IMPACT OF PRIMARY TILLAGE ON HYDROPHYSICAL PROPERTIES OF DARK CHESTNUT SOIL AND CHICKPEA (CICER) YIELD

Purpose: to study the impact of the primary tillage methods of dark chestnut soil on the bulk density, water permeability, moisture meter layer and chickpea yield. Materials and methods: studies were carried out on dark chestnut soil in 2016–2019 (Saratov region). The soil density was determined according to GOST 12536-79, soil moisture – according to GOST 28268-89. The trial establishment and the mathematical processing of digital material were carried out in accordance with “Field Experience Methodology” (B. A. Dospekhov, 1985). Results: four-year observations of hydrophysical properties showed that before chickpea sowing, the maximum value of the arable layer density (0–0.3 m) was recorded in the variants with minimal tillage with a disc harrow (1.26 grams per cubic centimeter). The lowest values of soil density were noted in variants with combined and moldboard tillage (1.09–1.10 grams per cubic centimeter, which is 14–15 % less than the minimum tillage). Water permeability of dark chestnut medium loamy soil increased from minimal tillage (71.1 mm per h) to subsurface (107.2 mm per h), combined (126.4 mm per h) and moldboard one (126.5 mm per h). Before chickpea sowing, the highest soil moisture in the meter-long layer was observed during non-mold and combined cultivations (17.5 % of the mass of absolutely dry soil, which exceeded the control by 0.4 % and the minimum by 1.0 %). The least soil moisture was formed in the variant with disking (15.9 %) with the onset of the phenological branching phase in chickpeas. The use of subsurface cultivation increased soil moisture by 0.9 %. Conclusions: combined tillage with a PBS-8M plow to a depth of 23–25 cm contributed to the formation of maximum chickpea yield in four years (1.04 t per ha, which is only 4 % more than the control). Minimization of the primary tillage to 10–12 cm reduced yield by 18 %, subsurface deep loosening (30–32 cm) by 9 % compared with the moldboard cultivation to a depth of 23–25 cm.