ИЗМЕНЧИВОСТЬ И ЭКОЛОГИЧЕСКОЕ СОСТОЯНИЕ РИСОВЫХ ПОЧВ РОСТОВСКОЙ ОБЛАСТИ (НА ПРИМЕРЕ РИСОВОЙ СИСТЕМЫ ООО «МАНЫЧ-АГРО»)

Abstract

Purpose: to study the soil properties in the rice system at Manych-Agro LLC, to determine their variability in the space of rice paddies and to assess the ecological state of soils. Materials and methods. On a representative plot, the groundwater table level (GWL), water-physical and physico-chemical properties of soils under different crops of rice crop rotation were studied. Soil samples in non-irrigated plots were also taken for comparative analysis (sunflower, winter wheat and alfalfa). Results. It was revealed that the soils in the arable layer of rice system of Manych-Agro LLC are characterized mainly by weak salinity, gypsum-bearing layers in depth. There is practically no alkalinity, but magnesium alkalinity prevails in the absence of sodium one and low content of exchangeable calcium in the soil absorbtion complex (SAC) in the 40-cm layer (from 60 to 72 % of the total SAC). The humus content is low to very low. The above mentioned negative properties of soils contribute to their strong compaction. Variability of soil properties indicators in space is different. The most significant soil variability was found in salinity (V = 103 %) and solonetzization of soils (V = 25...40 %), and insignificant – in exchangeable calcium (V = 10 %). Humus has an average variability (V = 16 %) for rice fields. Conclusions. The ecological state of soils is ambiguous. Exceeding the GWL, loss of humus and the increase in the proportion of magnesium in SAC characterize the situation as an ecological disaster, and an increase in soil compaction and a decrease in the amount of exchangeable calcium form an emergency situation. A relatively satisfactory situation is emerging in terms of soil salinity and exchangeable sodium.