The impact of anthropogenically -controlled factors on the formation of root mass and yield of rice under drip irrigation in the lower volga region

The results of studies on the influence of water or nutrient regimes of the soil on the formation of the root system of rice when watering drip system. Thus, while maintaining the water regime of the soil not less than 80% of HB in the 0.6 m layer, the root mass was in the three years in the 0.4 m layer – 4.96, and 0.6 m - 5.64 t/ha. In the variant where soil moisture was maintained at least 80% HB and the depth of soil wetting until the end of the tillering phase by 0.4 with a further decrease to 0.6 m, the plants differed in maximum foliage and habitus, which contributed to an increase in the root mass of aerobic rice in the layer of 0.4 m to 5.40, and in the layer of 0.6 m – 6.14 t/ha. In the variant of the water regime of the soil with a moisture content of not less than 80% HB from sowing to the end of the tillering phase in a layer of 0.4 m, followed by a decrease to 0.6 m, and from wax to full ripeness of grain not less than 70% HB the volume of roots compared to the second option for three years in a layer of 0.4 m became less by 0.18 t/ha, and in a layer of 0.6 – 0.20 t/ha, but more than the first in a layer of 0.4 m by 0.26 m and 0.6 m – 0.30 t/ha. Also had a great influence on the root system of aerobic rice. Thus, its lowest value, 5.46 t/ha for the three years, was formed when making N₉₅P₆₂K₇₅ (5 t/ha). Making N₁₁₄P₇₄K₉₀ (6 t/ha) increased root weight by 0.48 t/ha regarding the N₉₅P₆₂K₇₅ dose (5 t/ha), but was below making N₁₃₇P₉₀K₁₀₈ (7 t/ha) – 0.60 t/ha. In the result of the conducted researches it was established that maximum yield of grain (of 6.95 t/ha) was obtained in variant water regime of soil 80% of NV in layers of 0.4 and 0.6 m, making N₁₃₇P₉₀K₁₀₈ (7 t/ha). The minimum yield, 4.88 t/ha, was obtained in the variant of soil water regime of 80% of NV in a layer of 0.6 m with the introduction of N₉₅P₆₂K₇₅ (5 t/ha).