Relating AEROCam-derived NDVI to apparent soil electrical conductivity (ECa) for corn fields in Wyoming, USA

High-spatial-resolution aerial images are necessary to capture variations in crop growth in small fields. The objective of this study was to analyse the relationship between the normalized difference vegetation index (NDVI), derived from Airborne Environmental Research and Observation Camera (AEROCam; 1 m colour infrared) images, and the apparent soil electrical conductivity (ECa) values measured in furrow-and sprinkler-irrigated fields planted with corn (Zea mays L.) in Lingle, Wyoming. NDVI, calculated using 2005, 2006 and 2007 AEROCam images, and ECa were selected, as both variables are used as a measure of potential crop yield. NDVI values exhibited statistically significant exponential relationships with the ECa values for both fields. For the furrow-irrigated field, the adjusted R-2 values ranged between 0.66 and 0.79, and for the sprinkler-irrigated field the adjusted R-2 values ranged between 0.64 and 0.91. Results obtained in this study indicate that AEROCam images can be used for monitoring crop growth in small fields and can provide valuable insights about crop growth patterns when ECa measurements are not available.