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United States Department of Agriculture

Agricultural Research Service

Title: Evaluating Existing Sensor-Based Variable Nitrogen Technology for Spring Wheat Production in the Northern Great Plains

Authors
item Osborne, Shannon
item Raun, W - OKLAHOMA STATE UNIV

Submitted to: International Conference on Precision Agriculture Abstracts & Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 15, 2004
Publication Date: July 26, 2004
Citation: Osborne, S.L., Raun, W.R. 2004. Evaluating existing sensor-based variable nitrogen technology for spring wheat production in the northern Great Plains. In: D.J. Mulla (ed.), Proceedings of the 7th International Conference on Precision Agriculture. July 25-28, 2004, Minneapolis, Minnesota.

Interpretive Summary: Precision ag technologies for in-season application of nitrogen (N) to winter wheat have been developed, and are in use in the southern Great Plains (Oklahoma, Kansas and Texas). Concerns arise about the suitability of this technology for spring wheat production in the northern Great Plains (North Dakota, South Dakota and Minnesota). A field experiment was established in Brookings, SD to evaluate the GreenSeeker Hand Held optical sensor (NTech Industries, Ukiah, CA) for predicting in-season N status on three spring wheat cultivars ('Ingot', 'Oxen', and 'Walworth') across five N treatments. Nitrogen rates were 0, 30, 60, 90, and 120 lb/ac applied at pre-plant. Sensor readings and plant biomass samples were collected at two different growth stages (Feekes 6 and Feekes 10). The ability of the sensor readings to predict biomass, plant N concentration, and plant N uptake for each sampling date was determined. In general, biomass, plant N concentration, and N uptake increased with increasing N rate for both sampling dates. Readings collected at the different growth stages showed a significant relationship with plant biomass, N concentration and N uptake for all varieties. Plant N uptake and sensor readings resulted in a higher regression coefficients compared to biomass and plant N concentration for all varieties. 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.

Technical Abstract: Sensor-based technologies for in-season application of nitrogen (N) to winter wheat (Triticum aestivum L.) have been developed, and are in use in the southern Great Plains. Questions arise about the suitability of this technology for spring wheat production in the northern Great Plains. A field experiment was established in Brookings, SD to evaluate the GreenSeeker Hand Held optical sensor (NTech Industries, Ukiah, CA) for predicting in-season N status on three spring wheat cultivars ('Ingot', 'Oxen', and 'Walworth') across five N treatments. Nitrogen rates were 0, 34, 68, 102, and 136 kg N ha-1 applied at 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. A normalized difference vegetation index (NDVI) was calculated. The ability of the sensor readings to predict biomass, plant N concentration, and plant N uptake for each sampling date was determined. In general, biomass, plant N concentration, and N uptake increased with increasing N rate for both sampling dates. Readings collected at Feekes 6 and Feekes 10 showed a significant relationship with plant biomass, N concentration and N uptake for all varieties. Plant N uptake and NDVI resulted in a higher regression coefficients compared to biomass and plant N concentration for all varieties. 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.

Last Modified: 12/19/2014