The study aimed to investigate the relationship between the NDVI vegetation index and the carbon absorption capacity of winter wheat crops to develop remote sensing methods for estimating the accumulated amount of carbon. The work was carried out in the unstable moisture zone of Stavropol krai from 2015 to 2018. Three field experiments were laid out. Experiment 1 involved a study of different forecrops (factor A), specifically, winter wheat and fallow; mineral nutrition levels (factor B), specifically, no fertilizers (control) and N90P60K60; and the varieties (factor C) Zustrich, Arsenal, Stavka, and Stat’. Experiment 2 examined different sowing dates (factor A), early, middle, and late, and varieties (factor B) Zustrich, Arsenal, Stavka, and Stat’. Experiment 3 involved seeding rates (factor A), specifically, 4, 5, and 6 million viable seeds per 1 ha and varieties (factor B) Zustrich, Arsenal, Stavka, and Stat’. The main indicators of photosynthetic productivity, that is, the vegetation index NDVI and the amount of carbon accumulated by winter wheat crops, were determined. A significant relationship was established between the values of the indicators of photosynthetic productivity and NDVI (most of the correlation coefficients are reliable at the significance level of p = 0.01 and range from 0.46 to 0.74). The relationship between the amount of carbon accumulated by crops and the NDVI value is significant at p = 0.05 and is characterized by the following correlation coefficients: 0.75 in the booting phase (maximum NDVI), 0.51 in the heading phase, and 0.65 on average for the growing season. The results obtained in the experiment open up possibilities for using the NDVI vegetation index in assessing the carbon absorption capacity of winter wheat crops and other agricultural crops.
Eroshenko et al. (Fri,) studied this question.