The effect of prolonged use of soil-protective technologies on the changes of agrochemical characteristics of the fertility of eroded ordinary chernozems of the Western Ciscaucasia

The article presents the results of long-term observations of humus content in the soil and mobile forms of main nutrients (nitrogen, phosphorus, potassium). The researches were carried out on the basis of long-term stationary crop rotation, in which the traditional and soil-protective technologies of cultivation of agricultural crops were compared. It was determined that over the last decade the reserves of mobile phosphorus in the plow layer were decreasing when the soil-protective and traditional technologies were used by 3.3 and 3.5 % per year, respectively. The speed of decreasing of reserves of exchangeable potassium in the plowing horizon (0-30 cm) was according to variants 0.9 and 1.4 % per year, respectively. The transition from the 13-field crop rotation to the short (8-field) rotation along with the cancellation of mineral fertilizers applied for primary tillage has reduced the humus content in the soil layer of 0-40 cm from 4.04-4.10 % in 1999 to 3.84-3.89 % in 2008.