Geomechanical and hydrological surface deformation caused by the underground hard coal extraction leads to limited agricultural and natural soil use. The paper presents results of soil productivity indices determined in the area of post-mining subsidence depression near Libiąż. The algorithm of method suggested by Zhengi Hu et al.  was used for the computations. The obtained results of field and laboratory analyses indicate soils degradation due to water logging and a necessity to undertake reclamation measures to restore their previous values. Determined productivity indices (PI) characterise the selected ground as the area with poor conditions for agricultural production. The reason for low PI values is a change in the soil properties because of degradation. The methods presented in the paper may be used to determine the degree of soil degradation in the areas of hard coal mining.