УСТОЙЧИВОСТЬ АГРОЦЕНОЗОВ ЯРОВОЙ ПШЕНИЦЫ К СОВРЕМЕННЫМ КЛИМАТИЧЕСКИМ ИЗМЕНЕНИЯМ В ЗЕМЛЕДЕЛИИ СТЕПНОЙ ЗОНЫ ЮЖНОГО УРАЛА

The assessment of current meteorological trends is necessary for the scientific justification of measures aimed at stabilizing the gross harvest of food grain under conditions of changing climate. The purpose of the research was to assess the impact of climatic changes on the survival rate and safety of productive spring wheat crops until harvesting on the example of some administrative districts (natural and climatic zones) of the Orenburg region. Data on the average daily air temperatures, precipitation and yield of spring wheat during 2008–2019 obtained from open sources were the objects of the research. The average loss of the harvest area of spring wheat in the region, which amounted to 16.9 % of the sown area, for the analyzed period (2008–2019) was equal to 237,160 hectares per year. Its highest relative values were observed in Akbulaksky (45.7 %), Orenburg (40.0 %) and Dombarovsky (38.2 %) districts. The territories with the largest proportions of unharvested areas are characterized by rather “harsh” hydrothermal conditions. The average values of the Selyaninov Hydrothermal Coefficient (HTC) over twelve years were 0.57 mm/°С, 0.48 mm/°С and 0.42 mm/°С in the central, eastern and southern zone of the region, respectively. In the studied zones, there is a clear increase in the aridity of summer months (the growing seasons of spring wheat), especially in the southern zone, where the moisture conditions are characterized as dry. The strongest inverse relationship between the loss of spring wheat harvesting areas and the amount of precipitation (r = −0.50 – −0.71) is observed for the period September–July. The direct relationship between the loss of spring wheat harvesting areas and the sum of active temperatures is the strongest in the April-June period (r = 0.40–0.59). It coincides with the time of seedlings formation and reproductive organs laying, which are the basis of the future crop. To stabilize the gross grain harvest, it is appropriate to carry out a set of organizational, economic and agrotechnical measures aimed at optimizing the structure of the land fund and adapting agricultural technologies to the changing climate.