DERIVATION OF SOIL-WATER CAPACITY PARAMETERS FROM STANDARD SOIL TEXTURE INFORMATION FOR BULGARIAN SOILS

Prediction of total porosity and volumetric water content at field cap acity, and permanent wilting point have been evaluated for their possi ble applicability to supply important missing soil information. The re sults were compared to the experimental data from Bulgaria. Also the p ossibility is explored to convert soil particle size distribution data as determined according to the soil standards in Bulgaria to the foll owing particle size fractions ('sand' (0.05-2.0 mm in diameter), 'silt ' (0.002-0.05 mm) and 'clay' (smaller than 0.002 mm)). The approach te sted for calculating total porosity and volumetric water content at fi eld capacity, and permanent wilting point yielded values in close agre ement with the measured ones.