dissipate the waste energy from a 1000 MWe power plant operating with 34 percent efficiency was calculated for each of the three soils used in the experiments. It was found that 2841, 3714, and 4390 hectare would be required for Quincy, Cloquato, and Chehalis soils respectively. Quincy soil would require the smallest land area for this purpose because of its higher thermal conductivity. Economical and technical considerations for the installation of subsurface heating and irrigation systems require flat land close to the electrical power plant. Large areas of flat land are not always present. Subsurface irrigation replenished water lost by surface evaporation. Water use rates were obtained as a function of temperature differences between heat source and soil surface, soil type, and a range of surface heat loads. The water application rates ranged from 1.50 mm/day for Chehalis soil with a heat source temperature of 29 C in combination with the lowest surface heat load to 6.0 mm/day for Quincy soil with a heat source temperature of 44 C in combination with the highest surface heat load. These rates were adequate to prevent drying around the heat sources and supply the water needs of an actively growing crop. The effective use of this system depends on the development of suitable tubing to conduct and discharge water which could be used without clogging of the pores through which water seeps into the ground. The proposed soil warming and irrigation system does not appear to be an attractive alternative power plant cooling system. The system holds promise however as an economically attractive management system for the production of high value crops. Close

• 7. [Article] Predicting nitrate concentrations in leachate resulting from land application of wastewater onto various crop systems including poplars

  Land application of industrial wastewater with high levels of nitrogen requires adequate management practices to prevent groundwater pollution by nitrates. In this study a predictive computerized model ...

  Citation × Citation Citation Abstract Copy Title: Predicting nitrate concentrations in leachate resulting from land application of wastewater onto various crop systems including poplars Author: Motte, Marie Quitterie Land application of industrial wastewater with high levels of nitrogen requires adequate management practices to prevent groundwater pollution by nitrates. In this study a predictive computerized model was developed for nitrate leachate concentrations resulting from land application of wastewater onto crop systems including poplars. The study included a literature review, development of a computer program that could serve this purpose, and a field investigation to test the validity of the computed predictions. The literature review focused on poplar water and nitrogen uptakes, and suggested that mature poplars could uptake up to 400 lb of nitrogen /acre/year and 2 3 million gallons of water per acre per year. The computer model, based on 10-day water and nutrient balances, takes into account a number of parameters such as wastewater quality, evapotranspiration and precipitation data, irrigation volumes, soil water holding capacities, fertilization, crop nutrient uptakes and crop coefficients. This study involves a number of assumptions selected to give conservative (i.e., worst case approach) model predictions. Attempts to validate the model were conducted through soil and groundwater sampling along with precipitation data collection in four distinct fields in Brooks, Oregon, from October 1996 to April 1997. The variations in nitrogen soil profiles from October to April helped determine the amount of nitrogen leaving the soil, and groundwater samples from 5 feet deep wells gave nitrate concentrations in groundwater below the root zone. A sensitivity analysis of the program demonstrated how important nitrogen and water uptakes values were to the model predictions. An increase of 1% in nitrogen uptake or of 0.4% in crop coefficients generated 1% decrease in nitrogen concentration of the leachate. These results are important to consider when adopting highly uncertain literature values for crop uptakes -especially with poplars. The field validation of the model showed promising results in terms of estimating average yearly leachate concentrations in nitrogen resulting from land application of wastewater, but also suggested that more groundwater wells were needed to obtain a statistically significant validation of the model. These preliminary field results indicate that the model can provide an indication of groundwater nitrogen concentration trends but needs to further verified to be used confidently as a predictive tool. Title: Predicting nitrate concentrations in leachate resulting from land application of wastewater onto various crop systems including poplars Author: Motte, Marie Quitterie Land application of industrial wastewater with high levels of nitrogen requires adequate management practices to prevent groundwater pollution by nitrates. In this study a predictive computerized model was developed for nitrate leachate concentrations resulting from land application of wastewater onto crop systems including poplars. The study included a literature review, development of a computer program that could serve this purpose, and a field investigation to test the validity of the computed predictions. The literature review focused on poplar water and nitrogen uptakes, and suggested that mature poplars could uptake up to 400 lb of nitrogen /acre/year and 2 3 million gallons of water per acre per year. The computer model, based on 10-day water and nutrient balances, takes into account a number of parameters such as wastewater quality, evapotranspiration and precipitation data, irrigation volumes, soil water holding capacities, fertilization, crop nutrient uptakes and crop coefficients. This study involves a number of assumptions selected to give conservative (i.e., worst case approach) model predictions. Attempts to validate the model were conducted through soil and groundwater sampling along with precipitation data collection in four distinct fields in Brooks, Oregon, from October 1996 to April 1997. The variations in nitrogen soil profiles from October to April helped determine the amount of nitrogen leaving the soil, and groundwater samples from 5 feet deep wells gave nitrate concentrations in groundwater below the root zone. A sensitivity analysis of the program demonstrated how important nitrogen and water uptakes values were to the model predictions. An increase of 1% in nitrogen uptake or of 0.4% in crop coefficients generated 1% decrease in nitrogen concentration of the leachate. These results are important to consider when adopting highly uncertain literature values for crop uptakes -especially with poplars. The field validation of the model showed promising results in terms of estimating average yearly leachate concentrations in nitrogen resulting from land application of wastewater, but also suggested that more groundwater wells were needed to obtain a statistically significant validation of the model. These preliminary field results indicate that the model can provide an indication of groundwater nitrogen concentration trends but needs to further verified to be used confidently as a predictive tool. Close

• 8. [Article] Calibration of crop water use with the Penman equation under United Arab Emirates conditions

  Water shortage is one of the biggest problems facing agricultural development in the United Arab Emirates, because of the extremely arid climate and the large amount of irrigation water that is used for ...

  Citation × Citation Citation Abstract Copy Title: Calibration of crop water use with the Penman equation under United Arab Emirates conditions Author: Mohammed, Fareed H. A. N. Water shortage is one of the biggest problems facing agricultural development in the United Arab Emirates, because of the extremely arid climate and the large amount of irrigation water that is used for crops. Prediction of crop water requirements is essential to solve water management problems in this country. Two versions of the Penman equation, FAO and Wright, were used to estimate reference crop evapotranspiration from meteorological data for three regions in the U. A. E.; Northern, Central, and Eastern. Lysimeter measurements at the Northern region were provided for five crops; tomato for one season; cabbage, cucumber, and squash each for two seasons; and watermelon for three seasons. Crop evapotranspiration was estimated for these crops and related to measured crop evapotranspiration. It was found that there is great variation in measured crop evapotranspiration between seasons for individual crops, due to technical problems with the lysimeter. Combined seasons were used to calibrate the Penman equation, and the results indicated that the calibration improved the estimated crop evapotranspiration. Calibration coefficients for individual crops and for individual methods were calculated. Reference crop evapotranspiration (Etr) value for the three regions were correlated. A high correlation of estimated Etr among the three regions was found. Coefficients were developed to predict Etr at the Central and Eastern regions from the Etr at the Northern region. Title: Calibration of crop water use with the Penman equation under United Arab Emirates conditions Author: Mohammed, Fareed H. A. N. Water shortage is one of the biggest problems facing agricultural development in the United Arab Emirates, because of the extremely arid climate and the large amount of irrigation water that is used for crops. Prediction of crop water requirements is essential to solve water management problems in this country. Two versions of the Penman equation, FAO and Wright, were used to estimate reference crop evapotranspiration from meteorological data for three regions in the U. A. E.; Northern, Central, and Eastern. Lysimeter measurements at the Northern region were provided for five crops; tomato for one season; cabbage, cucumber, and squash each for two seasons; and watermelon for three seasons. Crop evapotranspiration was estimated for these crops and related to measured crop evapotranspiration. It was found that there is great variation in measured crop evapotranspiration between seasons for individual crops, due to technical problems with the lysimeter. Combined seasons were used to calibrate the Penman equation, and the results indicated that the calibration improved the estimated crop evapotranspiration. Calibration coefficients for individual crops and for individual methods were calculated. Reference crop evapotranspiration (Etr) value for the three regions were correlated. A high correlation of estimated Etr among the three regions was found. Coefficients were developed to predict Etr at the Central and Eastern regions from the Etr at the Northern region. Close

• 9. [Article] The effect of precipitation variation on soil moisture, soil nitrogen, nitrogen response and winter wheat yields in eastern Oregon

  The semi-arid regions of the Pacific Northwest are characterized by a high degree of annual temperature and precipitation variation. As a result of this climatic variation, dryland nitrogen fertilizer ...

  Citation × Citation Citation Abstract Copy Title: The effect of precipitation variation on soil moisture, soil nitrogen, nitrogen response and winter wheat yields in eastern Oregon Author: Glenn, D. M. (David Michael) The semi-arid regions of the Pacific Northwest are characterized by a high degree of annual temperature and precipitation variation. As a result of this climatic variation, dryland nitrogen fertilizer trials on fallow- ,wheat rotations typically demonstrate a variable response. Wheat growers in the area must not only cope with this climatic variation and its sundry effects upon their livelihood, they must also make decisions regarding the future level of anticipated climatic variation. The specific objectives were to: 1) develop a climatically responsive yield potential prediction model for soft white winter wheat from historical data at the Sherman Branch Experiment Station (Moro, OR); 2) modify this model for use on commercial fields; 3) field simulate five fallow-crop precipitation patterns characteristic of the variation found in the Sherman county area of eastern Oregon in order to test the yield potential model: 4) examine the effects of precipitation variation on nitrogen fertilizer responses, moisture storage and depletion and nitrogen mineralization; and 5) establish a quantitative relationship between precipitation/ soil moisture and nitrate accumulation in both the fallow and crop seasons. Two interacting regression models were developed to estimate grain yield levels in the 250-350 mm precipitation zone of eastern Oregon. The first model estimates yield potential from monthly precipitation and temperature values. The second model estimates the percent grain reduction due to delayed crop emergence. The grain yield model was adapted to commercial fields using a Productivity Index factor (PI). The PI is a measure of the productivity of other locations in relation to the Sherman Branch Experiment Station, using water-use-efficiency (WUE) as the basis of comparison. The field simulation of five fallow-crop precipitation patterns demonstrated that the maximum grain yield response occurred at 40 kg N (soil + fertilizer)/metric ton. The grain yield model demonstrated a 15% level of accuracy on a commercial field basis in both field trials and a survey of past production levels (1972-1980). It was hypothesized that the distribution of precipitation in the fallow and crop periods had an effect on both the amount and distribution of stored soil moisture. The field simulation demonstrated that more soil moisture was stored at the 90-240 cm depths by the patterns with more fallow season precipitation when measured in March of the crop year. Soil moisture storage and storage efficiencies fluctuated throughout the fallow and crop periods. At the cessation of the winter precipitation season in both the fallow and crop periods (March), the storage efficiency was highest when low levels of precipitation occurred. At this point in time, the mean crop period storage efficiency was 10% below the mean fallow period storage efficiency (34 and 44%, respectively) in both simulation studies. Soil moisture, temperature and immobilization requirements of crop residues interact to affect the net amount of nitrogen mineralization. The mineralization model proposed by Stanford and Smith (1972) was tested under field conditions. When the nitrogen immobilization requirement of the crop residues was included, the actual and predicted values were in agreement at the close of the 1978 fallow period. A nitrogen deficit was predicted at the 0-30 cm depth at the close of the 1980 fallow; however, the actual levels indicated a net accumulation of nitrate-nitrogen. Crop season mineralization, inferred from Mitscherlick and a-value extrapolations, in 1979 demonstrated that there was a decreasing amount of net mineralization during the crop season with increasing amounts of both fallow and crop season precipitation. Crop season mineralization in 1980 indicated that there was no net accumulation of nitrogen, rather a tie-up of 14 kg N/ha. This result reflects both the unsatisfied immobilization requirement predicted for the 1979 fallow season and crop season denitrification. Title: The effect of precipitation variation on soil moisture, soil nitrogen, nitrogen response and winter wheat yields in eastern Oregon Author: Glenn, D. M. (David Michael) The semi-arid regions of the Pacific Northwest are characterized by a high degree of annual temperature and precipitation variation. As a result of this climatic variation, dryland nitrogen fertilizer trials on fallow- ,wheat rotations typically demonstrate a variable response. Wheat growers in the area must not only cope with this climatic variation and its sundry effects upon their livelihood, they must also make decisions regarding the future level of anticipated climatic variation. The specific objectives were to: 1) develop a climatically responsive yield potential prediction model for soft white winter wheat from historical data at the Sherman Branch Experiment Station (Moro, OR); 2) modify this model for use on commercial fields; 3) field simulate five fallow-crop precipitation patterns characteristic of the variation found in the Sherman county area of eastern Oregon in order to test the yield potential model: 4) examine the effects of precipitation variation on nitrogen fertilizer responses, moisture storage and depletion and nitrogen mineralization; and 5) establish a quantitative relationship between precipitation/ soil moisture and nitrate accumulation in both the fallow and crop seasons. Two interacting regression models were developed to estimate grain yield levels in the 250-350 mm precipitation zone of eastern Oregon. The first model estimates yield potential from monthly precipitation and temperature values. The second model estimates the percent grain reduction due to delayed crop emergence. The grain yield model was adapted to commercial fields using a Productivity Index factor (PI). The PI is a measure of the productivity of other locations in relation to the Sherman Branch Experiment Station, using water-use-efficiency (WUE) as the basis of comparison. The field simulation of five fallow-crop precipitation patterns demonstrated that the maximum grain yield response occurred at 40 kg N (soil + fertilizer)/metric ton. The grain yield model demonstrated a 15% level of accuracy on a commercial field basis in both field trials and a survey of past production levels (1972-1980). It was hypothesized that the distribution of precipitation in the fallow and crop periods had an effect on both the amount and distribution of stored soil moisture. The field simulation demonstrated that more soil moisture was stored at the 90-240 cm depths by the patterns with more fallow season precipitation when measured in March of the crop year. Soil moisture storage and storage efficiencies fluctuated throughout the fallow and crop periods. At the cessation of the winter precipitation season in both the fallow and crop periods (March), the storage efficiency was highest when low levels of precipitation occurred. At this point in time, the mean crop period storage efficiency was 10% below the mean fallow period storage efficiency (34 and 44%, respectively) in both simulation studies. Soil moisture, temperature and immobilization requirements of crop residues interact to affect the net amount of nitrogen mineralization. The mineralization model proposed by Stanford and Smith (1972) was tested under field conditions. When the nitrogen immobilization requirement of the crop residues was included, the actual and predicted values were in agreement at the close of the 1978 fallow period. A nitrogen deficit was predicted at the 0-30 cm depth at the close of the 1980 fallow; however, the actual levels indicated a net accumulation of nitrate-nitrogen. Crop season mineralization, inferred from Mitscherlick and a-value extrapolations, in 1979 demonstrated that there was a decreasing amount of net mineralization during the crop season with increasing amounts of both fallow and crop season precipitation. Crop season mineralization in 1980 indicated that there was no net accumulation of nitrogen, rather a tie-up of 14 kg N/ha. This result reflects both the unsatisfied immobilization requirement predicted for the 1979 fallow season and crop season denitrification. Close

• 10. [Article] Lime Fertilizer Interactions Affecting Vegetable Crop Production

  p.109-119 from the 34th Annual Northwest Conference at Portland, Oregon. July 12-14, 1983.

  Citation × Citation Citation Abstract Copy Title: Lime Fertilizer Interactions Affecting Vegetable Crop Production Author: Hemphill, Delbert D., Jackson, T. L. (Thomas Lloyd), 1922- p.109-119 from the 34th Annual Northwest Conference at Portland, Oregon. July 12-14, 1983. Title: Lime Fertilizer Interactions Affecting Vegetable Crop Production Author: Hemphill, Delbert D., Jackson, T. L. (Thomas Lloyd), 1922- p.109-119 from the 34th Annual Northwest Conference at Portland, Oregon. July 12-14, 1983. Close