Advances and Perspectives to Improve the Phosphorus Availability in Cropping Systems for Agroecological Phosphorus Management

Phosphorus (P) is a limiting nutrient for the productivity of many agroecosystems, and the depletion of global mineral P reserves is of concern for global food security. On the other hand, overfertilization with P and its subsequent export through runoff can cause eutrophication of water bodies and natural terrestrial habitats. An important challenge is therefore to develop productive farming systems in which P availability in soils is increased, while reducing mineral P inputs, outputs, and negative off-site impacts. Increasing the P availability in cropping systems requires several approaches including management of soil properties and P amendments, agroecology of cropping systems, and plant breeding. The objective of the present review is to identify new research perspectives in agronomy and emerging strategies to improve the P availability in cropping systems. For this purpose, we explore the following: (1) the use of renewable waste-derived P resources (including crop residues, excreta, struvite, and biochar) to improve P availability, particularly the impacts of applications of such renewable P sources on the chemical properties of the soil, soil organic matter dynamics, soil microbial and rhizospheric activity, and, ultimately, P availability; (2) the effects of multispecies cropping system on P availability, notably the incorporation of the concepts of positive plantesoil feedback on P availability, previously demonstrated in grassland and forest ecosystems, to multispecies cropping systems; and (3) the identification of genetic traits of plantemicroorganism relations involved in the tolerance of low-P soils to improve plant breeding outcomes. The challenge for sustainable management of P resources for agriculture is now to reengineer agricultural systems at several scales and to define P management strategies in cropping systems by combining the use of renewable P resources and the management of soil properties, multispecies cropping system, and crop cultivars that increase soil P availability.