The impacts of four potential bioenergy crops on soil carbon dynamics as shown by biomarker analyses and DRIFT spectroscopy. Issue 7 (11th May 2018)

• Record Type: Journal Article
• Authors: Zhu, Xuefeng; Liang, Chao; Masters, Michael D.; Kantola, Ilsa B.; DeLucia, Evan H.
• Is Part Of: Global change biology. Volume 10:Issue 7(2018)
• Page Start: 489
• Page End: 500
• Publication Date: 2018-05-11
• Subjects: amino sugars -- biomarker -- diffuse reflectance mid‐infrared Fourier transform spectroscopy -- maize–maize–soybean rotation -- microbial residue -- neutral sugars -- perennial bioenergy crops -- soil organic carbon decomposition -- soil organic carbon stability; Biomass energy -- Periodicals; Biomass energy -- Environmental aspects -- Periodicals; Energy crops -- Periodicals; 662.88
• DOI: 10.1111/gcbb.12520
• Languages: English
• ISSNs: 1757-1693

Abstract

Abstract: Perennial bioenergy crops accumulate carbon (C) in soils through minimally disturbing management practices and large root inputs, but the mechanisms of microbial control over C dynamics under bioenergy crops have not been clarified. Root‐derived C inputs affect both soil microbial contribution to and degradation of soil organic matter resulting in differing soil organic carbon (SOC) concentrations, storage, and stabilities under different vegetation regimes. Here, we measured biomarker amino sugars and neutral sugars and used diffuse reflectance mid‐infrared Fourier transform spectroscopy (DRIFTS) to explore microbial C contributions, degradation ability, and SOC stability, respectively, under four potential bioenergy crops, M .× giganteus ( Miscanthus × giganteus ), switchgrass ( Panicum virgatum L .), a mixed prairie, and a maize ( Zea mays L .)–maize–soybean ( Glycine max(L.) Merr .) (MMS) rotation over six growing seasons. Our results showed that SOC concentration (g/kg) increased by 10.6% in mixed prairie over the duration of this experiment and SOC storage (Mg/ha) increased by 17.0% and 15.6% in switchgrass and mixed prairie, respectively. Conversion of row crops to perennial grasses maintained SOC stability and increased bacterial residue contribution to SOC in M .× giganteus and switchgrass by 20.0% and 15.0%, respectively, after 6 years. Degradation of microbe‐derived labile SOC was increased in M .× giganteus, and degradation of both labile and stable SOC increased in MMS rotation. These results demonstrate that microbial communities under perennial grasses maintained SOC quality, while SOC quantity increased under switchgrass and mixed prairie. Annual MMS rotation displayed decreases in aspects of SOC quality without changes in SOC quantity. These findings have implications for understanding microbial control over soil C quantity and quality under land‐use shift from annual to perennial bioenergy cropping systems. Abstract : Microbial substrate preference is speculated to be driven by labile carbon inputs and available nitrogen. The results from this study demonstrate optimal conditions for increasing soil organic carbon quantity and quality beyond a cessation of tillage include a diverse aboveground ecosystem, high belowground labile carbon inputs, and available nitrogen.