- Agronomic: corn
- Animal Production: feed/forage
- Crop Production: nutrient management
- Education and Training: decision support system, extension, focus group, on-farm/ranch research, participatory research, technical assistance, workshop
- Soil Management: soil analysis
Problem and justification
Nitrogen recommendations from soil testing laboratories are based on results of nitrogen response trials where the average nitrogen rate across many trials have standard deviations often 40% of the mean. Most of the nitrogen response trials have been completed on soils with no manure history, which are less variable in their nitrogen mineralization capability than soils with a history of manure applications. Most farmers who grow corn and most agricultural service providers who advise farmers understand this problem of the inability of soil testing laboratories to provide accurate nitrogen recommendations for individual fields, especially for fields with manure histories. The result is farmers customize the generalized recommendations from soil test laboratories for their individual fields. The problem with farmers customizing nitrogen recommendations is that corn does not provide visual differences between optimal nitrogen and nitrogen excess nor are yields reduced when excess nitrogen is available to corn. Corn does, however, provide distinct visual symptoms of nitrogen deficiency. With only feedback about nitrogen deficiencies, farmers are unable to accurately customize nitrogen recommendations and are naturally inclined to apply excess nitrogen due to the way grasses express nitrogen status. The 500 dairy farmers in Connecticut, Massachusetts, and Maine plant a total of 57,522 acres of silage corn, which underpins their profitability. Improving nitrogen management will improve the profitability and environmental footprint of dairy farms.
Solution and approach
The solution has two parts. The first is the creation of customized nitrogen recommendations using results from Adapt-N (a recently verified model for predicting nitrogen needs of corn, late-season aerial images of fields, a new soil biological test that estimates nitrogen mineralization, and fall soil nitrate concentrations. The information from these diverse nitrogen management tools will provide farmers with choices of objective feedback about their nitrogen management. The second part of the solution is the planting of cover crops by September 15 to recover residual soil nitrate that may remain in the soil after silage corn harvest, and be subjected to leaching loss if not sequestered. The benefit of the new objective information provided to farmers about the nitrogen status of their corn fields will be more accurate manure and fertilizer nitrogen applications. The benefit from planting cover crops before September 15 will be reduced nitrate leaching and reduced nitrogen applications in the next season due to nitrogen recovered by the cover crop being available to the subsequent corn crop.
Performance targets from proposal:
27 dairy farmers improve nitrogen management on 1,500 acres of corn (100 fields) by increasing yield, reducing fertilizer rate, or reducing nitrogen losses from planting cover crops by September 15, resulting in a total annual savings of $54,000.