Nitrogen Recalibration for Corn in North Dakota

The nitrogen (N) recommendations for corn in North Dakota (ND) need to be updated using actual field results from ND. Existing recommendations are based on Minnesota data, and older ND field calibration data. There have been many changes in cropping systems especially conservation tillage adoption, weed control, and corn hybrid genetics. Many of the newer hybrids are more resistant to water limiting conditions experienced in parts of ND. The study will consist of N response research experiments at a number (8 to 10) of sites depending on resources and locating suitable field research sites. This study will be conducted for two years to generate data for up to 20 site-years of research results.


03 Mar 2012

2011 Annual Interpretive Summary

This is the second year of the project designed to allow the research-based re-evaluation of the corn N recommendations in North Dakota. A total of 22 sites were planned in 2011. With the sites from 2010, there have been a total of 36 sites that can be evaluated. In addition, sensor readings using both a Greenseeker® (N-Tech) sensor and a Holland Scientific Crop Circle sensor were used when the corn was about 6 leaf and again about 2 weeks later over the top, and at the later season also below canopy height. These sensor readings were taken to try to develop a predictive measurement to guide growers in the need for added N at side-dress time. The site yield and N-rate evaluations were evaluated as a whole and partitioned based on regional and soil considerations.

The response of corn to N rate from the total of the two years was quite variable (R2 = 0.19). The no-till sites, a total of five in the 2 years, responded differently than conventional sites, and the 50 lb N/A long-term credit used in the spring wheat and durum recommendations also appears to be justified for corn. High clay sites required far more N for similar yields as the remaining eastern North Dakota sites. Based on a comparison of similar yields from the rest of eastern North Dakota, clay sites lost about 80 lb N/A in 2010 due probably to denitrification and more than 120 lb N/A in 2011. The well-tiled clay sites were less affected by N loss and responses to N near those of medium-textured soil sites in the east. Considering the amount of N lost in high clay soils in 2010 and 2011, and probably by growers in many springs, there is ample cause to begin recommending a planned side-dress N application in high clay soils. It is planned to conduct field sites for two more years, 2012 and 2013, and then summarize the experimental results and release updated N recommendations for the various regions in North Dakota. ND-16