CHANGES IN REGIONAL CLIMATIC CONDITIONS AND PRODUCTIVITY OF WINTER WHEAT IN THE STEPPE ZONE OF EUROPEAN RUSSIA

Abstract

Monitoring of climatic conditions is necessary to determine the degree of their change and to develop methods for optimizing the interaction of natural and socio-economic systems aimed at maintaining food security without harming the environment. The purpose of the research was to analyze long-term climatic trends and assess their impact on the productivity of winter wheat in the model regions (Orenburg and Volgograd regions) of the steppe zone of European Russia for the period from 1990 to 2020. Statistical processing was carried out by the method of correlation and regression analysis. The variability of the studied meteorological parameters and the yield of winter wheat over the years was estimated using the coefficient of variation. The positive dynamics of the average daily air temperature was revealed. It was 1.6–2.3 °С on average per year, 2.5–3.5 °С during the autumn growing season (August–September) and 1.1–2.4 °С in spring-summer growing season (April–June). A steady precipitation decrease in the warm period of the year in the Orenburg region (by 32 mm) and their zero balance in the Volgograd region against the background of an increased sum of active temperatures or growing degree days (by 395–580 °С) led to a decrease in the Selyaninov Hydrothermal Coefficient (HTC) by 0.15–0.20 units. In some periods of vegetation, the HTC values approached the level “dry” in the cultivation zone assessment. Typically, winter wheat productivity depends on zonal features. In the Volgograd region, grain yield exceeding the average (2.32 t/ha) was obtained in 52.3 % of years; in the Orenburg region (1.61 t/ha) – in 47.6 % of years. The yield that amounted to 75% of the maximum was noted in 33.2 % of years in the Volgograd region, in the Orenburg region – in 14.3 % of years (all-Russian indicator – 38.1 %). The realization of the biological productivity of winter wheat is more related to the amount of precipitation, which determines 40.6% (Volgograd region) and 44.2% (Orenburg region) of its variations. In the Orenburg region, annual precipitation in general and those of the cold period have priority; in the Volgograd region – annual precipitation and precipitation of the spring-summer period.