PT - JOURNAL ARTICLE AU - Scharf, P. C. AU - Schmidt, J. P. AU - Kitchen, N. R. AU - Sudduth, K. A. AU - Hong, S. Y. AU - Lory, J. A. AU - Davis, J. G. TI - Remote sensing for nitrogen management DP - 2002 Nov 01 TA - Journal of Soil and Water Conservation PG - 518--524 VI - 57 IP - 6 4099 - http://www.jswconline.org/content/57/6/518.short 4100 - http://www.jswconline.org/content/57/6/518.full AB - Nitrogen application often dramatically increases crop yields, but N needs vary spatially across fields and landscapes. Remote sensing collects spatially dense information that may contribute to, or provide feedback about, N management decisions. There is potential to accurately predict N fertilizer need at each point in the field. This would reduce surplus N in the crop production system without reducing crop yield, which would in turn reduce N losses to surface and ground waters. Soil spectral properties (color) are related to soil organic matter and soil moisture levels, factors that influence the N-supplying ability of the soil. Plant spectral properties reflect crop N status and soil N availability, and they can be useful for directing in-season variable-rate N applications. Plant color may also be useful for assessing the adequacy of crop nitrogen supply achieved with a given nitrogen management practice. We outline the current status of these approaches, offer examples, discuss several N management contexts in which these approaches might be used, and consider possible future directions for this technology.