Only 12.6 pct inorganic phosphorus fertilizers taken up by plants globally: study

Phosphorus is an essential element for the growth, development, and reproduction of all life forms.

Among tens of millions tonnes of inorganic phosphorus fertilizers used every year in the world, only 12.6 percent is absorbed by plants, with the majority stored in soils, according to a recent study by botanists from the Chinese Academy of Sciences (CAS).

A worker stores fertilizers at a phosphatic fertilizer factory in Yichang City, central China's Hubei Province, March 20, 2020. (Xinhua/Cheng Min)

A research team from the South China Botanical Garden under the CAS has established a global database, which includes 987 sets of observation data from 274 papers published between 1972 and 2021, to study the proportions of inorganic phosphorus fertilizer in terms of plant uptake, soil storage, and leaching loss.

The quantitative analysis based on the database finds that, on a global average, only about 12.6 percent of inorganic phosphorus fertilizer is absorbed and utilized by plants, 67.2 percent is stored in the soil, and about 4.4 percent is lost from the ecosystem. The majority of those stored in the soil exists in the form of inactive inorganic phosphorus.

The result also shows that excessive fertilization is the main reason for the decline in the utilization rate of phosphorus fertilizer by plants, and soil pH value and bulk density are also important factors affecting the phosphorus’ uptake efficiency and flow.

According to the study published in the journal One Earth, these findings deepen the understanding of the phosphorus cycle in terrestrial ecosystems and offer valuable guidance for the management of phosphorus fertilizer in agricultural practices.

Phosphorus is an essential element for the growth, development, and reproduction of all life forms. As human demand for food and timber continues to rise, so does the demand for inorganic phosphorus fertilizers, whose primary raw material is phosphate rock. The current global reserves of phosphate rock are only sufficient for about 400 years of mining at most.

The inefficient use of phosphorus fertilizers has led to increased phosphorus levels in water bodies, causing environmental issues around the world. To alleviate the supply shortage of phosphorus resources and the environmental issues, it is urgent to gain a deeper understanding of the flow of inorganic phosphorus fertilizers in terrestrial ecosystems and the main influencing factors.