РОЛЬ СЕВООБОРОТОВ В ПОДДЕРЖАНИИ АГРОФИЗИЧЕСКИХ СВОЙСТВ ЧЕРНОЗЕМОВ, ОРОШАЕМЫХ СЛАБОМИНЕРАЛИЗОВАННОЙ ВОДОЙ

Abstract

Purpose: to determine effects of grain-fodder and vegetable crop rotation on the agrophysical properties of chernozems irrigated with low-mineralized water, in comparison with the non-irrigated counterpart. Materials and methods. The studies were carried out in Neklinovsky district Rostov region on ordinary chernozems in grain-fodder crop rotations, non-irrigated (without irrigation) and irrigated with annual irrigation rates of 1500–2500 cubic m/ha and in vegetable crop rotation with annual irrigation rates of 3000–4000 cubic m/ha. The source of irrigation is the Miussky estuary with low-mineralized water. Soil samples were taken in autumn after crop rotations, their granulometric texture, aggregate water stability and humus were determined. In profile pits - the soil bulk density. The selection of soil samples, their analysis and evaluation were carried out according to generally accepted methods. Results. The deterioration of water-physical properties was most clearly manifested during long-term irrigation with low-mineralized water on a plot with vegetable crop rotations, where irrigation rates were more than 3500 cubic m/ha. The arable land of such chernozem is highly compacted (1.41 t/cubic m), the bulk density 40 cm deeper is 1.45–1.47 t/cubic m. By granulometric texture, the upper soil layers acquired the properties of medium loamy soils due to the leaching of clay particles. There are practically no water-stable aggregates along the soil profile (about 10 %). Soil porosity deteriorated to excessively low values. Conclusions. Studies have shown that the higher the water load in crop rotations, the more the negative agrophysical properties of chernozems progress, especially when irrigated with low-mineralized waters.