On evaluating the effectiveness of the soil water management in the forest-steppe and steppe zones

The Paper pesented is the generalize estimates of the effectiveness of the human activity in an effort to reduce the intensity and recurrence of droughts. The "dry agriculture" technique such as retention of the meltwater in the fields, autumn ploughing, fallow and surface soil mulching with crop residues is under investigation. The evapotranspiration model with standard meteorological data and leaf area index is used to obtain the agricultural field water supply under natural water supply conditions and "dry agriculture" technique. The agricultural field water supply was analyzed for large scale spatial trends over many years for the spring wheat fields represented by 45 agrometeorological stations in the forest-steppe and steppe zones of the Former Soviet Union. For 6 agrometeorological stations the agricultural field water supply for individual years within a period over 20 years was examined. A comparison between the agricultural field water supply under natural water supply condition and "dry agriculture" technique has been carried out. The calculation showed a rather low natural agricultural field water supply in the forest-steppe and steppe zones. Retention of the meltwater in the fields, autumn ploughing and fallow tends to increase the agricultural field water supply by 10 to 20%. The surface mulching tends to increase the agricultural field water supply by about 1.7 times.