Expression of Spatial Variability in Corn (Zea Mays L.) as Influenced by Growth Stage Using Optical Sensor Measurements

Abstract

The time at which remote sensing technology can quantify differences in corn plants should be the time at which the CV of the measured data is the highest. At that growth stage, the corn produces the greatest amount of expressed variability. The relationship of NDVI with grain and biomass yields can be used to determine the most appropriate time for management based on sensor technology. Also, if sensors have the ability to indirectly determine plant spacing and to determine the CV of data collected, it could greatly improve yield prediction based on NDVI alone over fixed distances. The documentation of CV over time in corn produced similar trends over all years and locations in which the initial peak in CV occurred around the V6 to V7 growth stage. A second peak also occurred in the late reproductive growth stages. Based on these results, the peak at V6 to V7 is the growth stage at which the greatest amount of variability is expressed by corn. The relationship if NDVI to grain and biomass yields showed that the V8 growth stage had the highest correlation with yield. It was also found that CV is positively related to plant spacing. This study showed that the best time to recognize variability, predict grain and biomass yields, and determine plant spacing is at the V8 growth stage.