Changes in agrochemical properties of meadow chernozem-like soil under prolonged exposure to agrogenic factors in grain-soybean crop rotation

In a long-term stationary experiment to study the fertilizer system in crop rotation, established in 1962–1964 on meadow chernozem-like soil in the southern natural and climatic zone of the Amur region, the influence of prolonged use of mineral and organo-mineral fertilizer systems on the agrochemical properties of meadow chernozem-like soil in relation to the level of crop yield in crop rotation was studied. The use of mineral fertilizers alone and together with organic ones provided an increase in the content of mobile phosphorus in the soil by 2.0–2.5 times, its mobility by 2.9–3.5 times relative to control. The long-term use of the organo-mineral fertilizer system led to an increase in the humus content by 0.69% and the preservation of acidity indicators at the initial level, while the application of only mineral fertilizers increased the hydrolytic and metabolic acidity. Wheat yield when applying N30 against the background of prolonged application of fertilizers to the 12th rotation of the crop rotation increased by 0.58 t/ha relative to the control, with its aftereffect – by 0.30 t/ha. At the same time, the yield of soybeans was 2.42–2.62 t/ha. It was found that the productivity of crop rotation was determined by 73% by changes in humus content, soil acid content and mobile P2O5 content in the 0–20 cm soil layer. The relationship of crop rotation productivity with humus content was weak (β = 0.26), hydrolytic acidity – medium reverse (β = –0.57), metabolic acidity – strong reverse (β = –0.81) and phosphorus content – strong (β = 0.84). The values of p-levels and Student coefficients indicated the fact that hydrolytic and metabolic acidity, the content of mobile phosphorus were statistically significant variables.