Phosphorus budget in the water-agro-food system at nested scales in two contrasted regions of the world (ASEAN-8 and EU-27)

Phosphorus (P) plays a strategic role in agricultural production as well as in the occurrence of freshwater and marine eutrophication episodes throughout the world. Moreover, the scarcity and uneven distribution of minable P resources is raising concerns about the sustainability of long-term exploitation. In this paper we analyze the P cycle in anthropic systems with an original multi-scale approach (world region, country, and large basin scale) in two contrasting world regions representative of different trajectories in the socioeconomic development for the 1961–2009 period: Europe (EU-27)/France and the Seine River Basin, and Asia (ASEAN8)/Vietnam and the Red River Basin. Our approach highlights different trends in the agricultural and food production system of the two regions. Whereas crop production increased until the 1980s in Europe and France and has stabilized since then, it began to increase in the 1980s in ASEAN-8 and Vietnam, where it is still increasing today. This trend is related to the increasing use of fertilizers, although in EU-27 countries the amount used until the 1980s was so high that even their sharp decrease after this date did not change the total crop production. Total P delivered at the outlet of the river basins is three times higher for ASEAN-8 (300 kgP km-2 yr-1) than for EU-27 countries (100 kgP km-2 yr-1), and twice as high in the Red River (200 kgP km-2 yr-1) as in the Seine River (110 kgP km-2 yr-1), with about three times more agricultural losses to the hydrosystem in ASEAN-8 compared to EU-27. The study also discusses different management and policy measures according to the peculiarities of the two world regions, integrating the perspective of surface water quality with agricultural issues (fertilizers, crop production, and surplus), food/feed exchanges, and diet, and defining the so-called water-agro-food system. We consider that the river basin scale is a relevant scale for both scientific assessments and implementation of policies.

JRC.H.1 - Water Resources