Beyond mines: living with less phosphorus by increasing soil phosphorus recycling

YUNUEN TAPIA TORRES; FELIPE GARCÍA-OLIVA; ALBERTO MORÓN; EMILY SOL GARCÍA MARTÍNEZ; PAMELA CHÁVEZ ORTIZ

San Diego, California

Congreso; SSSA International Soils Meeting; 2019

Phosphorus plays a fundamental role in all living cells. It is essential in fertilizers used in food production. However, the agri-food systems are dependent on P sourced from finite phosphate rock reserves that are becoming increasingly scarce and expensive; which limits the producers? access to fertilizer markets and reduces our ability for food production. Therefore, changes are needed to create a more sustainable and resilient agri-food system, which involves among others, increasing knowledge about soil P dynamics. An alternative is to increase the soil P biological recycling, and in this way, reduce the fertilizers use. It is well-known that in soils, microorganisms are primarily responsible for P recycling, manipulating the pool of available P through a variety of P transformation processes. P forms in ecosystems are diverse but dissolved inorganic phosphate (Pi) is the main P source for microorganisms and plants, however its availability is very low and microbes have evolved numerous mechanisms for uptake and storage of Pi in response to nutrient scarcity. We will present the results obtained after ten years of studying the soil P dynamics under different redox potential in Mexico. The soil genetic resources regulate the organic P recycling by the synthesis of exoenzymes or organic acids and therefore regulate different P transformation processes. The diversity of genetic resources (analysed by soil bacterial isolates, soil 16S amplicon libraries and metabolic capacities) is correlated with the dominance of P fraction (analysed by sequential P fractionation) and therefore regulates the increase or decrease of soil P availability. Our results revealed that different strategies for P utilization were distributed between and within the different taxonomic lineages analysed, suggesting a dynamic movement of P utilization traits among soil bacteria in microbial communities. Microbes could be an alternative to increase ecosystem P recycling and to reduce the use of phosphate fertilizers.