Mapping in-season soil nitrogen variability assessed through remote sensing

摘要

conventional recommendations of N fertilizer are based on composited soil samples taken over the entire field. This may result in either underfertilization or overfertilization due to the neglected spatial variability in the field. This paper shows amethodology to estimate in-season soil N at various growth stages of irrigated corn. Soil N was estimated from plant N assessed through remote sensing. The nitrogen reflectance index (NRI) was employed to estimate plant N. Regression analysis between soil N and plant N showed good relationships at various growth stages. Geographic information system (GIS) mapping of measured and estimated soil N showed an agreement except in locations where hot spots were measured.