What is in this article?:
- Fine-tuning nitrogen applications is a good bet economically, environmentally
- Use of microbial inhibitors
- Tools to tame N-response variability
- Stretch input dollars by identifying Economic Optimum nitrogen Rates for your fields, their soils and your management system. Consider risk of monetary and environmental–loss risks.
- Delay some or most nitrogen applications to the V6 growth stage to increase utilization, reduce waste and adjust rates to take advantage of seasonal variability.
- Use technology to better analyze crop needs in-season, deliver nitrogen efficiently and evaluate utilization post season.
- Encourage, support and participate in university efforts and grower-sponsored research, such as Discovery Farms and On-Farm Networks, to explore efficient and effective nutrient management.
Tools to tame N-response variability
Purdue researchers recommend these management tools to calibrate nitrogen rates that are the most profitable and agronomically optimal:
- Apply nitrogen shortly before planting or in a sidedress program, closer to nitrogen uptake/
- The most effective application is to inject nitrogen before rapid crop uptake at the V6 stage.
- Use the pre-sidedress nitrate test to estimate soil nitrogen supply in manured fields or in high-organic-matter soils
- Use a chlorophyll meter or active sensor in conjunction with a high-N reference strip during the growing season to evaluate crop nitrogen status.
- Nitrification and urease inhibitors with early spring application, before planting or anytime it will be two months or more before the crop will use the N, are effective.
- An end-of-season stalk-nitrate test to determine if the "right" rate of nitrogen was applied for the season.
These tools, combined with current best management practices, can only improve nitrogen management. Important as that is in the short term economically, it may be even more important in the long term.