The issues for P availability to agricultural plants are threefold: the solution concentration of P during early growth (intensity factor); the quantity of P in the soil 'bank' to meet plant and animal needs (capacity or quantity factor); and the rate at which P becomes available from mineral and organic sources (kinetic factor).These three needs can be met by:1) applying traditional (manure, compost) and novel (biosuper) sources2) modifying or selecting plants for their root architecture, phytase activity, carboxylate excretion and P translocation inefficiency3) encouraging rhizosphere conditions which favour phytase and carboxylase activity4) developing symbioses with mycorrhiza and Penicillium species5) developing exoenzyme products which release inositol P6) adjusting soil pH to 6-7 for maximum availability of native mineral P sources or lowering pH for maximum availability of reactive rock P7) developing rotations which maximise organic P cycling.These seven broad groupings of strategies to improve P nutrition each operate by one or more of the three mechanisms of quantity, intensity and kinetic factors. The possible application of these strategies to 'organic' farming is outlined in this review. However a successful application of these strategies might also improve the P efficiency of conventional agriculture.
Conyers, M., & Moody, PW. (2009). A conceptual framework for improving the P efficiency of organic farming without inputs of soluble P fertiliser. Crop and Pasture Science, 60(2), 100-104. https://doi.org/10.1071/CP06327