ZLV Online

Experimental catchment „U Vodárny“ in the area of the Hrubý Jeseník Mts. was established in 1988 with the aim to investigate precipitation and run-off relationship in forest stands as well as chemistry of soil profile. Samples were taken according to genetic horizons in years 1991, 1999 and 2005. In 1992 the stand was limed by dolomitic limestone. Due to decrease of pollutant fallout dynamics of particular elements was found to be different depending on elevation of individual partial plots. Also saturation degree of sorption complex was developing differently in various profiles of individual plots in dependence on tree species composition of stands formed mainly by spruce and partly by beech. Total content of Ca, K and Mg increased only in profile of forest floor whereas in rhizosphere, above all in surface horizons of mineral soil supply of basic cations in sorption complex decreased since 1991 even when the fallout of acid substances was reduced. Probably it is caused by their consumption by stands roots supported by enhanced fallout of nitrogen and proton buffering of protons arisen during nitrification of ammonal ions and because nitrogen compounds are accepted from atmospheric fallout by roots. For preservation of production abilities of soil it is of importance that on investigated plots pH/H2O does not fall on values lower than 4.2, when destruction of clay minerals occurs but on the contrary their creation can be supposed in deeper horizons of plots with pH/H2O > 5, where primary minerals are weathering.