Reference Strips and Sensors in Sorghum Brian Arnall

Reference Strips and Sensors in Sorghum Brian Arnall Oklahoma State University Dept Plant and Soil Sciences

Outline • Reference Strips • Yield Prediction Models • SBNRC

Reference Strips • Litmus Paper for the Field • • N-Rich N-Ramp Nutrient-Rich Lime Strip

The N RICH Strip

Long-Term Winter Wheat Grain Yields, Lahoma, OK Ave Yld 42 bu/ac

N-Rich Strip Will tell you: Yes, I need Nitrogen No, I do not Need any!

N-Rich Strip Mid-Season Evaluation of N Rich Strip (Ciudad Obregon, MX) Average Wheat Yields = 150 bu/ac (irrigated spring wheat) 300 lbs N ac-1 0 lbs N ac -1

Response Index Response < 1 = No Response to Fert N Ranges from 1 to 4

Response to Fertilizer N Long-Term Corn Experiment Mead, NE, 1969 -1983 Prof. R. A. Olson Gordon Johnson

Response Index 2004 variable from year to year in the same field 1995 Long term N-P-K Experiment (1969 -2008) Dr. Billy Tucker

Introduce a Lime Reference Strip used with or without an Nrich strip in acid soils to show the benefits of liming Nitrogen strip Lime Referenc e Strip

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

Handheld Unit – Records NDVI Can Help Estimate • Temporal Variability • In season environmental conditions

Yield Prediction SBNRC (YP 0*RI =YPN) 100 Pre (100 lbs N/ac applied preplant)

Thank You! • Corn and Sorghum Nutrient Need Pete’s Sheets