Comparison of Satellite Remote Sensing and Aerial Photography for Ability to Detect In-Season Nitrogen Stress in Corn

Abstract

Corn nitrogen stress is frequently associated with leaf chlorophyll content, which can be characterized by spectral reflectance measurements. Therefore, remote sensing using satellites and aerial platforms have great potential for characterizing corn nitrogen deficiency on a whole field scale. In this study, SPOT satellite images and digital aerial images were acquired on two commercial fields in 1999 and 2000. Spectral variables derived from SPOT images and aerial images were strongly correlated when the field had large spatial variability in crop development, and weakly correlated when the crop was more uniform. Vegetation indices (NDVI, Green NDVI) derived from SPOT images were significantly correlated with SPAD readings in both fields. The correlation between SPOT images and SPAD readings was similar to that between aerial images and SPAD readings, indicating that SPOT images may have potential for detecting chlorophyll levels and nitrogen stress in corn.