In-Season N Rate Decisions: Soil Nitrate Vs. Crop Color.

In-season N management for corn and other crops creates opportunities for improved N rate decisions relative to pre-plant applications.  Soil tests include N mineralized in-season, crop color can be used, weather to date can be integrated.  An experiment was initiated in 2007 comparing preplant N rates to 3 rate decision systems for in-season N:  pre-sidedress soil nitrate test, chlorophyll meter, and active reflectance sensor.  After 8 years, cumulative yield with in-season N management is more than 250 bushels/acre ahead of preplant N management for all 3 in-season decision systems.  Among the 3 in-season decision systems, N rate, yield, and profitability were all lower with the soil nitrate test than with the two decision systems based on crop color.