Rate of Phosphorus Cycling Correlated with Microbial Activities.

Phosphorus in soil is actively taken up by biota as well as cycled between biotic and abiotic environments.  Aim of this study was to develop a rate law between phosphorus uptake and cycling, and microbial activities in pure culture as well as in soil system. We measured changes in phosphate oxygen isotopes (δ¹⁸O_p) along with cell respiration, production of dehydrogenase activities (DHA) and phosphatase enzyme activities. Our results showed that the proportional relationship exists between changes in δ¹⁸O_p and microbial activities. Effect of vertical diffusion of CO₂ and O₂ in soil as a result of changes in soil moisture and ambient humidity was found to influence the field measured data on soil respiration. However, trend of P cycling with microbial activity was similar in pure culture and in soil system. These results have important implication on P uptake and cycling in soil.