Anaerobic soil disinfestation using diluted ethanol increases phosphorus availability in arable Andosols

Very few studies to date have focused on phosphorus (P) dynamics and microbial P acquisition during anaerobic soil disinfestation (ASD), an alternative to chemical soil fumigation for soil diseases. We evaluated the effects of ASD using diluted ethanol as well as the effects of drying treatments following ASD on available P concentrations, phosphomonoesterase activity, microbial biomass P, and microbial community compositions, including those harboring the alkaline phosphomonoesterase gene (phoD), in two arable Andosols. An increase in the Bray-2P concentration and a decrease in the ratio of phosphomonoesterase/β-D-glucosidase activities were observed during ASD in both soils, indicating an increase in P availability during ASD. A significant negative correlation between the diversity of profile of denaturing gradient gel electrophoresis for phoD-harboring community and alkaline phosphomonoesterase activity was found, suggesting that a less diverse bacterial group might produce alkaline phosphomonoesterase in soils with higher activity. ASD followed by drying and rewetting significantly increased the Bray-2P concentration and microbial biomass P in one Andosol. These results support the potential of ASD to increase P availability in addition to suppressing soil-borne diseases in arable Andosols.