Normalized Difference Vegetative Index Used to Identify Spatial Variability in Vegetative Growth and Grain Yield of Corn
2012
Henik, Joshua J. | Knapp, Allen D. | Moore, Kenneth J. | Lee Burras, C.
Recognizing variability in plant growth early can aid in identifying yield-limiting factors such as soil conditions, nutrient availability, and/or environmental limitations. Active sensors have been used to gather reflectance data from crop canopies and used to calculate Normalized Difference Vegetative Index (NDVI) which has been associated with percentage ground cover, leaf area index, biomass accumulation, and nitrogen use efficiency. The objective of this study was to show that NDVI can be used to characterize spatial variability in plant growth and is correlated with grain yield. NDVI values were measured biweekly throughout the growing seasons of 2010 and 2011 in corn grown at a location with soil and topographic variability. Grain yield was measured after each growing season. Two cropping rotations were used: continuous corn, and a corn-soybean-small grain/soybean double crop. Differences in corn growth at different landscape positions could be identified with NDVI eight weeks following planting (P≤ 0.10). A relationship was established between NDVI and grain yield eight weeks following planting (r²> 0.80). NDVI could be used to identify the variability of grain yield in continuous corn production when measurements were taken after the accumulation of 800 to 900 growing degree days.
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