A substance flow analysis of phosphorus in the food production, processing and consumption system of the Netherlands

Phosphorus (P) is an essential nutrient in agriculture. In recent years 15-18 Mt of P was used as mineral fertilizer in the global food production chain. The major source of this fertilizer is phosphate rock which is unfortunately a finite resource. In the long term this necessitates efficient use of fertilizer and optimized recycling of P rich waste streams (including manure). In order to determine the potential for sustainable use of P we performed a 3-year substance flow analysis (SFA) for the Netherlands, a country characterized by its intensive agriculture and a high livestock density. Such conditions occur in various regions of the world and can easily result either in environmental problems or an unsustainable use of P. Annual quantification of P flows were performed in 2005, 2008 and 2011. These were not restricted to agriculture. Industrial, household/retail and the environmental P-flows were also included. Due to relatively high quantities of feed imports, the national P-surplus amounted to almost 60 Mkg P in 2005, decreasing to 42 Mkg in the year 2011. A large proportion of this reduction was considered to be due to reductions in P fertilizer use. The SFA provided an insight into the fate of the national P surplus and the potential for recycling. In 2011 the major part of the 42 Mkg of P surplus was observed in waste streams from society (23 Mkg, e.g. sewage sludge incineration ashes, household refuse). During this study these waste streams were not reused within the national food production system or elsewhere. The remainder of the surplus accumulated in agricultural soils (around 12 Mkg) or were emitted through surface water (almost 7 Mkg).