Nitrate Sensitive Areas: a study of large scale control of nitrate loss inEngland

The pilot Nitrate Sensitive Areas Scheme was set up in England in 1990 to t est measures aimed at reducing nitrate losses from agricultural land. Ten g roundwater catchments were chosen to typify the geology and farming of area s where nitrate concentrations in abstracted water were high. Voluntary and compensated controls on farming, based on recent research, were introduced . Scheme membership was for 5 years from 1990 or 1991, and 86% of the agric ultural land entered the Scheme. On all farms entering the Scheme, manure a nd fertilizer use were restricted and green cover crops were required over winter (Basic Scheme). Additional payments were available for conversion of arable land to zero or low-input grassland (Premium Scheme). Intensive pig and poultry farmers were assisted with the costs of transporting manure fo r spreading over a wider area. The most effective changes were improved man agement of livestock manures, especially of the very large local quantities from housed pig or poultry units; conversion of arable land to low-input g rassland; and use of cover crops. There were no indications of reduced crop yields but some requirements increased costs and management complexities. Estimates based on both model calculations and measurements indicated that nitrate losses from agricultural land decreased by about 30%, with consider able variation between areas.