EFFECTIVE CULTIVATION OF EXTRA-EARLY SOYBEAN CULTIVAR CV. ‘VNIIOZ 86’ UNDER IRRIGATION

The influence of sowing methods and irrigation regimes on productivity of extra-early soybean cultivar VNIIOZ 86 has been studied at Russian Research Institute of Irrigated Agriculture. The use of differential irrigation regimes (70-80-70% and 80-80-70% of FMC) resulted in 2.42 ... 2.51 t/ha yield and mid-level profitability of grain production (80.6%), which was 0.25 ... 0.34 t/ha more compared to the control (80-80-80% of FMC), as synchronization of vegetative growth and reproductive development increased grain amount in total biomass up to 36.2%. Differential irrigation regimes restrained an increase in crude protein level in the seeds (at the level of 35.4 ... 41.2%) compared with the control (36.5 ... 41%). However, they increased fat content in the seeds (18.1 ... 21.4%) compared to the control variant (16.1 ... 18.6%). Optimization of irrigation regime increased protein (up to 0.68 ... 0.94 t/ha) and fat (0.37 ... 0.46 t/ha) compared to the control (0.64 ... 0.83 t/ha and 0.29 ... 0.35 t/ha, respectively). The smallest water consumption coefficient was observed in sites with differential irrigation regimes - 1,174 ... 1,524 m3/t, when in the control site it was 1,651 ... 1,977 m3/t. Extra-early VNIIOZ 86 plants require 8 ... 14 irrigations at a rate of 190 ... 230 m3/ha. It is enough to perform 8 irrigations in relatively favorable years (2013), and up to 14 irrigations in dry years (2014- 2015). To maintain a differential irrigation regime, it is necessary to perform 8 ... 10 irrigations in wet and up to 10 ... 13 irrigations in dry years. The highly profitable cultivation of early soybeans (107.9%) was achieved using drilled sowing (0.30 × 0.042 m) that resulted in significant yield increase (up to 3.02 t/ha) which was 0.41 t/ha higher compared to wide-space sowing technique (0.70 × 0.024 m).