Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: September 30, 2003
Publication Date: November 3, 2003
Citation: Meisinger, J.J., Hatfield, J.L., Kasper, T.C. 2003. Opportunities for real-time management of nitrogen fertilizers [abstract]. American Society of Agronomy. Agronomy Abstracts 2003 CDROM A08-meisinger196914. Technical Abstract: Real-time nitrogen (N) stress sensors, combined with variable rate N applicators, offer a major opportunity for improving N use efficiencies in many crops. Traditional N management is based on field-scale N credits and debits that have relied on pre-season deep soil nitrate tests, general soil organic N mineralization rates, manure/legume N credits, and estimates of expected yields over the soil types within a field. These traditional approaches have been partially successful, but have not overcome the inherent variability in the field N cycle that is generated from spatial variability in soil N transformations, spatial variation in manure application and manure N transformations, and the temporal variability of soil N transformations from one season to another due to rainfall. Several within-season N management tools have been developed to manage seasonal variations and broad-scale spatial variation through a timely monitoring of the plant or soil, e.g. the leaf chlorophyll meter, various plant-N tissue tests, and the pre-sidedress soil nitrate test. These seasonal tools have been shown to improve N use efficiency but are generally labor intensive and costly to apply to large areas. The recent advances in crop N-stress sensing on a sub-meter scale offer the opportunity to assess and manage the large spatial and temporal variability that is inherent in the soil N cycle.