Reserves of productive water in the soil for growing winter wheat

Abstract

An analysis of the productive water reserves in the soil at the time of sowing and harvesting of winter wheat cultivated after different preceding crops was carried out. The worst conditions for the water accumulation in the 0–30 cm, 0–50 cm, and 0–100 cm soil layers were created after pea for grain — 5.3 mm, 8.7 mm, and 21.6 mm, respectively, in the soil layers; after soybean — 6.0 mm, 11.7 mm and 28.1 mm, respectively; corn for silage — 4.5 mm, 7.4 mm and 13.3 mm, respectively. Earthing the rye and oat mix and green manure made it possible to accumulate 32.9 mm and 29.9 mm of productive water reserve in the 0–100 cm layer, which can be explained by the earlier clearance of the field before the time of sowing winter wheat. In the link of crop rotation with bare fallow, the reserve of productive water in the 0–100 cm soil layer were the highest and amounted to 74.4 mm, which exceeded the link with corn for silage 5.6 times, with pea for grain and perennial grasses 2.6 and 3.4 times. In the link with soybean, the reserve of productive water in the 0–100 cm soil layer amounted to 28.1 mm, which can be explained by the low yield of this crop in this zone. It should also be taken into account that of all the studied preceding crops, soybean is harvested the latest; therefore, it is not always possible to prepare the soil well for sowing winter wheat. During the period of harvesting winter wheat, the reserve of productive water in the soil depended less on preceding crop. At the same time, in the 0–100 cm soil layer, the highest reserves of productive water were formed in the of crop rotation links with bare fallow — 41.1 mm, perennial grasses — 33.6 mm, vetch and oat mix for green manure and green fodder — 29.3 and 31.4 mm, respectively; the lowest — in the links with pea for grain, soybean and corn for silage: 26.5, 26.9, and 24.9 mm, respectively. The yield of winter wheat in the link with bare fallow was 6.52 t/ha, which by 0.80–0.99 t/ha exceeded the other links of crop rotation.