44 National phosphate balance Phosphate enters the Netherlands by transboundary rivers (Rhine, Meuse and Scheldt) and the northern delta of the Ems, as rock phosphates, other organic and inorganic sources, and together with imported food and animal feed. Phosphate in transboundary rivers is also exported again and effectively discharged into the North Sea. Rock phosphates, fertilisers and other organic and inorganic sources (including phosphoric acid), food including waste, animal feed and manures are also partially exported. Although most (83.1%) of the phosphate entering the Netherlands leaves the country again, 183.2 Gg P2O5 (80 Gg P) – i.e. 16.9% of the annual input for 2005 – accumulated in the Netherlands (Table 6.1). Accumulated P is found in end products, residual P in (non) agricultural soils and in surface waters and sediments. Improving the national phosphate balance can be achieved by decreasing input and / or by increasing output. Table 6.1: National phosphate balance in the Netherlands in 2005 in Gg P2O5. Source: CBS StatLine; June 2010, P2O5 = 2.29 x P. Input Transboundary rivers (In)organic compounds Food Animal feed Total input 22.9 748.8 169.5 142.0 1083.2 22.9 648.1 185.5 43.5 900.0 57.3 77.9 38.9 9.2 183.2 Output Transboundary rivers (In)organic compounds Food including waste Animal feed and manures Total output Accumulated Final products Agricultural soils and ground water Non agricultural soils and groundwater Surface water and sediments Total accumulated It is assumed that all phosphates imported in transboundary rivers are also exported again, so there is no net effect on the national P balance. The Netherlands cannot control the transportation of P in transboundary rivers; control requires coordinated multinational decisions taken by the countries along the Rhine, Meuse, and Scheldt river basins and the Ems delta. All four river basins are densely populated (100–450 inhabitants per km2), industrialized and have intensively managed agriculture (Oenema et al., 2005). The countries in which these river basins are located must jointly implement effective measures to decrease phosphate loading into these river basins. Food production in the Netherlands exceeds food import, so net phosphate export in food exceeds net phosphate import. Feed export levels are small compared with import levels, so much of the phosphate P in feed remains in the country. The P balance of feedstock is an essential part of the total agricultural phosphate Pagina 53

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