Do mowing regimes affect plant and soil biological activity in the mountain meadows of Southern Poland?

Abstract

The soil biological activity of mountain meadows is a significant factor that determines the health and utility of these regions. The climax stage of this area is forest, but to maintain semi-natural grassland, which is characterised by high biodiversity, low-intensity land use (mowing or grazing) is necessarily required. To understand the effect of various mowing regimes on the soil biological activity and plants, the soil microbial activity (microbial biomass carbon, dehydrogenase activity and number of the cultivable fraction of soil microbial community), annelids community (density and species composition earthworms and enchytraeids) and plant species composition were investigated. The study area was located in the Pieniny National Park in the Carpathian Mountains, in a meadow belonging to the association Dactylis glomerata-Poa trivialis. The investigated variants were divided according to mowing regime: traditional scything - hand mowing (HM), mechanical mowing (MM), or the abandonment of mowing - non-mowing (NM). The microbial activities (expressed by, e.g. microbial biomass carbon and the number of phosphorus bacteria) were affected by the mowing regime. The density of earthworms was higher in the HM and MM than in the NM variants. The largest changes in plant species composition were caused by the abandonment of mowing (NM). The mean number of plant species was positively correlated with soil moisture, earthworm density, and microbial activity (expressed indirectly by dehydrogenases activity). The soil microbial community, such as vegetative bacteria forms and ammonifying bacteria, were positively associated with pH value, and the microbial and total organic carbon content. The results presented here indicate that there is no single form of optimal management for all living organisms. Decisions about mowing regimes, or abandonment of use, should be preceded by multi-aspect studies, including plants and soil biota.