Alternative NDVI combination in maize grain yield estimation

Given the importance of maize production and the wide variation in productivity, early yield estimation might be essential. Several technological devices recently became available and have proven useful in analyzing yield and yield-related traits. In this research, an active multispectral proximal sensor, the Plant-O-Meter (POM), was used in the field trial to provide early yield estimates. The maize crop was grown under field trial conditions with four different levels of nitrogen apply. The purpose of this study was to examine at the effects of three different NDVIs: normalized difference vegetation indices (NDVI), Green NDVI (GNDVI), and Blue NDVI (BNDVI) on maize grain yield estimation over the season. Maize canopy reflectance and various NDVI values were assessed from the fourth leaf growth stage (V4) to the end of the blister stage (R2). Pearson's correlation coefficient (r) was used to evaluate the correlations between grain yield and the various NDVIs obtained throughout the season. Maize grain yield showed a significant positive relationship with various NDVIs throughout the early vegetative stages. The most significant correlation was found between the eight and nine leaf growth stages (V8/V9) and the four leaf growth stage of maize (V4). Among various NDVIs, the BNDVI showed the greatest positive and significant correlation with grain yield. The findings of this study suggest that NDVI measurements could be a useful indicator for assisting in early crop yield estimations.