Effects of fertilization, plant species, and intra-specific diversity on soil carbon and nitrogen in biofuel cropping systems after five growing seasons

Adkins, Jaron; Jastrow, Julie D.; Morris, Geoffrey P.; de Graaff, Marie-Anne

doi:10.1016/j.biombioe.2019.105393

Title: Effects of fertilization, plant species, and intra-specific diversity on soil carbon and nitrogen in biofuel cropping systems after five growing seasons

Journal Article · Thu Oct 17 00:00:00 EDT 2019 · Biomass and Bioenergy

DOI:https://doi.org/10.1016/j.biombioe.2019.105393· OSTI ID:1573246

Adkins, Jaron ^[1]; Jastrow, Julie D. ^[2]; Morris, Geoffrey P. ^[3]; de Graaff, Marie-Anne ^[1]

Boise State Univ., Boise, ID (United States)
Argonne National Lab. (ANL), Argonne, IL (United States)
Kansas State Univ., Manhattan, KS (United States)

Land-use change for bioenergy production can release greenhouse gases (GHG) through disturbance of soil carbon (C) pools, but use of native species with extensive root systems as bioenergy crops may help mitigate GHG emissions by enhancing soil C sequestration. Here, we investigated how (1) fertilization, (2) plant species and cultivars, and (3) inter- and intra-specific diversity affect soil C and N accumulation five growing seasons after conversion of an old-field dominated by C₃ grasses to a grassland dominated by C₄ perennial grasses managed for biofuel production. We manipulated diversity at both the species- and cultivar level, and applied nitrogen (N) at two levels (0 and 67 kg ha^–1). Establishment of C₄ grass treatments on soils that supported C₃ pasture grasses for 36 years enabled us to use the natural abundance C isotope ratio technique to estimate the contribution of new C₄ plant-derived C to soil organic matter pools. Our study yielded three main results: 1) annual fertilization did not significantly affect soil C and N concentrations after five growing seasons; 2) increasing inter- and intra-specific diversity did not significantly increase soil C and N concentrations; 3) cultivar- and species identity influenced C₄-derived C and total soil C concentrations: big bluestem dominated stands exhibited greater soil C accrual relative to stands dominated by switchgrass and mixed-species treatments. Here, future research is needed to further assess how big bluestem can aid in the sustainable provisioning of second generation biofuel feedstocks.

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Research Organization:: Argonne National Lab. (ANL), Argonne, IL (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Biological and Environmental Research (BER); U.S. Department of Agriculture (USDA), National Institute of Food and Agriculture (NIFA)