Agricultural Waste Management: Nutrient Emissions from Agriculture in the Netherlands

Abstract Agriculture causes 60% of the total nitrogen emissions and 40~50% of the total P emissions to the surface waters in the Netherlands. These high emissions are mainly caused by the large amounts of fertilisers used on Dutch farms. On average, 39kg P/ha and 340kg N/ha are given in excess to the uptake by the crop. The Netherlands follows a strategy of gradual reduction of the nutrient applications to crops. The first two phases were aimed at stabilisation and a gradual reduction of the use of organic manure. The goal of the third phase is to accomplish equilibrium fertilisation in the year 2000. This means that the amount of fertiliser given may not exceed the crop uptake, considering an acceptable loss to the environment. The losses are based upon acceptable emissions, mainly to surface waters. With the average excess rainfall in the Netherlands, the water quality standards are met with a loss of 0.4kg P/ha and 6kg N/ha, much lower than the present excesses of minerals. The challenge for the future is to close the gap between environmentally acceptable and present losses. Equilibrium fertilisation will not solve all problems at short notice. Therefore, additional techniques to reduce nutrient losses are in development. Examples are restoration of buffer strips and wetlands, lowering of groundwater levels, dosing of ferric and aluminium compounds in the soils and several additional measures in eutrophied lakes.