We designed this study to demonstrate differences in nitrogen rates and yields under different application times of the same nitrogen product, in an area where the producer planted corn for two consecutive growing seasons.
We conducted this trial to:
- demonstrate strip till application of anhydrous ammonia, a proven conservation practice
- demonstrate how the farmer can conduct his own on-farm NUE using field-scale equipment with minimal disruption of his normal field operations
- show how RTK guidance and variable-rate application equipment can improve nitrogen application efficiency
- show how RTK yield monitoring equipment works at harvest time
- show how the farmer and his advisers can collect data and make management decisions during the winter months.
The farmer applied anhydrous ammonia fertilizer in the fall, in a strip-tilled area. He harvested the plots with his yield-monitor-equipped combine.
We analyzed his yield data along with fertilizer rate and other data including field observations and soil and plant analysis.
We used the Crop Nutrient Response Tool* to determine the maximum economic rate of nitrogen, 212 pounds per acre.
Take Home Lessons
- Spring application afforded the highest yields
- Spring application revealed most efficient nitrogen use
- Fall application displayed lower economic return on nitrogen, due to nitrogen losses
- Fall timing had lowest yield
- Split timing was better than fall but not as good as spring application
*International Plant Nutrition Institute designed the Crop Nutrient Response Tool to assist interpretation and record-keeping for on-farm field crop trials involving multiple rates of any added nutrient. It provides the an estimate of optimum rate for a single-year response - the most economic rate (MERN) at which it is profitable to apply a purchased nutrient - from limited data. It can also estimate several basic forms of nutrient use efficiency (NUE): partial factor productivity, agronomic efficiency, partial nutrient balance, and recovery efficiency. Source: International Plant Nutrition Institute