About this Research Topic
Phosphorus (P) is an essential nutrient for vascular plants and the primary source of this nutrient is the soil. Large amounts of P are contained in soils, but only a small percentage of this, typically less than 5%, is directly available for use by plants.
Many soils globally are P deficient and the world's agriculture requires phosphate fertilizer inputs to optimise primary production. However, part of the applied P is accumulated in soils in non-labile forms due to its high-affinity reactions with soil particles and its occlusion as stable compounds. Likewise, the accumulation of P in organic forms associated with the build-up or stabilization of soil organic matter is common. This accumulated P is known as legacy-P.
The continued fertilizer applications beyond plant requirements have led to a build-up of legacy-P in soils, which are forms of P with lower availability for plants. Unfortunately, this imbalanced P input:output ratio is necessary in order to maintain satisfactory yields in conventional agricultural systems, the consequences of which are of global importance regarding the environmental preservation and sustainability of agricultural systems. In these high-P soils, if sediments are transferred to water bodies by erosion, the consequent environmental pollution of entrained P is one of the main drivers of water eutrophication. Moreover, as phosphate rock reserves with economic viability to mine are finite and a non-renewable resource, the agricultural systems needs to be redesigned to achieve a better balance between inputs and outputs of P and postpone a future scenario of scarcity.
New strategies need to be implemented in order to improve the P efficiency of crop systems, including readjusting fertilizer recommendations, adoption of best management practices, use of crop rotations including P-mobilizing species, intensification of use of by-products and waste, and continuous revision of environmental regulations to avoid P excesses. Moreover the reengineering of plant, fertilizer, and microorganism processes are needed, as the development of P-efficient cultivars, novel fertilizers with enhanced efficiency, and stimulating beneficial associations between plants and microorganisms can all extend the root system or mobilize P in the rhizosphere. All these strategies can increase the use of legacy-P from soil and contribute to the reduction of inputs of phosphate fertilizers, therefore leading to a better use of phosphorus in agriculture.
In this Research Topic of Frontiers in Earth Science, we welcome the scientific community to contribute with research reporting recent advances on various aspects including:
• The potential use of legacy-P in agriculture;
• Quantitative and qualitative methods for measuring legacy-P;
• Sustainable management of P fertilizers; and
• Strategies employed by microorganisms and plants to mobilize and use the P in soils.
We welcome the submission of Original Research articles, Reviews or Systematic Reviews, Policy and Practice Reviews, Perspectives, Opinions, Methods, and Data Reports.
Keywords: Phosphorus, Soil, Residual P, Legacy P, Fertilizerse
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.