Corn OSAVI as related to soil electrical conductivity and nitrogen fertilization rates

Soil electrical conductivity (SEC) surveys have recently become available for the characterization of soil patterns within fields. The question arises as to whether or not SEC maps can be used to drive site-specific nitrogen (N) fertilizer applications during the growing season. Corn was grown with N fertilization treatments ranging from 0 to 150 kg N/ha at topdressing. CASI airborne images were collected using a multispectral mode of operation, with 1 m spatial resolution and computed to provide an Optimized Soil-Adjusted Vegetation Index (OSAVI). Low SEC were related to high OSAVI. There were neither effects of N fertilization on OSAVI nor interaction with SEC properties. It is concluded that (1) N application at topdressing may not impact corn growth and (2) that variable rate N application can hardly be based on SEC patterns.