Changes in Moisture Reserves in Leached Chernozem during the Nongrowing Period, Depending on the Preceding Crop and Basic Cultivation

Researches to study changes in productive moisture reserves in leached low-humus medium loamy chernozem during the nongrowing period of spring wheat, depending on the preceding crop and methods of basic tillage, were performed in 2011–2021 in the forest-steppe of southwestern Siberia on a southeastern slope 1–2° steep. The fallow–wheat–oats–wheat–pea–wheat crop rotation and permanent wheat crops in the variants of zero tillage and shallow (14–16 cm) and deep (25–27 cm) subsurface plowing were analyzed. Moisture reserves in the upper 1-m-thick soil layer in autumn were determined by preceding crops (65.7%) and their interaction with cultivation methods (30.9%). They decreased from fallow (109.2 mm) to pea (88.1 mm), oats (82.4 mm), and permanent wheat (72.6 mm) as well as from deep (91.4 mm) to shallow (88.7 mm) and zero (84.0 mm) cultivation. In early spring, moisture reserves were mainly determined by the cultivation method (81%), decreasing from deep (169.4 mm) to shallow (145.8 mm) and zero (118.4 mm) plowing and from fallow (156.6 mm) to pea (144.4 mm), oats (140.0 mm), and permanent wheat (136.9 mm). The accumulation of winter precipitation by soil was determined by the cultivation method (81.0%), decreasing from deep (77.9 mm) to shallow (57.0 mm) and zero (34.4 mm) treatment and increasing from fallow (47.5 mm) to pea (56.3 mm), oats (57.7 mm), and permanent wheat (64.3 mm). By the germination period, moisture reserves in the soil decreased, depending on the cultivation approach (87.6%), from deep (120.1 mm) to shallow (108.5 mm) and zero (100.5 mm) plowing. Moisture losses in spring on an unplowed background were minimal (81.2–87.5 mm) and increased on backgrounds with shallow and deep plowing (92.8–117.8 and 101.0–135.2 mm, respectively) and from permanent wheat to oats, pea, and fallow.