Consider the fate of the approximately 17.5 million tonnes of phosphorus mined in 2005, analysed in the paper by Cordell et al. About 14 million tonnes of this were used in fertilizer (much of the rest went into cattle-feed supplements, food preservatives, and the production of detergents and industrial cleaning agents) but only about 3 million tonnes made it to the fork (or chopstick). The largest loss — around 8 million tonnes — was directly from farms through soil leaching and erosion” [Elser & Bennett 2011: 30].
To handle the twin problems of phosphorus pollution and scarcity, strategies for phosphorus conservation and recycling are urgently needed.
The solutions to these problems lie in recapturing and recycling phosphorus, moving it from where there is too much to where there is too little, and developing ways to use it more efficiently. Many strategies are simple and readily available, even for poor farmers and developing economies [Elser & Bennett 2011: 30].
The authors’ solutions include: widespread adoption of agricultural conservation practices, reduction of food waste (at least in part by producing food within or closer to cities), recycling human waste, reducing meat consumption, recovering nutrients from confined livestock facilities (such as through bioreactors), and genetically engineering plants and animals to require lower phosphorus inputs. No mention in this article of the role of plant-fungi symbiosis in accessing phosphorus in the soil.
Elser, James & Elena Bennett, 2011, A broken biogeochemical cycle, Nature 478: 29-31, https://www.nature.com/articles/478029a