The role of snow retention in regulating water balance and productivity of spring wheat in biologized crop rotations in the rainfed zone of Akmola region

Abstract

Background and Aim. Akmola region is an arid region, where the annual precipitation averages 320-360 mm, a significant part of which falls as snow. However, snow cover height accumulated due to stubble remaining after grain crops (typically, 15-20 cm is often blown away into shelterbelts and does not contribute to grain crop yield. The purpose of this research was to study the effect of snow retention on the soil water regime and the yield of spring wheat within a biologized short-rotation crop sequence that includes a green manure fallow.

Materials and Methods. Over three years, observations were made regarding snow accumulation, background moisture supply, and spring wheat yield following a green manure fallow planted with a pea-oat mixture. The qualitative indicators of the snow cover (height, density and water reserve) were determined concurrently. After the snow melted and prior to sowing wheat, and again before harvest, the reserves of productive moisture in the top one meter soil layer were measured. At the end of the growing season, the wheat grain yield was recorded.

Results. In plots where wheat was sown as the first crop following the green manure fallow, the best soil water physical properties and crop productivity were noted in the variant utilizing snow retention. In this variant, snow depth was 37.3 cm, water reserves in the snowpack were 115.7 mm, and productive soil moisture reserves were 122.4 mm. In plots where wheat was sown as the fourth crop in the rotation following the green manure fallow, the best indicators were also achieved with snow retention techniques: snow depth was 52.8 cm, water reserves in the snow were 132.0 cm, and productive soil moisture reserves were 124.2 mm. Furthermore, the lowest soil density was recorded in this variant ( 1.21 g/cm3 and 1.18 g/cm3 on the first and second backgrounds, respectively). The highest spring wheat grain yield in the variants using snow retention was 18.4 c/ha and 14.5 c/ha on the first and second backgrounds, respectively.

Conclusion. Despite the dry climatic conditions during the study years, the implementation of the snow retention positively affected both moisture accumulation in the soil and the final wheat yield.