65-5 Farm Nutrient Management through GreenSeeker ® (Remote Sensing) and Geographic Information System Technology

Poster Number 5

See more from this Division: Joint Sessions
See more from this Session: Digital Detection, Interpretation, and Mapping of Soil, Sediments and Bedrock (Posters)

Tuesday, 7 October 2008
George R. Brown Convention Center, Exhibit Hall E

Lizandra Nieves-Rivera, Colonial SWCD, Smithfield, VA, Wade Thomason, Corn and Small grain management, Virginia Polytechnic Institute and State University, Blacksburg, VA and Paul Davis, New Kent County, Virginia Cooperative Extension Service, Providence Forge, VA
Abstract:
Nitrogen (N) stimulates root growth, plant development and encourages the uptake of other nutrients. The crop may not efficiently use N when it is over applied. Excess N can leach from the root zone, causing water quality degradation.

The GreenSeeker® (NTech Ind.) is a real time, on-the-go remote sensing system that estimates crop N requirement based on the crop's vegetative index measured as NDVI (normalized difference vegetation index). NDVI is the ratio between the % of reflected red visible light and % of reflected near infrared light in the plant. The higher the absorption of visible red light compared to the reflected Near infrared light the healthier the plant.

Within a field, N use efficiency (NUE) can increase by closely matching fertilizer supply with crop demand.

Since 2000, research studies have been conducted to determine an algorithm that establishes the optimum N rate (Urea Ammonium Nitrate-UAN) for wheat at growth stage 30 in the mid-Atlantic region. The algorithm predicts plant N needs and potential response (Response Index) to fertilizer.

From 2005 - 2007 the GreenSeeker® system with the VA algorithm was compared to the Standard VA recommendation system based on crop tissue N concentration at GS-30. Across six locations, managing wheat using the Standard VA recommendation system yielded 88 bushels per acre, while the GreenSeeker applied significantly less N (about 15 %) and yielded 87 bushels per acre.

Following GIS analysis across two fields studied in 2005, N rate applications were similar in one field but 65 % less in a second field; the differences were due to the response index factor.

Overlaying soil series with the GreenSeeker shapefile helps explain field variability, highlights areas that require further attention for improvement and provides a precise nutrient application map for diagnostic use.

See more from this Division: Joint Sessions
See more from this Session: Digital Detection, Interpretation, and Mapping of Soil, Sediments and Bedrock (Posters)