The global fate of inorganic phosphorus fertilizers added to terrestrial ecosystems

Abstract

More than 25 million tons per year of phosphorus (P) fertilizer from phosphate rock is applied to meet the increasing global food and wood demand despite limited phosphate rock reserves. Yet, the fate of applied inorganic P fertilizer and its drivers have never been systematically explored globally, although doing so can help improve P fertilizer use efficiency. Here, we synthesized 987 field P-addition observations and found that, globally, on average, 12.6% of added inorganic P fertilizer was taken up by plants, 67.2% was stored in the soil and 4.4% was lost. Increased P-addition quantity was the main reason for the decline in plant P uptake. Soil pH and bulk density also modulate the flow of added P to plants, soil, and leaching/runoff loss. Our findings highlight the urgent need to improve P fertilizer use efficiency globally by lowering the P fertilization rate, especially on near-neutral soils with low bulk density.