Under consideration are results of studying an actual and very important problem related to dangerous underground flood processes and their occurrence in southern regions of European Russia. A comprehensive analysis was made to identify reasons for the development and intensity of such processes. It is shown that the underground flood processes become more intensive due to human activities in the sphere of water-power engineering. A system of measures is proposed how to protect the lands from the underground flood represented by a complex of preventive measures to maintain the optimal water-air regime in soils and to remediate their productivity.

Original methodology for land evaluation was elaborated as based on GIS technologies and FAO land evaluation approaches. Unique register of soil resources of Russia was used as a basis for land suitability analysis for hop cultivation in Russia. Optimal territories for hop cultivation occupy in Russia only 0.01% of lands. Greatest constraints for hop cultivation are associated with the soil and climatic conditions. The smallest potential expenditures for the cultivation of hop are expected for the territory of European Russia, the south of West Siberia and in the Far East on the “warm” plains. The greatest investments will be required for the cultivation of hop in the mountain regions of the Urals, Altai, in the mountains of East Siberia and Far East.

Under consideration is the influence of climate changes (the air temperature rise in the cold 6 months especially in the winter and the increased atmospheric moistening in the warm 6 months) on regimes and properties of soils in dependence on zonal-provincial, geomorphological and lithological conditions as exemplified by the solonetz complex in the semi-desert Pre-Caspian plain and chernozems in central European Russia and southern regions of this country.

The paper is devoted to the analysis and evaluation of peculiar features of the water regime in loam-sandy soils of Oman. The total water volume taken up by potatoes has been determined in different modes of pre-irrigation soil moisture (70, 80% of MWC and 70-80-70% of MWC) and in dependence on the water-holding layer consisting of natural materials. It is shown that the most favorable conditions for water supply of potatoes, taking into account the economical use of irrigation water, can be created by differentiation of pre-irrigation soil moisture in inter-phase periods at a level of 70-80-70% of minimum water capacity (MWC). At the same time, sapropel should be used as a water-holding layer, which increases the potatoes yield at least by 10%.

The intensity of soil-biological processes reveals changes in different-sized aggregates of post-agrogenic migrational-mycellary chernozems. Transformation of the organic matter and its decomposition by microorganisms in particular becomes more active in fine aggregates (<1 mm), the microflora activity in the carbon cycle increases in aggregates from fine to coarse ones. The activity of microorgenisms in the nitrogen cycle shows increase from fine to agronomically valuable aggregates (1.0-5.0 mm) being further decreased towards coarse aggregates. In agronomically valuable aggregates the major soil-biological processes prove to be stable or the amount of microorganisms gets increased, that - is why they may be considered as biologically valuable ones.