Effect of controlled liming on the soil chemistry on the immission clear-cut

Results obtained during 14 years of the experiment are presented. Extreme site conditions are determined by: 8th vegetation altitudinal zone, podzolic soil and hard climate - average annual temperature 4°C, average annual precipitation around 1,200 mm. Effects of surface experimental liming were studied on immission clear-cuts in long time period, study area is located on the Velká Deštná locality on the main Orlické hory Mts. range. Research plots were established and the basic survey was done in spring of 1988, studies of liming effects were performed in the period 1987-2002. On particular plots, 0, 1,308, 2,826, 3,924 and 8,478 kg/ha of fine limestone (grain size under 1 mm) was distributed by hands on the soil surface, as an application of 3 and 9 t/ha of "fine" and "coarse" material (together 5 variants including the control one). Results are available for the forestry practice, research has to continue in the future - potential of negative liming impacts is topical here, consisting in humus mineralization and nutrients losses. Maximum effects on the soil reaction were observed in 8-10 years after limestone application at the soil surface (F - horizon) and in the period 10-15 years lower (H, A - horizons). Base saturation dynamics shows the time delay 2-4 years following pH values. For the site protection, efficient forest stands are vitally important of pioneer as well as climax species.