Developments in mineral surpluses and water quality in the Dutch dairy sector, 1960-2010

This article shows developments in mineral surpluses and in water quality in the Dutch dairy sector in
relation to agricultural and environmental policy. In the 1960s and 1970s a major intensification of
animal production took place in the Netherlands due to an agricultural policy aimed at high productivity
and low prices. Nitrogen and phosphate soil surpluses on dairy farms increased up to 400 kg/ha and 82
kg/ha respectively in 1985. This development resulted in high nitrate levels in the groundwater and
loading of the soil with phosphate. From 1984 onwards, measures have been taken to tackle these
problems. From 1985 to 2010, this environmental policy realised a reduction on dairy farms of nitrogen
soil surpluses by 60% and of phosphate soil surpluses by 85%, while the milk production per ha

increased by about 12%. The reduction in mineral surpluses was realised by lowering the input from

nitrogen and phosphate in purchased fodder by 15 to 30% and the application of nitrogen and

phosphate by chemical fertilisers by 65 to 90%. On dairy farms in the Sand region, the average nitrate

concentrations in water leaving the root zone decreased from more than 150 mg/l (1992-1995) to 47
mg/l (2008-2011). Analysis of the relation between mineral surpluses and economic results shows that,
on average, dairy farmers with relative low surpluses of nitrogen and phosphate have relative high
economic results.

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