Relationship Between Coefficient of Variation Measured by Spectral Reflectance and Plant Density at Early Growth Stages

Abstract

Nitrogen use efficiency (NUE) is estimated to be 33% throughout the world, current precision nitrogen application through precision sensing methods can improve NUE to a level of 50%. Statistical analysis of sensor data has not yet been evaluated for using in improving the prediction of potential yield. This study was conducted to evaluate the effect of plant population on the CV of early season NDVI values. Also evaluated in this study was the effect of seed row direction in relation to sensing direction on NDVI values. In 2003-2004 the relationship between the CV of NDVI values and plant population was determined. From this relationship a critical CV value was determined to be 20. Also observed was the trend that CV follows over time. This tend was shown to hold true across nitrogen treatments. Sensing direction was shown to have no effect upon NDVI readings across seven site-years with multiple varieties, seeding rates, nitrogen rates and growth stages.