Influence of meteorological conditions on water balance of soils created from post-mining grounds

The paper presents results of field research and observations carried out in the hydrological years 1992/ 93 to 1997/ 98 in the inner waste heap of the "Patnow" open pit, situated in the Kujawskie Lake District (52degrees20' N, 18degrees14' E). Field research and observations were conducted in 3 experimental plots undergoing agricultural land reclamation, with differing agricultural uses and uniform mineral fertilisation. The research results indicate that upper layers of agriculturally reclaimed soils in post-mining areas are characterised by differences in gain composition and physical and hydrological properties, which significantly affects water balances in the soils of the area, However, the dominant factor influencing water balances in post-mining soils is the type of weather conditions in terms of levels of precipitation and evapotranspiration. They have a decisive effect on water balance in the soils of the area. During vegetation periods which are numbered to wet ones (1997) as regards precipitation, there is a significant participation of outflow in the water balance of one meter layer of post-mining soils. Detailed analysis of water balances in of upper soil layers made of post-mining soils also revealed that unfavourable distribution of precipitation and course of air temperatures caused, that even during wet vegetation period 1997 (when taking into consideration precipitation), upper soil layers showed periodic deficit of moisture. Also during this period the longest periods of water deficit occured in soils with small retention abilities.