Normalized Difference Vegetation Index (NDVI) in Assessment of Grain Crop State

Abstract

The results of studying the dynamics of the NDVI of winter triticale crops in the conditions of the Northwest of Russia are presented. The NDVI was determined based on remote sensing data obtained by two methods including satellite imagery and aerial photography from an unmanned aerial vehicle (UAV). The analysis of the dynamics of the NDVI of the surveyed area for the period from May 15 to August 8, obtained from the Sentinel-2 L2A satellite, showed the dependence of the index on the increase in biomass of winter triticale by the periods of its growth and development, as well as on the meteorological conditions of the growing seasons. The sharpest increase in the vegetation index was noted in the period from the beginning of June to the beginning of July, which corresponds to the phase of entering the tube — filling of winter triticale grain. In the most favorable weather conditions, the vegetation index reached 1.0, which indicates the formation of dense vegetation by triticale crops. It is confirmed that the strong dependence of the average NDVI on yield occurs against the background of a decrease in the value of the vegetation index. The conducted aerial photography showed the presence of spatial heterogeneity in the studied fields, which caused uneven growth and development of winter triticale plants within the boundaries of one field. The shortage of grain from each hectare will be about 200 kg. In this regard, it is recommended to apply precision farming using NDVI mapping schemes with reference to point-based field surveys.