Biosolid Application to Agricultural Land—a Contribution to Global Phosphorus Recycle: A Review

Phosphorus (P) is an essential nutrient required for plant development. Continuous population growth and rising global demand for food are expected to increase the demand for phosphate fertilizers. However, high–quality phosphate rock reserves are progressively becoming scarce. Part of the increased pressure on P resources could be alleviated by recycling P present in biosolids. Therefore, it is crucial to understand the dynamics of P in biosolid–amended soils, the effects of residual biosolid–borne P in soils, the way in which microorganisms may control P dynamics in biosolid–amended soils and the environmental implications of the use of biosolids as a source of P. Further research is needed to maximize biosolid–borne P uptake by crops and minimize its loss from biosolid–amended soils. The analysis of the microbiological control of P dynamics in biosolid–amended soils indicates interactions of biosolid P with other nutrients such as carbon (C) and nitrogen (N), suggesting that harmonization of the current regulation on the use of biosolids in agriculture, mainly based on total N and pollutant contents, is needed to better recycle P in agriculture.