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

Abstract

a b s t r a c tLand 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 Functional differences in microbial communities were highlighted by contrasting processing of labelled C. SRC willow allocated 44% of total 13 C detected into fungal PLFA relative to 9% under miscanthus and 380% more 13 C 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. Crown

Environmental and microbial controls on microbial necromass recycling, an important precursor for soil carbon stabilization

“…Analytical Technologies Inc., USA) streamed to a G-2131i cavity ring down spectroscopy (CRDS) isotopic analyzer (Picarro Inc., USA) 46 . These values and the mass of necromass used in each assay were used to calculate δ 13 C of the substrate.…”

Real‐time monitoring of greenhouse gas emissions with tall chambers reveals diurnal N2O variation and increased emissions of CO2and N2O fromMiscanthusfollowing compost addition

“…20.00 and 09.00. Pulse labelling with 13 C in Miscanthus at this site has shown that C is available to soil microbes four hours after assimilation (Elias et al, ), and with highest rates of NEE seen from 11.00 to 15.00, photosynthate should start to arrive at the rhizosphere around 15.00. This coincided with the increase in N 2 O fluxes, and the arrival of plant C to the soil late in the day might also explain why R s remained above the daily average throughout the night time, despite coinciding with the lowest soil temperatures.…”

Plant identity control on soil food web structure and C transfers under perennial bioenergy plantations

“…Within each plantation, four rectangular pulse chambers (6 m long x 2.5 m wide x 3 m high) were erected over the entire experimental plot (for full description of the experimental set-up see Elias et al, 2017). Briefly, a chamber volume of 45 m 3 allowed for the inclusion of two double rows of willow trees 1.5 m apart, whilst Miscanthus giganteus was randomly distributed in the 15 m 2 area.…”

“…Ostle et al, 2007;Seeber et al, 2012;Crotty et al, 2014;Huang et al, 2015). Nevertheless, very few have been performed in bioenergy crops (Tavi et al, 2013;Chaudhary and Dick, 2016;Elias et al, 2017) and our study is the first one trying to link soil macrofauna and rhizosphere carbon flow in these systems.…”

“…We also anticipated that, due to differences in root morphology and associated symbionts as well as in litter quality, earthworm and microbial (PLFA) community structures would differ between Miscanthus and SRC willow. The study took advantage of a parallel study performed at the same site (Elias et al, 2017) which found a higher below-ground C allocation under SRC willow (relative to Miscanthus) that was rapidly assimilated by fungi. We therefore predicted higher heterotrophic activities under this plantation and a rapid assimilation of labile C by soil biota through fungal grazing.…”