The goal of NSAs is to reduce leaching to groundwaters in areas where nitrate levels breach, or are likely to breach, the 50mg/l limit set by the 1980 EC Directive on drinking water. The schemes are voluntary and offer farmers compensation payments in exchange for changes in agricultural practice.
The latest proposals differ from the pilot scheme because they are targeted on small "inner zones", close to water supply boreholes, rather than wider catchments. The theory is that changes in agricultural practice in these areas will reduce nitrate levels in groundwater more rapidly and cheaply.
To achieve results over a relatively small area, MAFF's goal is to encourage farmers into a "premium" scheme where higher rates of compensation are available in exchange for greater restrictions on farming practices. The premium option had a poor uptake in the pilot NSAs, and the National Rivers Authority (NRA) was concerned that the new NSAs would not attract a sufficient uptake to be effective.
In August, MAFF announced details of the finalised scheme which show that major concessions have been made to make the scheme more attractive to farmers. The most significant concern the option which allows farmers to continue arable cropping with limited nitrogen inputs.
The arable option now allows organic manures as well as inorganic fertilisers to be used as part of the nitrogen quota. It also includes a new sub-option which allows farmers to apply nitrate fertilisers up to the crop requirement and grow "nitrate-leaky" crops, such as potatoes and brassicas, for one of the five years of the scheme.
The changes will be welcomed by the National Farmers Union, which argued that their inclusion would be financially attractive to farmers. However, there are fears that the measures may go too far and threaten the scheme by allowing higher levels of nitrate leaching.
The application of organic manures is known to increase nitrate leaching for several years after application. High levels of nitrate leaching also occur after harvesting of potato and brassica crops.
The new scheme has been criticised by the Fertiliser Manufacturers Association (FMA) because it moves away from allowing application of fertilisers at the crop requirement to specifying an absolute limit of 150kg of nitrogen per hectare. The FMA says that experiments show there is no environmental advantage to limiting nitrate applications below the crop requirement and crop yields will be needlessly reduced.