P<scp>HOSPHORUS IN THE</scp>E<scp>NVIRONMENT</scp>: Natural Flows and Human Interferences

TLDR

Phosphorus is essential for life but cycles slowly, with low solubility making it a growth‑limiting nutrient; global food production depends heavily on phosphates, yet losses to water bodies cause widespread eutrophication and raise concerns about long‑term inorganic supply. The study aims to evaluate whether more efficient fertilization can reduce non‑point phosphorus losses. Human activities have tripled global phosphorus mobilization by 2000, driven mainly by soil erosion, runoff, residue recycling, industrial discharges, and especially inorganic fertilizer use, while sewage treatment often fails to control P, leading to elevated phosphorus in treated wastewater.

Abstract

▪ Abstract Phosphorus has a number of indispensable biochemical roles, but it does not have a rapid global cycle akin to the circulations of C or N. Natural mobilization of the element, a part of the grand geotectonic denudation-uplift cycle, is slow, and low solubility of phosphates and their rapid transformation to insoluble forms make the element commonly the growth-limiting nutrient, particularly in aquatic ecosystems. Human activities have intensified releases of P. By the year 2000 the global mobilization of the nutrient has roughly tripled compared to its natural flows: Increased soil erosion and runoff from fields, recycling of crop residues and manures, discharges of urban and industrial wastes, and above all, applications of inorganic fertilizers (15 million tonnes P/year) are the major causes of this increase. Global food production is now highly dependent on the continuing use of phosphates, which account for 50–60% of all P supply; although crops use the nutrient with relatively high efficiency, lost P that reaches water is commonly the main cause of eutrophication. This undesirable process affects fresh and ocean waters in many parts of the world. More efficient fertilization can lower nonpoint P losses. Although P in sewage can be effectively controlled, such measures are often not taken, and elevated P is common in treated wastewater whose N was lowered by denitrification. Long-term prospects of inorganic P supply and its environmental consequences remain a matter of concern.