Продуктивная влага и урожайность озимой пшеницы в сухостепной полосе Ставрополья

Rational use of moisture by crops in conditions of its lack is an urgent task of agriculture. The research was carried out in the agriculture department of the Prikumsk experimental selection station in 2014–2020 in a 6-field grain-fallow crop rotation. The purpose of the research is to study the moisture supply of winter wheat crops by various predecessors. The main difference in the moisture content of fallow and non-fallow crops was observed in the autumn period. The content of productive moisture in a meter layer of soil before sowing in a pure fallow is 2.4 times higher than in a semi-fallow. In favorable years for humidification (2014–2016), the moisture reserves in the arable soil layer (0–20 cm) by their predecessors practically did not differ (24.6 and 23.5 mm), while in dry years (2017–2020) they differed significantly (10.8 and 4.1 mm). The formation of the yield for pure fallow was significantly influenced by moisture reserves for sowing winter wheat in the arable ( r = 0.86) and 1 m soil layer ( r = 0.80), precipitation in April and May ( r = 0.77), May ( r = 0.75) and the total moisture supply of crops ( r = 0.91), and for the semifallow — the total moisture  supply ( r = 0.80). The accumulation of moisture in the cold period depended on its autumn content in the 1st soil layer, had a significant negative relationship for the pure vapor ( r = -0.79 in mm and -0.85 in %) and manifested itself as a tendency for the semi-vapor ( r = -0.70 and -0.69). The greater the autumn reserves of moisture in the soil, the less its amount accumulated over the winter and, conversely, the greatest replenishment of moisture was observed with the minimum autumn reserves. The efficiency of using moisture by fallow crops was 1.7 times, and the yield was 1.9 times higher compared to the non-steam predecessor.