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Functional differences in the microbial processing of recent assimilates under two contrasting perennial bioenergy plantations

Elias, Dafydd M.O., Rowe, Rebecca L., Pereira, M. Glória, Stott, Andrew W., Barnes, Christopher J., Bending, Gary D., McNamara, Niall P.
Soil biology & biochemistry 2017 v.114 pp. 248-262
Miscanthus giganteus, bacteria, bioenergy, carbon, community structure, coppicing, energy crops, fungi, land use change, microbial communities, phospholipid fatty acids, plant tissues, plantations, soil, soil microorganisms, soil respiration, United Kingdom
Land use change driven alteration of microbial communities can have implications on belowground C cycling and storage, although our understanding of the interactions between plant C inputs and soil microbes is limited. Using phospholipid fatty acids (PLFA's) we profiled the microbial communities under two contrasting UK perennial bioenergy crops, Short Rotation Coppice (SRC) willow and Miscanthus Giganteus (miscanthus), and used 13C – pulse labelling to investigate how recent carbon (C) assimilates were transferred through plant tissues to soil microbes. Total PLFA's and fungal to bacterial (F:B) ratios were higher under SRC willow (Total PLFA = 47.70 ± 1.66 SE μg PLFA g−1 dry weight soil, F:B = 0.27 ± 0.01 SE) relative to miscanthus (Total PLFA = 30.89 ± 0.73 SE μg PLFA g−1 dry weight soil, F:B = 0.17 ± 0.00 SE). Functional differences in microbial communities were highlighted by contrasting processing of labelled C. SRC willow allocated 44% of total 13C detected into fungal PLFA relative to 9% under miscanthus and 380% more 13C was returned to the atmosphere in soil respiration from SRC willow soil compared to miscanthus. Our findings elucidate the roles that bacteria and fungi play in the turnover of recent plant derived C under these two perennial bioenergy crops, and provide important evidence on the impacts of land use change to bioenergy on microbial community composition.