The potential bioavailability of phosphorus and the microbial community involved in agro-industrial composts as organic amendments or growing media

Harnessing agro-industrial residues through composting is gaining importance as a means of phosphorus recovery, as is its reutilization as plant available phosphorus. This research seeks to analyze various combinations of agroindustrial waste and observe the microbial communities contributing to the availability of this element for plants. Six composts were used with different proportions of agroindustrial waste. Phosphorus fractionation was carried out, and the available phosphorus was determined. The molecules involved in phosphorus mineralization and solubilization, alkaline phosphatase activity, organic acids, and microbial communities were also determined. Finally, the potential phosphorus genes (Inorganic P solubilization genes (gcd, ppx, ppqC), and Organic P mineralization genes (phoA, phoD, phnL, phnl, phnJ, phnP, phnH, and phnG)) present in the analyzed composts were established. Compost X2B, composed of vineyard and tomato residues, demonstrated superior performance in providing available phosphorus compared to other composts. This was determined by microbial communities harboring genes involved in the phosphorus cycle, facilitating phosphorus availability.