INFLUENCE OF MOISTURE SUPPLY DURING THE GROWING PERIOD ON PRODUCTIVITY AND FODDER VALUE OF SOYBEAN

The paper presents the results of research on comparative study of seed yield formation and aboveground biomass yield of soybean in years with different moisture availability, under the conditions of the Central region of the Non-Chernozem zone of Russia. It has been found that the maximum accumulation of both raw and dry aboveground biomass, crude protein and fodder units in soybean agrocenosis is observed at the stage of full seed (R6). The average values for maximum yields in the experiment were the following: of aboveground raw biomass – 24.8 t/ha, aboveground dry biomass – 6.82 t/ha, protein yield in aboveground dry biomass – 1 278 kg/ha, yield in fodder units – 3.68 t/ha, the contribution of leaves to the yield of aboveground dry biomass being 23.0%, leaves accumulated 20.0% of protein where its content being 20.9%; the contribution of stems to the yield of aboveground dry biomass was 36.0%, stems provided 11.0% of protein accumulated where its content being 5.8%; the contribution of beans reached 41.0%, beans ensured 69.0% of crude protein where its content being 30.1%. Increased moisture availability contributed to a significant growth of the yield of aboveground raw biomass – 1.09-1.19-fold, aboveground dry biomass – 1.08-1.15-fold, protein yield in aboveground dry biomass – 1.10-1.21-fold, yield in fodder units in aboveground dry biomass – 1.07-1.14-fold. On average in the experiment seed yield reached 2.54 t/ha, yield of protein accumulated in seeds was 1 008 kg/ha, of fodder units – 3.40 t/ha. Increased level of available moisture contributed to increase in seed yield – by 1.14-1.21 times, collection of crude protein per unit area – by 1.19-1.31 times, yield of fodder units – by 1.13-1.21 times. It was found that the yield of aboveground biomass harvested at the stage of full seed (R6) significantly exceeded the seed yield: in terms of dry matter yield – by 2.69 times, protein yield – by 1.27 times, fodder units yield – by 1.08 times.