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ARS Home » Plains Area » Brookings, South Dakota » Integrated Cropping Systems Research » Research » Publications at this Location » Publication #201119
Title: Utilizing the Greenseeker to Evaluate Spring Wheat Growth and Yield

Author
item Osborne, Shannon
item GELDERMAN, RON - SOUTH DAKOTA STATE UNIV
item WEINKAUF, ANN - SOUTH DAKOTA STATE UNIV

Submitted to: Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 10/2/2006
Publication Date: 11/7/2006
Citation: Osborne, S.L., Gelderman, R., Weinkauf, A.M. 2006. Utilizing the Greenseeker to Evaluate Spring Wheat Growth and Yield. 2006 North Central Extension-Industry Soil Fertility Conference, Des Moines, Iowa, November 7-8, 2006.

Interpretive Summary: There is currently little information on the use of existing sensor-based technologies for in-season application of nitrogen (N) to spring wheat (Triticum aestivum L.) in the northern Great Plains. Over the past decade researchers in the southern Great Plains have developed the Greenseeker as a tool for on-the-go N application to winter wheat. 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 nitrogen status on spring wheat. The ability of the sensor readings to measure biomass, plant nitrogen uptake, and predict grain yield and protein for each sampling date was determined. In general, in-season plant biomass, plant nitrogen concentration, and grain yield increased with increasing nitrogen rate. Sensor readings (NDVI) collected at six leaves and boot showed a significant relationship with plant biomass, nitrogen uptake and 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: There is currently little information on the use of existing sensor-based technologies for in-season application of nitrogen (N) to spring wheat (Triticum aestivum L.) in the northern Great Plains. Over the past decade researchers in the southern Great Plains have developed the Greenseeker as a tool for on-the-go N application to winter wheat. 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 measure biomass, plant N uptake, and predict grain yield and protein for each sampling date was determined. In general, in-season plant biomass, plant N concentration, and grain yield increased with increasing N rate. Sensor readings (NDVI) collected at Feekes 6 and Feekes 10 showed a significant relationship with plant biomass, N uptake and grain yield, with readings collected at the later growth stage having higher correlation 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.