Nitrogen Recalibration for Corn in North Dakota
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Objective
- Develop a modern research database for confidently reviewing and revising the current nitrogen (N) recommendations for corn in North Dakota.
Study Description
| Locations: | 77 on-farm trials | |
| Replicates: | 4 per location | |
| Nitrogen Rates: | 0 lb N/acre | 40 lb N/acre |
| 80 lb N/acre | 120 lb N/acre | |
| 160 lb N/acre | 200 lb N/acre | |
Optical Sensor Measurements
- From 2011 through 2013, 60 trials were scanned with both the Trimble® Greenseeker® and Holland Scientific Crop Circle™ active optical sensors at V6 and V12.
Results
- Both active optical sensors readings were transformed into INSEY (in-season estimate of yield) by dividing the sensor reading by growing degree days (GDD) from planting date.
- Multiplying the sensor readings by corn height increased the relationship of INSEY and yield (Figure 1).
- The yield and N rate relationship was strengthened when preplant nitrate-N to 2-ft depth was included and a 40 lb/acre soybean credit where corn followed soybean.
- The yield to N rate relationships were stronger when the data were divided between west of Missouri River sites and east of Missouri River sites.
Figure 1. All eastern medium texture conventional sites (2011-2012) Crop Circle 5-6 Leaf NDVI INSEY X height vs. corn yield.
- The eastern site relationships were strongest when divided into long-term no-till sites and conventional sites.
- The eastern conventional site relationships were strongest when segregated into high-clay sites and medium texture sites (Figure 2).
Figure 2. Return to N with total known available N for east of Missouri River sites, assuming $0.40/lb N and $4/bu corn. *Long-term no-till N credit not included.
- A return-to-N economic production function will be used to recommend N rates for different corn prices and N costs.
- New corn N recommendations and algorithms using GreenSeeker and Crop Circle active-optical sensors will be available summer 2014.
Research conducted by Dave Franzen, North Dakota State University Extension Service, as a part of the Pioneer Crop Management Research Awards (CMRA) Program. This program provides funds for agronomic and precision farming studies by university and USDA cooperators throughout North America. The awards extend for up to 4 years and address crop management information needs of Pioneer agronomists, Pioneer sales professionals and customers.
2013 data are based on average of all comparisons made in 77 locations through October 31, 2013. Multi-year and multi-location is a better predictor of future performance. Do not use these or any other data from a limited number of trials as a significant factor in product selection. Product responses are variable and subject to a variety of environmental, disease, and pest pressures. Individual results may vary. All products are trademarks of their manufacturers.