Relationships between the NDVI, Yield of Spring Wheat, and Properties of the Plow Horizon of Eluviated Clay-Illuvial Chernozems and Dark Gray Soils

— On the Cis-Salair Plain with well-drained soils, the statistical dependence of the yield of spring wheat and NDVI on some properties of the plow horizon in eluviated clay-illuvial agrochernozems (Luvic Greyzemic Chernozems) and agro-dark gray soils (Luvic Retic Greyzemic Phaeozems) was studied. In the regression model, the NDVI was shown to be responsible for 85% of the variation in the yield of spring wheat. Using the model and the spatial distribution of NDVI as the cartographic base, the prediction and visualization of the spatial variability of the spring wheat yield was performed. The spring wheat productivity and the NDVI proved to be insignificantly different for the agro-dark gray soils and agrochernozems. The correlation was significant between the yield of spring wheat and the NDVI, on one hand, and the pre-sowing water content ( r = 0.52; r = 0.57) and the content of exchangeable potassium ( r s = 0.58; r s = 0.61), on the other hand; the correlation with the contents of humus ( r = 0.35; r = 0.38), available phosphorus ( r s = 0.32; r s = 0.35), and mobile zinc ( r s = 0.42; r s = 0.48) was moderate. Relatively high contents of mobile forms of macro- and microelements in soils correlated with higher values of the presowing water content.