36 5.2 Historical trends Administrative data on the consumption of phosphate in the Netherlands is only available for the period 1985 – 2008 (Figure 5.2), when phosphate consumption in the country declined substantially from 332 000 t P2O5 in 1985 to 177 000 t P2O5 in 2005. This reduction was largely driven by a decreasing consumption of inorganic phosphate commodities such as feed additives and detergents (> 50%) and phosphate fertiliser (> 40%). The decreasing overall trend is further accelerated due to the decreasing consumption of animal feed (Figure 5.1). The decreased consumption of inorganic phosphate (excluding phosphate fertilisers) - from 119 000 t P2O5 in 1985 to 50 000 t P2O5 in 2005 – was caused, at least in part, by a decreased consumption of feed additives. Substantially fewer feed additives were needed following the introduction of phytase in animal feed, which increases the uptake of phosphate from feed (Schoumans et al., 2008b). Next, standards for P requirement of animals were lowered. For instance for dairy cattle the guide line for the P content of grass was lowered from 4 to 3.5 g/kg dry matter. As a consequence, the need to import large quantities of animal feed also decreased (Figure 5.1). A reduction of phosphate in detergents to prevent eutrophication of surface waters could further explain the decreasing consumption of inorganic phosphate since 1985. Compared to 1985 industry and communities were able to lower P input in freshwater streams in 2000 with 75-89% while agriculture lowered only 12%. Figure 5.1: Historical trend of phosphate consumption in the Netherlands in the last century (total net consumption, net import of animal feed, net consumption of inorganic phosphate excluding fertilisers, and net consumption of fertilisers). Historical trend of the Dutch population shown in grey (Sources: CBS, 2001; CBS, 2009a). The consumption of phosphate fertilisers has been declining since it peaked just after the Second World War (Figure 5.1), when much of the existing agricultural land was probably nutrient deficient and required substantial fertilisation to improve crop yield. And because livestock numbers were low, the animals did not produce enough manure to meet the nutrient requirements. Moreover, just after WOII manure was not valued for phosphorus. Only the last 15 odd years farmers take P from manure fully into account. Fertiliser consumption has gradually decreased since then. Pagina 45

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