Organic vegetable growers rely on legume cover crops as an economical source of plant-available N. This research evaluated N contributions to summer vegetable crops by cover crops (CC) residues by monitoring soil nitrate (NO3-N) concentrations during the summer crop growing season. Replicated field plots were established with three CC mixes:...
Organic vegetable growers rely on legume cover crops as an economical source of plant-available N. This research evaluated N contributions to summer vegetable crops by cover crops (CC) residues by monitoring soil nitrate (NO3-N) concentrations during the summer crop growing season. Replicated field plots were established with three CC mixes:...
Nitrogen can be lost when the quantity of available nitrogen exceeds crop demand or nitrogen availability is not in synchrony with crop demand. Either situation results in accumulation of available nitrogen, primarily in the nitrate form, at the end of the growing season. Over-winter nitrogen loss occurs primarily as nitrate-...
Specialty organic fertilizers used in organic vegetable production are expensive. So, from environmental and economic perspectives, growers want to maximize nitrogen (N) fertilizer use efficiency by the crop. This research was conducted to (1) determine sufficient N fertilizer rates for organic broccoli, (2) evaluate the efficacy of a specialty organic...
Specialty organic fertilizers used in organic vegetable production are expensive. So, from environmental and economic perspectives, growers want to maximize nitrogen (N) fertilizer use efficiency by the crop. This research was conducted to (1) determine sufficient N fertilizer rates for organic broccoli, (2) evaluate the efficacy of a specialty organic...
Following the surface application of urea to soil, there is the potential for nitrogen (N) loss from ammonia (NH3) volatilization until sufficient rain or irrigation has moved it into the soil. Many studies measuring NH3 loss have used laboratory and microplot field studies. The limitation of these techniques is that...
Following the surface application of urea to soil, there is the potential for nitrogen (N) loss from ammonia (NH3) volatilization until sufficient rain or irrigation has moved it into the soil. Many studies measuring NH3 loss have used laboratory and microplot field studies. The limitation of these techniques is that...
Predicting agronomic rates is important to derive optimum economic and environmental benefits from biosolids fertilizer applications. We conducted this research to 1) evaluate dryland wheat response to biosolids applications over a range of climate zones in the Pacific Northwest and 2) compare agronomic application rates predicted from yield curves with...
Computer simulation models provide insight into ammonia loss processes and the sensitivity of ammonia loss predictions to environmental and management variables.
As an example of how a simple computer simulation model can inform the Extension guideline development process, the ALFAM (Ammonia Volatilization from Field-Applied Animal Slurry) model was used to...
Credits for available N from past manure applications are often used in nutrient management planning. However, it is difficult to verify the accuracy of these credits. The major objective of this study was to estimate long-term effects of manure application on soil N mineralization. Specific objectives were to: 1) estimate...