Научный журнал Российского НИИ проблем мелиорации (Aug 2019)
AGRO-PHYSICAL DEGRADATION OF IRRIGATED SYRT DARK-CHESTNUT SOILS OF SARATOV TRANSVOLGA REGION
Abstract
The aim of the research was to study changes in the agrophysical properties of dark chestnut soils as a result of long-term irrigation. The research was carried out at the Ershovskaya Experimental Station of irrigated agriculture of Research Institute of Agriculture of the South-East in Saratov Region in 1973–2010. Soils are syrt dark chestnut. The irrigation water is from the Volgograd reservoir, favorable for hydrocarbonate-calcium chemistry with a salinity of 0.2–0.3 g/dm³. Selection and analysis of soil samples were carried out according to standard methods. As a result of research, it was found that the long-term intensive irrigation of heavy loams granulometric texture syrt dark chestnut soils of dry steppe TransVolga region without special reclamation measures leads to agrophysical degradation of these soils. At the same time, the main signs of agrophysical degradation were identified: negative changes of granulometric and microaggregate composition of arable and subsoil layers of irrigated soils (the ratio of the finest clay particles increases significantly); the deterioration of the macroaggregate composition of the upper horizons of irrigated soil, the cloddy particles ration in its arable horizon increases by 39.2 %, in the subsurface – by 16.4 %; an increase in the bulk density of top layers of irrigated soil in comparison with the dry land from 1.03–1.07 to 1.17–1.39 g/cm³; a decrease of total porosity on irrigation to 48–56 % as compared with the dry farming land (60 %); an increase in the micropore ratio containing moisture inaccessible to plants from 24.1–27.3 to 32.5–48.0 % of soil volume while reducing the ratio of capillary pore (from 1.9–13.1 to 0.7–3.2 %) and aeration pore (from 3.9–10.0 to 1.1–2.8 %).
Keywords
