Soil Characteristics Rather Than Microbial Inoculation Determines The Effects Of Alternative Phosphorus-Fertilizers On Ryegrass Yield And The Soil Microbial Community

Abstract With global phosphate rock resources declining for conventional fertilizers, there is growing interest in exploring alternative, more sustainable materials to enhance soil fertility and crop yield production. Additionally, leveraging microorganisms to improve phosphorus (P) availability in soils is an appealing approach for sustainable agriculture. This study evaluates the effects of different P-rich materials, including struvite (STRU), meat and bone meal (MBM), and phosphate rock (PR), combined with a microbial consortium with P-solubilizing and plant growth-promoting capabilities, on P availability and plant growth in two soils with contrasting physicochemical properties. To achieve these goals, a pot experiment was conducted to assess P content in soil, ryegrass, and microbial biomass, along with microbial enzyme activity and community composition using microbial fatty acid analysis. The experiment involved two soils with contrasting characteristics, amended with conventional monoammonium phosphate (CHEM), STRU, MBM, and PR, with or without microbial inoculation. Soil characteristics and the type of P fertilizer significantly influenced P availability, ryegrass uptake, and plant yield. Microbial inoculation did not increase soil P or ryegrass yield. Fatty acid analysis showed microbial community changes with soil characteristics and fertilizer. Struvite performed similarly to CHEM, while MBM was less effective than struvite but better than PR as a P fertilizer. Our study found that soil characteristics and the type of phosphate fertilizer affected soil P dynamics in the soil–plant system. Recycled P-based fertilizers offer sustainable alternatives to synthetic ones, potentially alleviating agricultural challenges.