P fertilization experiments require reinterpretation: Abiotic elevation of available C and N could influence microbial processes in soil

Traditionally, stimulation of soil microbial respiration by phosphorus (P) fertilization was interpreted as a relieved P limitation of soil microbial activity by P supply. However, recent studies suggest that the stimulated microbial respiration is due to the abiotic elevation of carbon (C) because P desorbs C from soil mineral surfaces, elevating microbially available C and thereby stimulating microbial respiration. This new interpretation of P -mediated elevation of soil microbial respiration implies the need for caution when interpreting the effects of P fertilization on other soil microbe-mediated processes. Soil microbial biomass, microbial community shifts, enzyme production, C mineralization, nitrous oxide emissions, and other microbe-mediated processes in soil should be affected by the abiotic elevation of available C and nitrogen, because these elements are essential for soil microorganisms and the processes they mediate. Results of any P fertilization experiments investigating the impact of P addition on soil microbial processes may require reinterpretation.

Automated summary

Traditionally, it was believed that phosphorus (P) fertilization relieved the limitation of soil microbial activity by providing P. Recent studies, however, suggest that the stimulation of microbial respiration is actually due to the release of carbon (C) from soil minerals caused by P, which increases microbially available C and stimulates microbial respiration. This new understanding has implications for interpreting the effects of P fertilization on other soil microbe-mediated processes.