The effects of agricultural management on the soil biota of some upland grasslands

Intensification of sheep farming in the uplands has caused concern in terms of over-production and conservation of wildlife and landscape. Changes in UK agricultural policy to combat these problems are likely to result in reduced pasture improvement and sheep grazing in the uplands. This paper examines the effects, on three adjacent uplands grasslands, of different intensities of sheep management on the soil biota. The effects of short-term removal of sheep grazing by fenced exclosure were also studied. After preliminary investigations the soil Collembola, in particular the fungal-feeding species Onychiurus procampatus, were selected for further study. Field sampling revealed simultaneous trends of decreasing Collembola numbers and increasing total hyphal length and biomass of fungi in the surface soil, together with differences in chemical and physical soil properties, along a gradient of reduced sheep management intensity. Similar changes occurred when sheep grazing was removed by fenced exclosures. The abundance of fluorescein diacetate-active hyphae within the surface soil was shown to vary little along the same gradient of reduced sheep management intensity. The relative abundance of the seven most commonly isolated species of litter fungi varied along the same gradient of sheep management. The findings are discussed in relation to other grassland studies.