There is a conflict in British grassland farming between management for agricultural purposes, centring on profit maximisation, and that of nature conservation and the enhancement of biological diversity. Within the European Union's Common Agricultural Policy there is a growing emphasis on reducing output from the community's livestock sector and this is achieved through allocation of quotas (sheep and milk) whilst maintaining alongterm agricultural base. This could result in the widespread adoption of more extensive grazing regimes. An experiment was set up in upland Wales in 1991 to study the effect of reducing inputs and defoliation on species balance and animal production in a Lolium/Agrostis dominant pasture. Spectacular changes in species balance took place in the first grazing season. Elimination of CaPK and N applications encouraged Agrostis capillaris at the expense of Lolium perenne and Poa spp. and led to a 43% reduction in stock carrying capacity by the 3rd year. Where no defoliation took place important pasture species such as Lolium perenne and Trifolium repens were lost from the swards-by-theZ&year:However;-an-annu&midsummer cut maintained these potentially highly productive species within the sward. Keywords: extensive grazing, low inputs, ryegrass, sheep, species balance, Trifolium repens, upland Britain
