Soil Water Retention Curve: Experimental and Pedotransfer Data to Forecast Water Movement in Soils

Soil water retention curve (WRC) - the most important hydrological characteristics of soils, which determines the movement of moisture and soluble substances in soils. This relationship between soil moisture and capillary pressure of moisture, is included in all forecasting mathematical models of moisture movement in the soils. To assess the adequacy of model calculations with using the WRC, obtained by different methods, WRC was defined by experimental laboratory methods, or was calculated by using pedotransfer functions (PTF). Then the calculated data and field nature experiments on the movement of moisture were compared with. The precision of moisture movement modeling in the soil was significantly determined by the method of obtaining WRC. The results of the experimental modeling of soils water regime, significantly the results of the simulation were located in the following descending order of precision: regional PTF > WRC (water retention curve), obtained by the method of sand-kaolin boxes > WRC, obtained using capillarimeters > PTF used in the program Agrotool (on the basis of the experimentally obtained hydrological constants) > PTF using as predictor of granulometric structure (from the data base ROSETTA) > WRC obtained using the centrifuge method > PTF based on Voronin‘s «secants». It is recommended to create regional hydrophysical data base to calculate pedotransfer functions for forecasting modeling of soil water movement.