Structural-Aggregate Composition and Soil Water Resistance Based on Tillage Regimes in Southeast Kazakhstan

Abstract

The promotion and rational development of drylands employed two tillage regimes (plowing to 20–22 cm and no-till) during the spring wheat and barley cultivation in Southeast Kazakhstan. The results established that the no-till scheme contributed to forming an excellent aggregate state of the arable soil layer for spring wheat and barley (65%–69%). The water-resistant aggregates were the highest with no-tillage (19.3%–21.8%), indicating the unsatisfactory water resistance of the soil structure. Enhancing the water-resistant aggregates requires using organic fertilizers to improve the establishment of perennial grasses, green manuring, and cover crops. No-till system inclined to boost the optimal soil density from a loose and slightly compact state of 1.19–1.23 g/cm3 to a dense 1.32–1.39 g/cm3. According to crop cultivar and tillage methods, the spring wheat and barley grain yield varied between 2.84 and 3.89 t/ha. High grain yield came from the spring barley cultivar Symbat. Spring showed promising performance when the plowing level was 20–22 cm and inferior only by 0.25 and 0.15 t/ha with no-till. Based on the two-factor analysis of variance, the cultivar contribution to the spring wheat and barley grain yield buildup depended on the shares of crop season of the research (year – environment) (40.9%–62.2%) and the tillage regimes (22.4%–32.2%). The grain yield formation was more dependent on the studied crops and their cultivars, and the dependence increased over the crop seasons due to weather conditions during the crop period.

Soil Cultivation Methods’ Impact on Soil Water-Physical Properties Under Rainfed Conditions of Southeast Kazakhstan

“…According to the annual precipitation, absolute height above sea level, and the amount of total radiation in Southeast Kazakhstan conditions, it is customary to divide rainfed areas based on yearly rains into three categories, i.e., unsecured (200 to 280 mm), semi-secured (from 280 to 400 mm), and secured (over 400 mm) areas. Similarly, the maximum area share falls under unsecured rainfed land (64%), while semi-secured and secured rainfed lands occupy 26% and 10%, respectively (Zhapayev et al, 2023a). In this regard, there is a need to study various methods of soil cultivation.…”