The results of research on the development of less water-intensive rice irrigation technology with periodic irrigation, allowing to reduce the cost of irrigation water in 3-5 times are presented. This irrigation technology solves a number of environmental problems associated with the formation of water deficit in the sources of irrigation, the water table rise, salinization, waterlogging, acidification and utilization of polluted waste and drainage water. During the development of water-saving technologies of rice irrigation special attention is paid to the development of high crops and systems of plant protection from weeds. The article provides recommendations for maintaining a less intensive water regime of soil with a humidity not lower than 80% HB from sowing to the end of the tillering stage in a layer of 0.4 m with a subsequent increase to 0.6 m, from wax to full ripeness of grain not lower than 70% HB. The combination of such water regime with fertilizer rate N109P62K75 provides a rice yield of 5.0 t/ha, a rate of N131P74K90 – 6.0 t/ha and a rate of N157P90K108 – 7.0 t/ha.

The article is devoted to using wastewater of the Orenburg Gas Chemical Complex in the amount of up to 7.0 million m3 for irrigating agricultural crops with the purpose of additional cleaning of wastewater and increasing the yield of agricultural crops. Analyzing the obtained data, it is shown that in the arid climate with rainfall deficiency, the use of wastewater for irrigation of forage crops is the best variant in providing the necessary measures for preserving the ecological status of the agricultural sewage farms (ASF). As a result of own research over years 1982 – 2015, the influence on the ecological state of ASF soils was detected in the form of deterioration of the water-physical properties and increased content of easily soluble salts in the soil; with that, the content of gross and mobile forms of heavy metals is significantly lower than MPC, but slightly above the background values, which does not affect the quality of sorghum harvest. Pollutants accumulate in the top layer of soil; therefore, the impact on surface water bodies has not been established. The authors suppose that maintaining the ecological state of ASF requires some measures like the introduction of calcium-containing substances and optimization of the irrigation conditions. The practical importance of scientific research is that based on the obtained results, a project of ASF soil rehabilitation has been developed and put into production.

Nowadays the water management measures are ineffective. The field trips of 2017-2018 are carried out. The Lower Volga is drained by 37 watercourses, 34 of them belong to small rivers. The right bank tributaries of the Volga are short and flow in deep channels - 76% of all tributaries of its lower reaches. Left bank waterways are long, flowing in shallow channels - 24%. This is due to the location of the right bank of the Volga within the Volga Upland with a developed ravine-net system and a zone of dry steppes. The left bank of the lower reaches of the Volga River lies in the semi-desert zone, where the ravine-gully network is poorly developed. Factors affecting the state of these rivers: the flow of wastewater from industrial enterprises; pollution by fertilizers, pesticides; flow regulation; irrevocable withdrawal of river runoff for household, industrial, agricultural needs. Measures to address these problems: the transition to modern water-saving technologies; cleaning of domestic, agricultural and industrial waste; toughening control over compliance with the norms of discharge of pollutants into rivers; the establishment of water protection and sanitary zones for all reservoirs; clearing channels, coasts and floodplains from debris; tight control over livestock grazing in floodplains; planting forest belts along the river channels.

Landscapes in the southern part of the Privolzhsky Upland represent a complex ecological system, functioning in severe geomorphological and climatic conditions. The study of erosion degradation and zoning of the southern part of the Privolzhsky Upland, limited by the interfluve of the Volga and Ilovlya rivers, with a total area of 1,156 thousand hectares, where the dissection of the gully and ravine network is 0.4–1.0 km·km–2, reaching in some places 3.5 km·km–2 was carried out by the methods of the joint analysis of digital elevation model, large-scale topographic cartographic basis and satellite images of the studied territory, using specialized programs and geographic information systems “Surfer” and “QGIS”, using the developed equation (S = 240exp(–(H–98.6)2/(–2,798.4)) + 2.16), which provides a simulation in landscape analogues. Studies provide an opportunity to identify the quantitative parameters of the landscape for each of the selected contours, to determine the most vulnerable areas to erosion, which will allow us to develop a plan of work to prevent the washing away of the fertile soil layer using the example of our modelling.