ARS | Publication request: PREDICTING SPRING WHEAT YIELD AND PROTEIN THROUGH SENSOR-BASED TECHNOLOGY

Submitted to: State University Ag Report
Publication Type: Experiment Station
Publication Acceptance Date: February 26, 2006
Publication Date: June 1, 2006
Citation: Osborne, S.L., Gelderman, R. 2006. Predicting spring wheat yield and protein through sensor-based technology. State University Ag Report available at http://plantsci.sdstate.edu/soiltest/data2005/Report%2005-28.pdf.

Interpretive Summary: Applications of in-season nitrogen for winter wheat based on variable rate technologies have been developed and are in use in the southern Great Plains. Field experiments were established in Brookings and Gettysburg, SD to evaluate the GreenSeeker Hand Held optical sensor (NTech Industries, Ukiah, CA) for measuring in-season N status on spring wheat. Five N rates were applied pre-plant as ammonium nitrate. Sensor readings and plant biomass samples were collected at two separate growth stages (six leaves and boot). The sensor measures reflectance in the red and near infrared regions of the electromagnetic spectrum and calculates the normalized difference vegetation index (NDVI). The ability of the sensor readings to predict grain yield and protein for each sampling date was determined. In general, grain yield and protein increased with increasing N rate. Sensor readings (NDVI) collected at at six leaves and boot showed a significant relationship with grain yield, with readings collected at the later growth stage having higher correlations compared to the early sampling date. Initial results suggest that existing sensor-based variable nitrogen technology developed for winter wheat could be utilized in the northern Great Plains for estimating in-season nitrogen need for spring wheat, but additional testing is necessary.

Technical Abstract: Applications of in-season nitrogen for winter wheat based on variable rate technologies have been developed and are in use in the southern Great Plains. Field experiments were established in Brookings and Gettysburg, SD to evaluate the GreenSeeker Hand Held optical sensor (NTech Industries, Ukiah, CA) for measuring in-season N status on spring wheat. Five N rates were applied pre-plant as ammonium nitrate. Sensor readings and plant biomass samples were collected at Feekes 6 and Feekes 10 growth stages. The sensor measures reflectance in the red and near infrared (NIR) regions of the electromagnetic spectrum and calculates the normalized difference vegetation index (NDVI). The ability of the sensor readings to predict grain yield and protein for each sampling date was determined. In general, grain yield and protein increased with increasing N rate. Sensor readings (NDVI) collected at Feekes 6 and Feekes 10 showed a significant relationship with grain yield, with readings collected at the later growth stage having higher correlations compared to the early sampling date. Initial results suggest that existing sensor-based variable nitrogen technology developed for winter wheat could be utilized in the northern Great Plains for estimating in-season N need for spring wheat, but additional testing is necessary.