Nitrogen (N) management in the 'De Marke' dairy farming system

摘要: In the sandy regions of The Netherlands, high losses N from intensified dairy farms are threatening environment. Therefore, government defined decreasing maximum levy-free surplusses for period 1998–2008. On most farms, current surplus has to be reduced by half at least. Farmers fear that realizing these will expensive, because it limits application animal manure, which then exported or additional land bought. Moreover, farmers worried about impact on soil fertility. To explore possibilities reducing average intensive improved nutrient management, farming systems research is carried out prototype farm ‘De Marke’. Results compared with results a commercial in mid-1980s, moment started and introduction milk quota system put halt further intensification. indicate can realise reduction level below final maximum, without need buy export slurry. Inputs purchased feeds fertilisers decreased 56 78%, respectively. Important factors feed intake per unit milk, as result higher yield cow, less young stock judicious feeding, an utilization ‘home-made’ manure considered balance between grassland maize area. Changed fertility status did not constrain crop production. Nitrate concentration upper groundwater 200 50 mg l-1, within few years.