N-STaR: Nitrogen-Soil Test for Agronomic Recommendations-for rice produced on silt loam soils


For field crops within the United States there is currently no analytical method used on a state or regional basis that can consistently and accurately predict the amount of soil nitrogen mineralized during a cropping season and in turn the nitrogen fertilizer needs required to achieve optimum yields on a site-specific or year to year basis. Current nitrogen fertilizer recommendations for rice, wheat, corn, grain sorghum and cotton in the U.S. are typically based on soil texture, variety, yield goal and/or the previous crop grown. This approach often will maximize yields, but in many cases leads to over-fertilization with nitrogen resulting in increased lodging potential as well as requiring additional input costs in the form of fungicides to reduce disease pressure. The soil test and calibration curve that has been developed will allow for site or field specific nitrogen fertilizer recommendations for these crops. In addition to the advantages listed above there is the potential for lower disease incidence and severity as well as lodging, which are secondary effects of proper nitrogen fertilizer management which can significantly influence yield and producer profitability.


This spectrofluorometric method/procedure for determining potentially mineralizable soil nitrogen is ideal for routine soil testing services and much faster than previously proposed methods which were labor intensive. Through automation, this procedure will be much more lucrative and allow adoption of this technology to a variety of public and private soil testing labs. The nitrogen quantified using this procedure has been calibrated to predict the site-specific nitrogen fertilizer needs for rice and wheat on silt loam soils and is currently being adapted for rice grown on clay soils and other crops grown on silt loam and clay soils. 


Currently, there is no technology like this in the world which can predict on a site-specific basis the exact nitrogen fertilizer rates required to achieve desired relative grain yields in any crop. Also the inclusion of three calibration curves which allow the producer to customize the recommendation based on their production philosophy is a new approach that has not been previously used. The technology presented here will revolutionize the agricultural industry in the United States and potentially the world.


Patent Information:
App Type Country Serial No. Patent No. File Date Issued Date Expire Date
Non-Provisional United States 14/209,249 9,354,235 3/13/2014 5/31/2016 6/19/2033
For Information, Contact:
Bryan Renk
Associate Director for Technology Commercialization
University of Arkansas TCO
Trenton Roberts
Richard Norman
Nathan Slaton
Charles Wilson
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