Three Alternative Nitrogen Management Strategies for Cereal Grain Production Brian Arnall Brian Arnall Plant and Soil Sciences Department Oklahoma State University

Introduction Scrutiny of Nitrogen Application Environmental impact Rise in Fuel and Nitrogen cost Temporal Variability What Nature Provides Unpredictable Variables

Response Index

N-Rich Strip The Nitrogen Rich Strip: –What is it? –When and Where can it be used? Ease of application Drive by visibility

N-Rich Strip Yes or No

N-Rich Strip Sensor Based Nitrogen Rate Calculator Using Sensor Data and the Nitrogen Fertilizer Optimization Algorithm, N-Rates are prescribed for that field and its condition.

Aug 16, 2002Aug 28, 2002 November March June Planting date days from planting to sensing (GDD>0) YP 0 Nitrogen Fertilizer Optimization Algorithm 1. Establish preplant N Rich Strip(NRS) 4. Determine Response Index (RI) 2. NDVI (biomass) =NDVI NRS /NDVI Farmer 3. Predict potential yield 5. Predict potential grain yield need # of days from planting to (YP 0 ) with added N, YP N =(YP 0 *RI) sensing (INSEY = biomass prod./day) 6. Fertilizer Rec = (grain N uptake INSEY vs. Yld eqn. YP N – grain N uptake YP 0 /0.7) RI YP N May June August CORN WHEAT NDVI (sensing date)

Ramp Calibration Strip The Ramp Calibration Strip –16 N rates 0 – 195 lb N ac -1 (can be adjusted for other crops) Rate Interval 10 ft (adjustable) Truck or ATV mounted

Ramp Calibration Strip Walk it off 0 N 195 N

Ramp Calibration Strip Sensor Based

Strip Alternatives

VRT Variable Rate N Application Resolution –Wheat.4 m 2 –Corn By-Plant

VRT Equipment

Questions? For More Information