Bohner


Die Bodenkultur - Journal for Land Management, Food and Environment

A. Bohner, R. Öhlinger und O. Tomanova:

Effects of grassland management and abandonment on vegetation, soil, microbial biomass and forage quality

Summary

A species-rich permanent meadow (Cardaminopsido halleri-Trisetetum flavescentis) with two cuts every year on a relatively nutrient-poor soil and an adjacent abandoned meadow, dominated by grasses, was investigated comparatively. The abandoned meadow was afforested with only few spruce trees (4 trees within 50 m2) and the adjacent permanent meadow was moderately fertilized with slurry. Abandonment caused within 7 years a reduction in vascular plant species richness, a decline in flowering plants, a change in plant species composition with increases in rhizomatous species, shade-tolerant species and species with low tolerance of frequent defoliation, an expansion of Festuca rubra ssp. rubra, an increase in cover value of the moss layer, a change in life forms, an increase in below-ground phytomass, an increase in root:shoot-ratio, a deeper and more uniform root distribution in the soil, a slight increase in above-ground phytomass at the time of first cut in the meadow, a reduced forage quality, and an accumulation of individual nutrients in the above-ground phytomass. In topsoil the following changes of soil chemical and microbial properties after abandonment were established: accumulation of nitrogen-poor humus, increase in C:N-ratio, slight increase in exchangeable acidity, increase in magnesium content due to bioaccumulation, and decrease in microbial biomass. Some soil physical properties were influenced positively: aggregate stability increased slightly and, because of the absence of mechanical compression by human influence, there was no soil compaction resulting in stagnant water conditions in topsoil. This later feature is typical for intensively managed grassland soils. Abandoned grasslands fulfil a sink function for atmospheric CO2, because of the gradual accumulation of nitrogen-poor humus. In addition, there is an increase in nitrogen-retention capacity of the topsoil. A low nitrogen- and potassium availability in the soil favours in early successional stage the development of Festuca rubra ssp. rubra dominated abandoned grassland on acid, deep, well-drained soils in the montane belt. This kind of abandoned grassland does not get lost immediately as agricultural area because of the inhibited growth of trees and shrubs. Abandoned meadows, dominated by grasses, are not very important for the floristic species protection and landscape aesthetics in mountainous regions.

Key words: Abandoned meadow; permanent meadow; plant community; plant species richness; life forms; aboveground and below-ground phytomass; forage quality; soil physical, chemical, and microbial properties.