Phosphorus mineralization can be driven by microbial need for carbon

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• 作者：Marie Spohn ; ^{mspohn1@gwdg.de} ; Yakov Kuzyakov
• 关键词：Phosphorus recycling ; Organic phosphorus ; Soil microorganisms ; Carbon limitation ; Phosphorus mineralization
• 刊名：Soil Biology & Biochemistry
• 出版年：2013
• 出版时间：June, 2013
• 年：2013
• 卷：61
• 期：Complete
• 页码：69-75
• 全文大小：808 K

文摘

Despite the importance of phosphorus (P) mineralization to maintain soil fertility, little is known about the mechanisms that regulate microbial P mineralization. We tested the hypothesis that microbial P mineralization can be driven by microbial need for carbon (C). For this purpose, net microbial uptake kinetics of ¹⁴C and ³³P from glucose-6-phosphate were studied in a Leptosol depending on availability of C, nitrogen (N), and P. After 60?h of incubation, 16.4 % of the ¹⁴C from glucose-6-phosphate was recovered in the microbial biomass, while ³³P incorporation into the microbial biomass was a third less. The higher net uptake of ¹⁴C than of ³³P from the glucose-6-phosphate indicates that soil microorganisms use the organic moiety of phosphorylated organic compounds as a C source, but only use a small proportion of the P. Hence, they mineralize P without incorporating it. Our finding that the net uptake of ¹⁴C and ³³P in the soils amended with inorganic P did not differ from the control treatment indicates that P mineralization was not driven by microbial need for P but rather for C. In a second experiment with three temperate forest soils we found that the activity of ¹⁴C from glucose-6-phosphate in soil solution decreased faster than the activity of ³³P from glucose-6-phosphate. This might suggest that higher net uptake of C than of P from glucose-6-phosphate can also be observed in other temperate forest soils differing in C, N, and P contents from the Leptosol of the main experiment. In conclusion, the experiments show that microbial P mineralization can be a side-effect of microbial C acquisition from which plants potentially can benefit.