AGROCLIMATIC FACTORS AND PRODUCTIVITY OF DIFFERENT MATURITY GROUPS SOYBEAN CULTIVARS UNDER ENDOPHYTIC-RHIZOBIAL INOCULATION IN CONDITIONS OF NON-IRRIGATED AGRICULTURE OF THE SOUTHERN STEPPE OF UKRAINE

Abstract

The article presents the results of studies of weather and climatic conditions during the production processes in the period of formation of the yield of soybean varieties of different maturity under pre-sowing endophytic-rhizobial inoculation of seeds, as well as the functional activity of the rhizosphere microbiota and plant productivity in conditions of non-irrigated agriculture. The average temperature, relative humidity, and rainfall were determined for the interphase periods, which are the main indicators that affect the evapotranspiration, moisture deficit, and moisture coefficient. The experiments were conducted at the experimental field of the Odesa State Agricultural Research Station, located in the southern steppe zone of Ukraine. The soil of the experimental field is a heavy loamy southern chernozem. The moisture availability indicators show that the southern part of the Steppe zone of Odesa region during the growing season of crops (April-September) in 2023 belonged to the semi-arid zone, and in July and September - to the desert. Evapotranspiration and moisture deficit during the growing season of plants of both soybean varieties (ultra-early maturing Diona and mid-season Sviatohor) varied significantly and depended on the average monthly temperature, relative humidity and rainfall. Evapotranspiration reached 1045.1-1244.0 mm, resulting in a moisture deficit of 913.3-1100.4 mm. Due to insufficient rainfall in June, July and August, most crops experienced an increase in moisture deficit. The use of complex thermotolerant and drought-resistant microbial inoculants with stress-protective functions reduced the negative impact of agroclimatic factors on soybean plants and rhizosphere microbiota. The main directions of scientific and economic activity for obtaining consistently high crop yields in the southern part of the Steppe zone are the structuring of sown areas with an optimal share of irrigated land and the use of innovative biological preparations.