Natural variability within corn (Zea mays L.) production systems is a common observance, but the resolution at which this variability occurs and the methods of nitrogen (N) fertilization currently employed fail to factor in the spatial difference among corn plants. The objective of this study was to estimate the yield of each plant by collecting the normalized difference vegetative index (NDVI) using a GreenSeeker™ optical sensor. NDVI readings were collected every 1.2 cm in rows 15 to 30 m in length. Knowing the exact location of each plant, the average NDVI value was calculated by assuming that each plant occupies half the distance between it and its neighbors. As NDVI values were collected, it was clear that differences in plants could be detected using an optical sensor. By-plant yield (based on the specific area occupied) was correlated with by-plant NDVI. At the V8 growth stage, NDVI alone was a good predictor of plant biomass, while a second dimension, height, further refined yield prediction. It is clear from this work that precision solutions for nutrient management can be made at the by-plant level to address the large spatial variability present in corn.
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