The article shows the results of long-term studies aimed at assessing the formation of ameliorative regime of natural-anthropogenic complexes in Kalmykia. Initial parameters have been presented for models of forming the water-salt regime of the irrigated agricultural landscapes with their comprehensive amelioration in semi-desert and desert areas of Kalmykia. The influence of water-salt regime of soils on the productivity of saltmarsh bluegrass and alfalfa has been studied, and the threshold of salt tolerance for these crops has been defined. The technology of recovering re-salinized irrigated land with the use of reclaimer crops has been developed, which makes it possible not only to rehabilitate the soils that are adverse due to re-salinization, but to obtain extra quality forage as well.

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In 1995-2015, in the dry steppe and semi-desert zones of the Caspian lowland, a series of experimental studies were conducted on brown and light chestnut soils to establish the total evapotranspiration of annual fodder crops using irrigated arable land. Four different methods were studied; the water balance method was used as a control one. The temperature coefficients of the total water consumption, as well as the coefficients of an air humidity deficit combined with the scale of biological time of vegetation were determined. Specified coefficients of water consumption were determined; they were differentiated depending on different conditions of mineral nutrition and the planned yield. For production conditions, biological and mathematical models of dependence have been developed in order to determine an optimal water regime in the arid zone. Based on the obtained experimental data, the convergence of the calculated values obtained by the bioclimatic and water balance methods was achieved. The planned crop yield was produced.

The experiment is carried out in the conditions of semi-desert flat agricultural landscapes of light chestnut soils. The object of research is a 4-field crop rotation (factor A), variants of the main tillage (factor B) and crops superimposed on the tillage options with the Don-114 seeder (a seeder for direct sowing). The placement of options (A) is sequential and options (B) are arranged in blocks in three tiers. The main soil tillage was carried out by the following tools: mouldboard tillage to the depth of 25-27 cm by plough PN-4-35; non-mouldboard tillage to the depth of 25-27 cm by the tool OCHO-5-40 with the rack “Rancho”; surface one to the depth of 8-10 cm by the tool BDM-4.2, and 4-field grain-fallow crop It was found that a higher content of nutrients is in fallow preferably at non-mouldboard soil treatment, in some years, which has an optimal moisture supply, and control (mouldboard) one in comparison with lower levels of surface soil treatment in all years of the research. The main comparison in the change in nutrients in fallow fields is observed precisely for different methods of soil cultivation.