THE IMPACT OF INOCULATION AND FOLIAR APPLICATION OF IRRIGATED SOYBEAN CROPS ON SYMBIOTIC ACTIVITY AND PRODUCTIVITY IN THE VOLGA-DON INTERFLUVE

Purpose: to study the impact of pre-sowing inoculation and foliar application of preparations of various origins (chemical, natural and biological) on the symbiotic activity of irrigated soybeans. Materials and methods. The studies were conducted on light chestnut soils of the Volgograd region. A two-factor experiment was designed: factor A – pre-sowing inoculation of soybean seeds, factor B – foliar treatment of crops. Statistical processing of the experimental data was carried out according to the method of B. A. Dospekhov. Results. It was found that in plots with the inoculant application for pre-treatment of seeds, the number of nodules per plant reached 18, while in the control variant without inoculation – only 16 on average over three years of observations. A similar pattern was observed in the nodule weight per plant: 0.152 g in the first case and 0.129 g in the second. When using various foliar applications, an increase in the symbiotic apparatus indices on soybean roots was observed, especially when using the biocomplex: 29 nodules per plant versus 23, and the nodule weight was 0.216 and 0.157 g, respectively. Furthermore, in the variants with seed inoculation and the use of the biocomplex for foliar application, the maximum values of the plant leaf surface area were observed – 27.70 thousand sq. m/ha. Conclusion. The maximum soybean yield was obtained with the combined use of seed inoculation and foliar treatment of plants with a biocomplex, which ensured a grain yield of 3.91 t/ha.