Influence of irrigation methods on agrophysical properties and productivity of dark chestnut soils of dry steppe on the left bank of the Volga river

The article presents the results of the studies concerning the influence of irrigation methods on agrophysical properties and productivity of irrigated medium loamy dark chestnut soil of dry steppe on the left bank of the Volga river. It is proved that the use of surface irrigation by strip flooding leads to the most unfavorable changes in the agrophysical state of the upper layers of the studied soil difference in comparison with the use of surface irrigation along furrows and sprinkling via wide-grip sprinklers. With strip irrigation the total porosity of the arable and subsurface soil horizons decreases to the greatest extent in comparison with furrows and sprinkling, the proportion of the most agronomically valuable meso-aggregates in the soil structure decreases, while the proportion of small silty micro-aggregates and large macro-aggregates increases to the maximum. All this determines the lowest productivity of irrigated dark chestnut soil after irrigation in strips, as compared to sprinkling and furrow irrigation (spring wheat yield decrease makes 0.55 t/ha and 0.77 t/ha, respectively).