Vegetable greenhouse soil Raw sequence reads. Vegetable greenhouse soil

Understanding soil phosphorus (P) transformation is critical to optimizing P supply to crops while minimizing P loss to water. Nitrogen (N) application in agricultural fields can cause acidification, changing soil chemistry and altering P cycling. In a calcareous vegetable field in China, 13 years of N application (1172 kg N ha-1 yr-1) significantly decreased soil pH, CaCO3, Mehlich-3 extractable magnesium and increased Mehlich-extractable iron (Fe) and aluminum (Al). Nitrogen addition also increased microbial biomass carbon (MBC), decreased alkaline phosphomonoesterase (ALP) activity and changed the total bacterial and phoD-harboring bacterial community structure. Soil total P, Olsen-P and Mehlich P were not affected by N fertilization, but there were significant increases in soil total organic P (Po), NaOH-extractable Po, and the proportion of orthophosphate diesters. Redundancy analysis showed that soil pH, organic carbon, CaCO3, and ALP activity had significant effects on the compositions of soil P (P < 0.05) and could explain 36.4%, 13.3%, 27.5%, and 10.6% of the total variances observed in the composition of P forms. This suggests that soil acidification from N application in this P-rich calcareous soil altered soil abiotic P cycling processes through increasing the chemical adsorption of Po by Fe and Al. It also altered biotic P cycling processes by increasing microbial P uptake and immobilization and decreasing P biochemical mineralization, resulting in Po accumulation.