Title: Litter quantity, litter chemistry, and soil texture control changes in soil organic carbon fractions under bioenergy cropping systems of the North Central U.S.

Abstract

Soil organic carbon (SOC) storage is a critical component of the overall sustainability of bioenergy cropping systems. Predicting the influence of cropping systems on SOC under diverse scenarios requires a mechanistic understanding of the underlying processes driving SOC accumulation and loss. We used a density fractionation technique to isolate three SOC fractions that are conceptualized to vary in SOC protection from decomposition. The free light fraction (FLF) is particulate SOC that is present in the inter-aggregate soil matrix, the occluded light fraction (OLF) is contained within aggregates, and the heavy fraction (HF) is associated with minerals. We evaluated surface (0 to 10 cm depth) SOC fraction changes from baseline conditions 5 years after biofuel cropping system establishment at two temperate sites with contrasting soil textures. The biofuel cropping systems included no-till maize, switchgrass, prairie, and hybrid poplar. The FLF concentration (g fraction C g bulk soil-1) did not change significantly from baseline levels under any of the cropping systems at either site after 5 years. Except for poplar, OLF concentrations were reduced in all systems at the site with coarse-textured soils and maintained at the site with fine-textured soils. In poplar systems, OLF concentrations were maintained on coarse-textured soils andmore » increased on fine-textured soils. The HF concentrations also increased under poplar on the coarse-textured soil. A structural equation model indicated that OLF concentrations increased with lower litter C:N, and HF concentrations increased with greater litter quantity and lower litter C:N mass ratios. C:N increased over time within all SOC fractions, suggesting that all pools are sensitive to land-use change on sub-decadal timescales. In agreement with modern SOC theory, our empirical results indicate that increasing litter input quantity and promoting plant species with low C:N litter may improve SOC storage in aggregate and mineral-associated soil fractions.« less

Authors:

von Haden, Adam C.  ^[1];

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Kucharik, Christopher J. ^[2]; Jackson, Randall D. ^[2]; Marín-Spiotta, Erika ^[3]

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+ Show Author Affiliations

1. Univ. of Wisconsin, Madison, WI (United States). Nelson Inst. for Environmental Studies; Univ. of Wisconsin, Madison, WI (United States). DOE Great Lakes Bioenergy Research Center; Univ. of Illinois, Urbana-Champaign, IL (United States). DOE Center for Advanced Bioenergy and Bioproducts Innovation
2. Univ. of Wisconsin, Madison, WI (United States). Nelson Inst. for Environmental Studies; Univ. of Wisconsin, Madison, WI (United States). DOE Great Lakes Bioenergy Research Center; Univ. of Wisconsin, Madison, WI (United States). Dept. of Agronomy
3. Univ. of Wisconsin, Madison, WI (United States). Nelson Inst. for Environmental Studies, and Dept. of Geography

Publication Date:

2019-04-27

Research Org.:

Univ. of Illinois, Urbana-Champaign, IL (United States). Center for Advanced Bioenergy and Bioproducts Innovation

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Transportation Office. Bioenergy Technologies Office

OSTI Identifier:

1509697

Grant/Contract Number:  

SC0018420

Resource Type:

Accepted Manuscript

Journal Name:

Biogeochemistry

Additional Journal Information:

Journal Volume: 143; Journal Issue: 3; Journal ID: ISSN 0168-2563

Publisher:

Springer

Country of Publication:

United States

Language:

English

Subject:

09 BIOMASS FUELS; Density fractionation; Soil carbon stabilization; Litter quality; Biofuels; Land-use change