Does anthropogenic phosphorus input reduce soil microbial resource allocation to acquire nitrogen relative to carbon?

Abstract

We aimed to test if anthropogenic P input into ecosystems reduces microbial resourceallocation to acquire N (and alleviate N shortage if any) because microbes no longerproduce N-rich phosphatase for P acquisition. Literatures reporting the effect of Pfertilization on C-acquiring (β-1,4-glucosidase, BG) and N-acquiring (β-1,4-Nacetylglucosaminidase, NAG, which also acquires C) enzymes were collected andsynthesized. We predicted that P addition elevates BG:NAG especially in P-poorecosystems because P addition alleviates N shortage and reduces the microbial resourceallocation to acquire N relative to C. The synthesized data demonstrated that Pfertilization occasionally reduced BG:NAG, which is inconsistent with the prediction.However, this might not mean that the initial hypothesis was rejected. Stimulatedmicrobial activity and turnover by P fertilization could have caused microbes depend the Csources more on chitin (and peptidoglycan) compared with on cellulose because chitin(and peptidoglycan) is a main component of microbial body and re-provided throughmicrobial turnover. The changes in C resources accompanied by the altered P availabilitymay have largely influenced BG:NAG, masking the role of BG:NAG for indicating microbialresource allocation to C and N acquisitions.