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• 11. [Image] Draft resource management plan/environmental impact statement for the Upper Klamath Basin

  	"March 1994."
  	Citation × Citation Citation Abstract Copy Title: Draft resource management plan/environmental impact statement for the Upper Klamath Basin Author: United States. Bureau of Land Management. Klamath Falls Resource Area Office Year: 1994, 2005 "March 1994." Title: Draft resource management plan/environmental impact statement for the Upper Klamath Basin Author: United States. Bureau of Land Management. Klamath Falls Resource Area Office Year: 1994, 2005 "March 1994." Close

• 12. [Image] Water allocation in the Klamath Reclamation Project, 2001 : an assessment of natural resource, economic, social, and institutional issues with a focus on the Upper Klamath Basin

  	"Reprinted May 2003."; Includes bibliographical references; Also available at http://eesc.oregonstate.edu/agcomwebfile/edmat/html/sr/sr1037/sr1037.html
  	Citation × Citation Citation Abstract Copy Title: Water allocation in the Klamath Reclamation Project, 2001 : an assessment of natural resource, economic, social, and institutional issues with a focus on the Upper Klamath Basin Author: Braunworth, William S. Year: 2003, 2004 "Reprinted May 2003."; Includes bibliographical references; Also available at http://eesc.oregonstate.edu/agcomwebfile/edmat/html/sr/sr1037/sr1037.html Title: Water allocation in the Klamath Reclamation Project, 2001 : an assessment of natural resource, economic, social, and institutional issues with a focus on the Upper Klamath Basin Author: Braunworth, William S. Year: 2003, 2004 "Reprinted May 2003."; Includes bibliographical references; Also available at http://eesc.oregonstate.edu/agcomwebfile/edmat/html/sr/sr1037/sr1037.html Close

• 13. [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

• 14. [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

• 15. [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

• 16. [Article] Air-quality and Climatic Consequences of Bioenergy Crop Cultivation

  Bioenergy is expected to play an increasingly significant role in the global energy budget. In addition to the use of liquid energy forms such as ethanol and biodiesel, electricity generation using processed ...

  Citation × Citation Citation Abstract Copy Title: Air-quality and Climatic Consequences of Bioenergy Crop Cultivation Author: Porter, William Christian Year: 2013 Bioenergy is expected to play an increasingly significant role in the global energy budget. In addition to the use of liquid energy forms such as ethanol and biodiesel, electricity generation using processed energy crops as a partial or full coal alternative is expected to increase, requiring large-scale conversions of land for the cultivation of bioenergy feedstocks such as cane, grasses, or short rotation coppice. With land-use change identified as a major contributor to changes in the emission of biogenic volatile organic compounds (BVOCs), many of which are known contributors to the pollutants ozone (O3) and fine particulate matter (PM2.5), careful review of crop emission profiles and local atmospheric chemistry will be necessary to mitigate any unintended air-quality consequences. In this work, the atmospheric consequences of bioenergy crop replacement are examined using both the high-resolution regional chemical transport model WRF/Chem (Weather Research and Forecasting with Chemistry) and the global climate model CESM (Community Earth System Model). Regional sensitivities to several representative crop types are analyzed, and the impacts of each crop on air quality and climate are compared. Overall, the high emitting crops (eucalyptus and giant reed) were found to produce climate and human health costs totaling up to 40% of the value of CO2 emissions prevented, while the related costs of the lowest-emitting crop (switchgrass) were negligible. Title: Air-quality and Climatic Consequences of Bioenergy Crop Cultivation Author: Porter, William Christian Year: 2013 Bioenergy is expected to play an increasingly significant role in the global energy budget. In addition to the use of liquid energy forms such as ethanol and biodiesel, electricity generation using processed energy crops as a partial or full coal alternative is expected to increase, requiring large-scale conversions of land for the cultivation of bioenergy feedstocks such as cane, grasses, or short rotation coppice. With land-use change identified as a major contributor to changes in the emission of biogenic volatile organic compounds (BVOCs), many of which are known contributors to the pollutants ozone (O3) and fine particulate matter (PM2.5), careful review of crop emission profiles and local atmospheric chemistry will be necessary to mitigate any unintended air-quality consequences. In this work, the atmospheric consequences of bioenergy crop replacement are examined using both the high-resolution regional chemical transport model WRF/Chem (Weather Research and Forecasting with Chemistry) and the global climate model CESM (Community Earth System Model). Regional sensitivities to several representative crop types are analyzed, and the impacts of each crop on air quality and climate are compared. Overall, the high emitting crops (eucalyptus and giant reed) were found to produce climate and human health costs totaling up to 40% of the value of CO2 emissions prevented, while the related costs of the lowest-emitting crop (switchgrass) were negligible. Close

• 17. [Article] Reducing the Negative Human-Health Impacts of Bioenergy Crop Emissions through Region-Specific Crop Selection

  An expected global increase in bioenergy-crop cultivation as an alternative to fossil fuels will have consequences on both global climate and local air quality through changes in biogenic emissions of ...

  Citation × Citation Citation Abstract Copy Title: Reducing the Negative Human-Health Impacts of Bioenergy Crop Emissions through Region-Specific Crop Selection Author: Porter, William Christian, Rosenstiel, Todd N., Guenther, Alex, Lamarque, Jean-Francois, Barsanti, Kelley Year: 2015 An expected global increase in bioenergy-crop cultivation as an alternative to fossil fuels will have consequences on both global climate and local air quality through changes in biogenic emissions of volatile organic compounds (VOCs). While greenhouse gas emissions may be reduced through the substitution of next-generation bioenergy crops such as eucalyptus, giant reed, and switchgrass for fossil fuels, the choice of species has important ramifications for human health, potentially reducing the benefits of conversion due to increases in ozone (O3) and fine particulate matter (PM2.5) levels as a result of large changes in biogenic emissions. Using the Community Earth System Model we simulate the conversion of marginal and underutilized croplands worldwide to bioenergy crops under varying future anthropogenic emissions scenarios. A conservative global replacement using high VOCemitting crop profiles leads to modeled population-weighted O3 increases of 5–27 ppb in India, 1–9 ppb in China, and 1–6 ppb in the United States, with peak PM2.5 increases of up to 2 μg m−3 . We present a metric for the regional evaluation of candidate bioenergy crops, as well as results for the application of this metric to four representative emissions profiles using four replacement scales (10–100% maximum estimated available land). Finally, we assess the total health and climate impacts of biogenic emissions, finding that the negative consequences of using high-emitting crops could exceed 50% of the positive benefits of reduced fossil fuel emissions in value. Title: Reducing the Negative Human-Health Impacts of Bioenergy Crop Emissions through Region-Specific Crop Selection Author: Porter, William Christian, Rosenstiel, Todd N., Guenther, Alex, Lamarque, Jean-Francois, Barsanti, Kelley Year: 2015 An expected global increase in bioenergy-crop cultivation as an alternative to fossil fuels will have consequences on both global climate and local air quality through changes in biogenic emissions of volatile organic compounds (VOCs). While greenhouse gas emissions may be reduced through the substitution of next-generation bioenergy crops such as eucalyptus, giant reed, and switchgrass for fossil fuels, the choice of species has important ramifications for human health, potentially reducing the benefits of conversion due to increases in ozone (O3) and fine particulate matter (PM2.5) levels as a result of large changes in biogenic emissions. Using the Community Earth System Model we simulate the conversion of marginal and underutilized croplands worldwide to bioenergy crops under varying future anthropogenic emissions scenarios. A conservative global replacement using high VOCemitting crop profiles leads to modeled population-weighted O3 increases of 5–27 ppb in India, 1–9 ppb in China, and 1–6 ppb in the United States, with peak PM2.5 increases of up to 2 μg m−3 . We present a metric for the regional evaluation of candidate bioenergy crops, as well as results for the application of this metric to four representative emissions profiles using four replacement scales (10–100% maximum estimated available land). Finally, we assess the total health and climate impacts of biogenic emissions, finding that the negative consequences of using high-emitting crops could exceed 50% of the positive benefits of reduced fossil fuel emissions in value. Close

• 18. [Article] Impacts of crop level and vine vigor on vine balance and fruit composition in Oregon Pinot noir

  Vineyard management strategies, including vineyard floor management and crop level management, can be used to influence vine vigor and fruit composition. Two studies were conducted to evaluate the impact ...

  Citation × Citation Citation Abstract Copy Title: Impacts of crop level and vine vigor on vine balance and fruit composition in Oregon Pinot noir Author: Vance, Amanda J. Vineyard management strategies, including vineyard floor management and crop level management, can be used to influence vine vigor and fruit composition. Two studies were conducted to evaluate the impact of these practices on Pinot Noir in Oregon's Willamette Valley. Managing crop levels is common in cool climate vineyard production though it is a costly practice. With economic pressures, the premium winegrape industry is questioning whether they can reduce production costs and increase yields without compromising quality. A crop thinning trial was conducted in 2010 and 2011 to address these concerns and to better understand the role of vine balance on fruit composition. Crop levels were moderately (35% crop removed) or severely (65% crop removed) thinned at pre-bloom, fruit set, lag phase, or véraison and compared to full crop treatments. In both years, crop thinning reduced yields but had no effect on berry weight or cluster size. In 2010, poor fruit set reduced overall yields, and thinning treatments resulted in very few differences in vine growth, cluster architecture or fruit composition, including total soluble solids (TSS), pH, titratable acidity (TA), yeast assimilable nitrogen (YAN), anthocyanins, phenolics and tannins. In 2011, yields were much higher due to high fruit set and larger cluster size. No differences were found in vine growth (leaf areas or pruning weights) or fruit YAN, but thinned vines had higher TSS and pH and lower TA than full crop vines at harvest. Fruit thinned at lag phase and véraison had higher TSS and lower TA than fruit thinned pre-bloom. Intensity of thinning had a stronger influence on anthocyanin and tannin concentration than timing, while phenolics were not impacted by either factor. Ravaz index values (fruit yield/pruning weight) below 2.25 and leaf area to yield ratios of 2.25 to 3.25 m²/kg improved fruit composition in 2011 as did later season thinning, though data from the remaining years of this study will provide more insight into appropriate crop load metrics for cool climate Pinot Noir. A second study was implemented in 2011 to determine the impact of crop thinning in vines with different levels of vegetative vigor caused by three vineyard floor management techniques: permanent grass (Festuca rubra spp. rubra) cover (grass), alternating grass cover and tillage (grass & tilled), and tillage of every alleyway (tilled). Crop was thinned at the BB stage of berry development (EL stage 73) to one cluster per shoot (half crop) or not thinned (full crop); all cluster wings were removed at the time of thinning. Tillage treatments had been in place four years prior to the start of the study and competition for nitrogen in grass caused reduced early season vine growth, leaf chlorophyll and canopy size at both bloom and véraison while crop thinning increased canopy size at véraison. Yields were altered by tillage and crop thinning treatments, as grass had fewer clusters per shoot and berries per cluster, and crop thinning reduced yields to 64.7% of full crop across all tillage treatments. At harvest, grass had the lowest TA while TSS and pH were not affected by tillage. Crop thinning increased TSS but did not impact pH or TA. Anthocyanins were affected by both tillage and thinning and were found to be related to vine yield, YAN, leaf N, and leaf area index. Tannins were highest in grass but were not affected by crop thinning, and phenolics were not changed by either factor. Few interactions between tillage and crop thinning were found, but as variables such as yield per vine were impacted by both treatment factors, monitoring long term effects of crop Title: Impacts of crop level and vine vigor on vine balance and fruit composition in Oregon Pinot noir Author: Vance, Amanda J. Vineyard management strategies, including vineyard floor management and crop level management, can be used to influence vine vigor and fruit composition. Two studies were conducted to evaluate the impact of these practices on Pinot Noir in Oregon's Willamette Valley. Managing crop levels is common in cool climate vineyard production though it is a costly practice. With economic pressures, the premium winegrape industry is questioning whether they can reduce production costs and increase yields without compromising quality. A crop thinning trial was conducted in 2010 and 2011 to address these concerns and to better understand the role of vine balance on fruit composition. Crop levels were moderately (35% crop removed) or severely (65% crop removed) thinned at pre-bloom, fruit set, lag phase, or véraison and compared to full crop treatments. In both years, crop thinning reduced yields but had no effect on berry weight or cluster size. In 2010, poor fruit set reduced overall yields, and thinning treatments resulted in very few differences in vine growth, cluster architecture or fruit composition, including total soluble solids (TSS), pH, titratable acidity (TA), yeast assimilable nitrogen (YAN), anthocyanins, phenolics and tannins. In 2011, yields were much higher due to high fruit set and larger cluster size. No differences were found in vine growth (leaf areas or pruning weights) or fruit YAN, but thinned vines had higher TSS and pH and lower TA than full crop vines at harvest. Fruit thinned at lag phase and véraison had higher TSS and lower TA than fruit thinned pre-bloom. Intensity of thinning had a stronger influence on anthocyanin and tannin concentration than timing, while phenolics were not impacted by either factor. Ravaz index values (fruit yield/pruning weight) below 2.25 and leaf area to yield ratios of 2.25 to 3.25 m²/kg improved fruit composition in 2011 as did later season thinning, though data from the remaining years of this study will provide more insight into appropriate crop load metrics for cool climate Pinot Noir. A second study was implemented in 2011 to determine the impact of crop thinning in vines with different levels of vegetative vigor caused by three vineyard floor management techniques: permanent grass (Festuca rubra spp. rubra) cover (grass), alternating grass cover and tillage (grass & tilled), and tillage of every alleyway (tilled). Crop was thinned at the BB stage of berry development (EL stage 73) to one cluster per shoot (half crop) or not thinned (full crop); all cluster wings were removed at the time of thinning. Tillage treatments had been in place four years prior to the start of the study and competition for nitrogen in grass caused reduced early season vine growth, leaf chlorophyll and canopy size at both bloom and véraison while crop thinning increased canopy size at véraison. Yields were altered by tillage and crop thinning treatments, as grass had fewer clusters per shoot and berries per cluster, and crop thinning reduced yields to 64.7% of full crop across all tillage treatments. At harvest, grass had the lowest TA while TSS and pH were not affected by tillage. Crop thinning increased TSS but did not impact pH or TA. Anthocyanins were affected by both tillage and thinning and were found to be related to vine yield, YAN, leaf N, and leaf area index. Tannins were highest in grass but were not affected by crop thinning, and phenolics were not changed by either factor. Few interactions between tillage and crop thinning were found, but as variables such as yield per vine were impacted by both treatment factors, monitoring long term effects of crop Close

• 19. [Article] Cover crop effects on root rot of sweet corn and soil properties

  Root rot of sweet corn in western Oregon and Washington is a significant disease that can reduce yield of intolerant cultivars of processed sweet corn by fifty percent. Root rot is caused by a complex ...

  Citation × Citation Citation Abstract Copy Title: Cover crop effects on root rot of sweet corn and soil properties Author: Miyazoe, Mikio Root rot of sweet corn in western Oregon and Washington is a significant disease that can reduce yield of intolerant cultivars of processed sweet corn by fifty percent. Root rot is caused by a complex of soilborne organisms, including Drechslera sp., Phoma terrestris, and Pythium arrhenomanes. Processors have adopted tolerant cultivars but farmers continue to seek cultural management strategies that reduce inoculum potential. High rate manure and compost amendments (16.8 - 56.0 Mg ha⁻¹) suppress root rot of corn through general suppression but this practice is not agronomically viable. General suppression is typically associated with high rates of organic amendment and high microbial (FDA) activity. Processed vegetable farmers currently grow winter cover crops to improve soil and water quality and are interested in identifying cover crops that suppress root rot of corn and increase yield. High biomass cover crops can yield up to 12 Mg ha⁻¹ dry matter; this rate of organic amendment may or may not be sufficient to generate general suppression. However, specific cover crops, such as species and cultivars of crucifers and oats, have been shown to more suppressive than other cover crop species and cultivars against specific soilborne diseases. Oat is grown as a winter cover crop in the Willamette Valley and contains avenecin, a chemical that has been shown to have activity against pathogen propagules. In addition, in previous work in containers oat cover crops suppressed root rot of sweet corn. However, there is a concern that oat cover crops immobilize N and reduce corn yield. The objectives of this research were to 1) identify high biomass cover crops with agronomic potential for western Oregon processed vegetable cropping systems, 2) evaluate the impact of high biomass cover crops on root rot severity and yield of sweet corn, 3) determine whether there is a correlation between dry matter, soil microbial activity and root rot severity and 4) determine whether cover crops immobilize nitrogen and reduce corn yield. Research station field trials were conducted in 2003-04, 2004-05 and 2005-06 at the Oregon State University vegetable research farm in Corvallis, Oregon and an on-farm experiment was conducted in 2004-05 at Kenagy Family Farm in Albany, Oregon. Oat 'Saia' winter-killed in 2005-06 and mustard mix 'Caliente' winter-killed every winter except 2004-05, when winter temperatures never dropped below -7 °C. Rape 'Dwarf Essex', mustard 'Braco', and arugula are reliably winter-hardy. All mustard cover crop species are susceptible to white mold caused by Sclerotinia sclerotiorum, causal agent of white mold of snap bean. Oat (Avena sativa) is susceptible to barley yellow dwarf virus (BYDV), an important pathogen of grass seed crops. Mustard cover crops could contaminate cruciferous seed crops. All of the cover crop species evaluated demonstrated some potential to suppress root rot of corn. Oat 'Saia' was the most consistently suppressive; it suppressed root rot in 4 of 6 experiments. Sudangrass was suppressive in the only year it was evaluated as well as in container experiments in previous work. In general, cover crops increased or had no impact on shoot and root dry matter in greenhouse bioassays. There was only one significant cover crop treatment effect on yield; in 2006, the oat treatment increased yield by 11.6% compared to the fallow. Overall, cover crop aboveground dry matter (DM) ranged from 4.2 Mg ha⁻¹ (summer R 2003) to 12.2 Mg ha⁻¹ (winter O 2004). Overall, there was a significant relationship between cover crop DM and radicle rot severity in greenhouse bioassay but not in field experiment. Cover crop treatments consistently increased soil microbial activity. Overall, there was a significant negative correlation between microbial activity and root rot severity in greenhouse bioassays early after cover crop incorporation, but the correlation weakened over time and ultimately was lost by about 80 days after incorporation. The C:N of oat and rape residues was 51 and 21, respectively. Soil nitrogen was immobilized by both the oat and rape cover crops, but oat immobilized more N than rape. Corn grown in the oat treatment soils had lower SPAD values, but it is not clear whether foliar N was sufficiently low to reduce yield potential. There was no consistent trend in above- or below-ground corn dry matter after oat incorporation over the three years. In 2006, the oat treatment had no significant effect on corn DM but increased yield by 11.1%. More work is required to better understand the impact of oat cover crop N immobilization on corn N status and yield. Oat 'Saia' has the potential to suppress root rot of sweet corn and maintain or increase corn productivity. However, this oat cultivar is not reliably winter-hardy and is susceptible to BYDV. Future research should screen Avena species and/or cultivars for improved winter hardiness, BYDV resistance, and root rot suppressive potential. Title: Cover crop effects on root rot of sweet corn and soil properties Author: Miyazoe, Mikio Root rot of sweet corn in western Oregon and Washington is a significant disease that can reduce yield of intolerant cultivars of processed sweet corn by fifty percent. Root rot is caused by a complex of soilborne organisms, including Drechslera sp., Phoma terrestris, and Pythium arrhenomanes. Processors have adopted tolerant cultivars but farmers continue to seek cultural management strategies that reduce inoculum potential. High rate manure and compost amendments (16.8 - 56.0 Mg ha⁻¹) suppress root rot of corn through general suppression but this practice is not agronomically viable. General suppression is typically associated with high rates of organic amendment and high microbial (FDA) activity. Processed vegetable farmers currently grow winter cover crops to improve soil and water quality and are interested in identifying cover crops that suppress root rot of corn and increase yield. High biomass cover crops can yield up to 12 Mg ha⁻¹ dry matter; this rate of organic amendment may or may not be sufficient to generate general suppression. However, specific cover crops, such as species and cultivars of crucifers and oats, have been shown to more suppressive than other cover crop species and cultivars against specific soilborne diseases. Oat is grown as a winter cover crop in the Willamette Valley and contains avenecin, a chemical that has been shown to have activity against pathogen propagules. In addition, in previous work in containers oat cover crops suppressed root rot of sweet corn. However, there is a concern that oat cover crops immobilize N and reduce corn yield. The objectives of this research were to 1) identify high biomass cover crops with agronomic potential for western Oregon processed vegetable cropping systems, 2) evaluate the impact of high biomass cover crops on root rot severity and yield of sweet corn, 3) determine whether there is a correlation between dry matter, soil microbial activity and root rot severity and 4) determine whether cover crops immobilize nitrogen and reduce corn yield. Research station field trials were conducted in 2003-04, 2004-05 and 2005-06 at the Oregon State University vegetable research farm in Corvallis, Oregon and an on-farm experiment was conducted in 2004-05 at Kenagy Family Farm in Albany, Oregon. Oat 'Saia' winter-killed in 2005-06 and mustard mix 'Caliente' winter-killed every winter except 2004-05, when winter temperatures never dropped below -7 °C. Rape 'Dwarf Essex', mustard 'Braco', and arugula are reliably winter-hardy. All mustard cover crop species are susceptible to white mold caused by Sclerotinia sclerotiorum, causal agent of white mold of snap bean. Oat (Avena sativa) is susceptible to barley yellow dwarf virus (BYDV), an important pathogen of grass seed crops. Mustard cover crops could contaminate cruciferous seed crops. All of the cover crop species evaluated demonstrated some potential to suppress root rot of corn. Oat 'Saia' was the most consistently suppressive; it suppressed root rot in 4 of 6 experiments. Sudangrass was suppressive in the only year it was evaluated as well as in container experiments in previous work. In general, cover crops increased or had no impact on shoot and root dry matter in greenhouse bioassays. There was only one significant cover crop treatment effect on yield; in 2006, the oat treatment increased yield by 11.6% compared to the fallow. Overall, cover crop aboveground dry matter (DM) ranged from 4.2 Mg ha⁻¹ (summer R 2003) to 12.2 Mg ha⁻¹ (winter O 2004). Overall, there was a significant relationship between cover crop DM and radicle rot severity in greenhouse bioassay but not in field experiment. Cover crop treatments consistently increased soil microbial activity. Overall, there was a significant negative correlation between microbial activity and root rot severity in greenhouse bioassays early after cover crop incorporation, but the correlation weakened over time and ultimately was lost by about 80 days after incorporation. The C:N of oat and rape residues was 51 and 21, respectively. Soil nitrogen was immobilized by both the oat and rape cover crops, but oat immobilized more N than rape. Corn grown in the oat treatment soils had lower SPAD values, but it is not clear whether foliar N was sufficiently low to reduce yield potential. There was no consistent trend in above- or below-ground corn dry matter after oat incorporation over the three years. In 2006, the oat treatment had no significant effect on corn DM but increased yield by 11.1%. More work is required to better understand the impact of oat cover crop N immobilization on corn N status and yield. Oat 'Saia' has the potential to suppress root rot of sweet corn and maintain or increase corn productivity. However, this oat cultivar is not reliably winter-hardy and is susceptible to BYDV. Future research should screen Avena species and/or cultivars for improved winter hardiness, BYDV resistance, and root rot suppressive potential. Close

• 20. [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