INFLUENCE OF MINERAL AND ORGANO‑MINERAL FERTILIZERS ON THE AGROCHEMICAL PROPERTIES OF AGROCHERNOZEMS AT THE “AGROLANDSCAPE” TEST SITE

Abstract

Fertilizers play a key role in improving the sustainability of grain production. At the “Agrolandscape” testing site, under conditions of unstable moisture in the Central Ciscaucasia, studies were conducted in 2023–2025 to compare the effects of mineral and organo-mineral fertilizers in various taxa (interfluve plain edge, upper and lower slopes) on the effective fertility of agrochernozems in the second wheat crop. It was found that the studied fertilizers had little effect on the content of humus, nitrate nitrogen, and pH. The leading influence on these parameters belongs to the position in the landscape (99,0; 25,0 and 98,5%, respectively). A significant influence of the position in the landscape was noted – 93,5% on the amount of K₂O. The fertilizer dose has a significant impact on this parameter. A significant increase in K₂O content at the edge of the interfluve plain with mineral fertilizers begins with a dose of N₆₀P₆₀K₆₀ and above, and with OMF – with N₉₀P₉₀K₉₀ and above. At the upper slope, positive changes were observed with a dose of N₆₀P₆₀K₆₀ in both mineral and organo-mineral fertilizer treatments. At the lower slope, all doses of mineral fertilizers, including N₃₀P₃₀K₃₀, were effective, while in the OMF treatments, the effect was observed starting with a dose of N₆₀P₆₀K₆₀ and above. The greatest positive impact on P₂O₅ content was exerted by the dose of applied fertilizers, equal to 78,4%, while topography position contributed only 4,5%, and fertilizer type contributed 2,1%. The effect of mineral fertilizers was more noticeable. At the edge of the interfluve plain (taxon А₁) and the lower slope (А₃), all doses of mineral and organo-mineral fertilizers, with the exception of the OMF treatment at a dose of N₃₀P₃₀K₃₀, had a significant effect on the amount of P₂O₅. On taxon А₂ (upper slope), all treatments significantly increased the amount of mobile phosphorus in the soil.