Improving Phosphorus Bioavailability: Leveraging Plant Traits and Soil Biological Mechanisms

This review addresses the low solubility of orthophosphate ions in soil and the geochemical constraints that limit phosphorus availability to crops. It details how plant-driven rhizosphere processes—root growth and architecture changes, pH modulation, and organic anion exudation—combine with enzyme activities and interactions with soil microorganisms and fauna to enhance phosphorus bioavailability. The article synthesizes modeling and empirical studies on root traits in Poaceae and legume species, the roles of phosphate-solubilizing bacteria and fungi, and the contributions of earthworms and mycorrhizas. It concludes by proposing breeding strategies and ecological approaches to exploit these plant and soil organism mechanisms for more sustainable and efficient phosphorus acquisition by crops.