TITLE:
Potential legacy effects of biofuel cropping systems on soil microbial communities in southern Wisconsin, USA
AUTHORS:
Chao Liang, Gregg R. Sanford, Randall D. Jackson, Teri C. Balser
KEYWORDS:
Lipid Biomarker; Alfalfa; Hay; Corn; Agroecosystem
JOURNAL NAME:
Agricultural Sciences,
Vol.2 No.2,
May
20,
2011
ABSTRACT: Soil microbial community structure is clearly linked to current plant species composition, but less is known about the legacy effects of plant species and agricultural management practices on soil microbial communities. Using microbial lipid biomarkers, we assessed patterns of com-munity-level diversity and abundance at depths of 0-10 and 10-25 cm from three hay (al-falfa/orchardgrass) and two corn plots in south
ern Wisconsin. Principal components analysis of the lipid biomarkers revealed differential composition of the soil microbial communities at the two depths. Despite similar abundance of fungi, bacteria, actinomycete, protozoa, and total microbial lipids in the hay and corn at 0-10 cm, community structure differed with a sig-nificantly higher absolute abundance of arbus-cular mycorrhizal fungi and gram-negative bacteria in the hay plots. No significant micro-bial lipid mass differences were detected be-tween the two management regimes at 10-25 cm, but the proportional dominance of bacterial gram type differed with depth. These results indicate the potential for legacy effects of an-nual and perennial cropping systems manage-ment on microbial community composition and suggests the importance of considering past land-use when initiating long-term agroecolo-
gical trials.