Environment Regulations and the Impact on the Management of Dairy Farmers in the Netherlands

In the European Union nutrient management is a topic of major political interest.The goal for nitrogen (N) is that groundwater should contain less than 50 mg nitrate/l. The general approach might result in a maximum amount of N or number of cattle allowed per ha. However, individual countries develop alternative routes and take additional measures to deal with nutrient losses. The odour of manure as part of the environment is not a main theme in the discussions. In The Netherlands emphasis is placed both on phosphorus (P) and on nitrogen. In addition to the European guideline for nitrate, ammonia volatilization (emission) should be reduced by 50-70% in the year of2000 compared with 1980. Regulations limit the amount of manure (expressed in P) applied per ha. For some years a manure (P) quotum is allocated to each farm. A more balanced P-supply to the land is achieved by transport of manure from surplus to deficit area's. Also lower P-contents of the concentrate feeds are stimulated. N-losses can mainly be reduced by adapting the farm operation. Several management practices were studied with the PR-dairy-farm-model to assess their contribution to the mineral losses. A combination of a more efficient use of fertilizer N, restricted grazing in combination with a more balanced ration, and to a less extent, a higher milk production/cow resulted in considerable reductions in nitrate leaching. Application of slurry by injection techniques diminishes the ammonia volatilization at farm-level by almost 50%. Other low emission techniques, such as low emission housing and covering of slurry storages, have relatively a high cost. In practice, slurry application by injection has become obligatory. Injection has as side effect, that the smell of manure is largely eliminated from the environment. Application of manure to the land is only allowed in the growing seasons. Form 1998 farmers with a higher stocking (2,5 dairycowunit) rate have to keep a nutrient balance sheet. On basis of the nutrient balance a tax will be imposed on surplusses of N and P.