Comparing long-term effects on soils from four different catchment experiments in a coniferous forest around Lake Gårdsjön, SW Sweden

Sammanfattning

When acidification of soils and lakes got acknowledged in the 1960’s, it soon became one of the biggest environmental issues in northern Europe. Long-range transport of sulphur and nitrogen emissions caused acid rain to fall thousands of kilometers away from its source. South-western Sweden was one of the areas most affected by acidification. One of the lakes affected is Lake Gårdsjön, situated about 15 km from the west coast of Sweden in Ucklum municipality. Here, research about acidification has taken place since the 1970’s. Here, data from 1990 and 2016 are used to evaluate long-term effects on soils from different catchment experiments such as liming of soil, sulphur fertilization, exclusion of acidic deposition, and nitrogen fertilization (NH4NO3). The effect from the experiments on two indicators of acidification (hydrogen ions [H+] and base saturation (BS)) were analyzed across the major soil horizons (O, A and B). The limed soil (F2) showed long-lasting effects with lowest [H+] and highest BS compared to the other catchments. The catchment with added elemental sulphur (F5) showed signs of long-lasting effect from acidification reflected in low BS. The exclusion of acidic deposition was not clearly reflected in [H+] or BS 15 years after treatment. The acidifying effects from nitrogen addition was indicated by having the highest [H+] in the mineral soil horizons. Results confirm a slow and non-linear recovery rate of acidified soils and varying lasting effects from treatments.