Response of soil microbial biomass P to addition of different quantities of inorganic P with low soil organic C content

Soil microbial biomass P is considered as the “sources” and “sink” for soil available P. It changes widely and is influenced by many factors. Laboratory incubation was conducted to evaluate the influence of inorganic P on soil microbial biomass P with low soil organic C content. The results showed that soil microbial biomass P and P concentration in biomass increased with the amount of added P under the condition of insufficient C, while soil microbial biomass C did no change significantly with the addition of phosphates. Relationship analysis results indicated that there was significant linear relationship between soil microbial biomass P and soil available P. Similar relationship was found between P concentration in biomass and soil available P. Soil microbial biomass P and P concentration in biomass increased 0.22 mg·kg-1 and 0.73 mg·g-1 respectively with increased 1 mg·kg-1 soil available P.