Abiotic and biotic drivers of struvite solubilization in contrasting soils

19 páginas.- 4 figuras.- 1 tabla.- referencias.- Supplementary material for this article can be found in the online version.https://doi.org/10.1016/j.pedsph.2023.03.014

Phosphorus (P) limitation in the coming decades calls for the utilization of alternative fertilizers in agriculture. Struvite is a promising P source, but its potential fertilizer role is dependent on different physical, chemical and biological properties, which are very heterogeneous in soil and complicate the prediction of the best soil conditions for its application. Here, we evaluated the solubility of struvite in soil, its redistribution into P fractions, and its potential abiotic and biotic drivers in 62 globally-distributed soils with contrasting properties through an incubation assay. We found that after 40 days, about 35% of the struvite-P is redistributed into soil fractions that are more accessible to plants and microbes. P redistribution from struvite is driven by a complex suite of chemical, physical, environmental and microbial properties that varied across soils. Soil texture played a critical role in determining the entrapping of P in struvite-amended soils in soluble (H2O), labile (NaHCO3), and moderately labile (NaOH) fractions. In addition, the soil cations solution was one the most important driver for struvite-P available fractions. The great importance of texture and cations in determining struvite-P fractions in soil contrasted with the relatively minor role of pH. At the microbial level, the number of bacterial operational taxonomic units (OTUs) from the original soils that correlated with struvite-P fractions was higher than that of fungi. In comparison with the soluble fraction (PH2O), the number of OTUs that correlated with the struvite-P labile fraction (PNaHCO3) was dominated by bacteria rather than by fungi. Overall, this study provided a predictive framework of the potential use of struvite as a P fertilizer in contrasting soils.

ARN is thankful for the financial support by the Fundación General CSIC (Programa ComFuturo). This research is part of the project PID2020-114942RB-I00 funded by MCIN/ AEI/ /10.13039/501100011033. M.D-B. is supported by a project from the Spanish Ministry of Science and Innovation (PID2020-115813RA-I00), and a project of the Fondo Europeo de Desarrollo Regional (FEDER) and the Consejería de Transformación Económica, Industria, Conocimiento y Universidades of the Junta de Andalucía (FEDER Andalucía 2014-2020 Objetivo temático “01 - Refuerzo de la investigación, el desarrollo tecnológico y la innovación”) associated with the research project P20_00879 (ANDABIOMA). C C-D is supported by a Post-Doc Scholarship in the context of the FCT funded project “Soil Ecosystems in the XXI Century: drivers, conservation and future scenarios”, with the reference FCT-PTDC/BIACBI/2340/2020 and led by the Polytechnic Institute of Viana do Castelo (IPVC).

Peer reviewed