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. C hanges in UK agricultural policy to combat these problems are likely t o result in reduced pasture improvement and sheep grazing in the uplan ds. This paper examines the effects, on three adjacent upland grasslan ds, of different intensities of sheep management on the soil biota. Th e effects of short-term removal of sheep grazing by fenced exclosure w ere also studied. After preliminary investigations the soil Collembola , in particular the fungal-feeding species Onychiurus procampalus, wer e selected for further study. Field sampling revealed simultaneous tre nds of decreasing Collembola numbers and increasing total hyphal lengt h 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 grazin g was removed by fenced exclosures. The abundance of fluorescein diace tate-active hyphae within the surface soil was shown to vary little al ong the same gradient of reduced sheep management intensity. The relat ive abundance of the seven most commonly isolated species of litter fu ngi varied along the same gradient of sheep management. The findings a re discussed in relation to other grassland studies.