Changes of agricultural land characteristics as a result of afforestation using introduced tree species

The paper documents the mid-term changes of the soil characteristics and upper soil dynamics in the stands of introduced tree species, grand fir and Douglas-fir, on the former agricultural lands. These species were compared with Norway spruce stand and original grassland in the same site conditions at the Hruba Skala locality (Eastern Bohemia). The plot was established in 1980 on Luvisol type of soil, sandy clay. Altitude ranges between 350 and 360 m a.s.l., mean annual temperature was 7.8 °C, mean annual precipitation 703 mm. Results confirmed the starting process of the development of humus forms typical for forest ecosystems, despite the initial stage was dominant. The amount of surface humus (holorganic horizons) did not differ between the tree species stands and the agricultural land, but the grassland humus layer contained much more mineral particles. The grand fir was confirmed as a species favourably affecting the site, Douglas-fir affecting it less favourably in the given conditions compared with Norway spruce. Different dynamics was documented for soil reaction, characteristics of soil adsorption complex, soil acidity and nutrient dynamics.