Normalized Differential Vegetation Index of Winter Wheat Depending on the Rates of Nitrogen Fertilizer and Nitrification Inhibitor

Abstract

The article presents the results of experimental studies of the relationship between the normalized differential vegetation index and the yield of winter wheat at different rates of nitrogen fertilizers and the nitrification inhibitor 3,4-dimethylpyrazole phosphate with сarbamide-ammonia mixture (CAM-32). Field research was carried out in 2018-2021 in the research department of the Limited Liability Agricultural Company (LLAC) "Druzhba Nova" of the Varvyn district of the Chernihiv region (department of the «Kernel» agricultural holding). Analytical and mathematical and statistical methods were used to process experimental data. The normalized differential vegetation index (NDWI) was determined from the satellite images of WorldView-2, WorldView-3, Geoeye-1 (Maxar USA). The scheme of the one-factor field experiment was the use of options with different rates of nitrogen fertilizers (N100 and N120), as well as the use of the nitrification inhibitor 3,4-dimethylpyrazole phosphate in mixture to CAM-32. The control (backgroung) option was the application of fertilizers at the rate of N10P30K40. The results of experimental studies proved that NDWI is directly correlated with the yield of winter wheat for all 4 years of research. It was established that the NDWI, on average over three summer months, was higher in 2018 in the range of 0,56-0,67 and in 2020 – 0,53-0,66. The yield of winter wheat was also higher in 2018 and 2020, namely: in 2018 from 3,72 t/ha to 8,14 t/ha and in 2020 – from 3,77 t/ha to 7,25 t/ha. The NDWI, in 2019 and 2021, averaged over three summer months according to the experiment options was lower and amounted to 0,33-0,38 in 2019, and 0,30-0,33 in 2021. This trend correlates with winter wheat yields, which were also low during this period. So, in 2019 it was 3,63 t/ha – 5,10 t/ha and in 2021 – 3,83–4,81 t/ha. The correlation coefficient between NDWI and the yield of winter wheat was high: in July and August, it was from 0,93 to 0,97 on the options with nitrogen fertilizer rates N100 and N120.