Comparing Biomass Yields of Low-Input High-Diversity Communities with Managed Monocultures Across the Central United Sta
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Comparing Biomass Yields of Low-Input High-Diversity Communities with Managed Monocultures Across the Central United States Mari-Vaughn V. Johnson & James R. Kiniry & Homer Sanchez & H. Wayne Polley & Philip A. Fay
Published online: 24 April 2010 # US Government 2010
Abstract Biofuel cropping expansion is increasing pressure on food, grazing, and conservation lands. Debate over the efficacy of converting diverse native plant communities to managed monocultures prompted us to explore the extensive crop and ecological site productivity databases maintained by US Department of Agriculture-Natural Resources Conservation Service. We compared annual net primary productivity (ANPP) of diverse native plant communities to ANPP of alfalfa (Medicago sativa L.) in Nebraska, Kansas, and Oklahoma; to coastal bermudagrass (Cynodon dactylon [L.] Pers.) in northern and central Texas; and to buffelgrass (Pennisetum ciliare [L.] Link.) in extreme southern Texas. In only 21% of the 1,238 sites in Nebraska, Kansas, and Oklahoma did native communities produce more or equivalent ANPP compared with managed alfalfa or coastal bermudagrass. In contrast, southern Texas native communities had greater ANPP than did buffelgrass at 81% of the sites. Regression analyses based on these results suggested that managed switchgrass
(Panicum virgatum L.) ANPP would consistently exceed native community ANPP. We identified the type of sites that could remain in diverse communities or be converted to diverse communities and have productivity as great as or greater than highly managed monocultures of alfalfa, coastal bermudagrass, or buffelgrass. However, because of the low ANPP on these sites, biomass production may not be the optimal use of such sites. These lands may be better suited to providing other ecosystem services.
M.-V. V. Johnson (*) : J. R. Kiniry : H. W. Polley : P. A. Fay Grassland, Soil, and Water Research Laboratory, USDA-ARS, 808 East Blackland Road, Temple, TX 76502, USA e-mail: [email protected]
Introduction
J. R. Kiniry e-mail: [email protected] H. W. Polley e-mail: [email protected] P. A. Fay e-mail: [email protected] H. Sanchez Central National Technology Support Center, USDA-NRCS, Fort Worth, TX, USA e-mail: [email protected]
Keywords Annual net primary production . Biomass . Biofuel . Low input high diversity . Switchgrass Abbreviations ANPP annual aboveground net primary productivity CRP Conservation Reserve Program LIHD low-input, high-diversity system
The US Departments of Agriculture (USDA) and Energy (DOE) estimate that the USA will require one billion megagrams (Mg) of biomass annually to displace 30% of current US petroleum demand with biofuels [1]. This has led to debate over how best to produce the needed plant matter, including determining optimal species, cropping systems, and appropriate land to be used for biofuel production, as well as whether biofuel mandates should exist at all [2–7]. Central to the debate is the concern that increasing our agricultural footprint thr
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