Productivity of crop rotation with long-term use of mineral fertilizers in the changing climatic conditions of the steppe Volga region
The paper analyzes the results of the effectiveness of the use of various systems of mineral fertilizers in the six-field crop rotation, obtained under conditions of long-term stationary experience for the period 1969-2018. The nature and degree of influence of the changing agro-climatic conditions of the Volga steppe zone on the productivity of crop rotation on both fertilized and non-fertilized variants of the experiment have been established. In the period from I-IV to V-VIII rotation, there was an increase in the sum of active temperatures for May-July, an increase in the average daily air temperature in July by an average of 1.1 °C, a decrease in hydrothermal coefficient values. The increase in aridity of the climate had a negative impact on the effectiveness of various fertilizer systems in the experiment. There is a tendency to decrease the productivity of crop rotation in the period from I-IV to V-VIII rotation. At the same time, there is an increase in the share of increases in the resulting crop from the use of mineral fertilizers. The most effective in the experiment were medium and high doses of nitrogen-phosphorus fertilizers.