ENABLING MANAGEMENT RESPONSE OF SOUTHEASTERN AGRICULTURAL CROP AND PASTURE SYSTEMS TO CLIMATE CHANGE
Location: National Soil Dynamics Laboratory
Title: Strategies for carbon sequestration and reducing greenhouse gas emissions from nursery production systems
Submitted to: Technical Report
Publication Type: Research Technical Update
Publication Acceptance Date: February 24, 2011
Publication Date: February 25, 2011
Citation: Prior, S.A., Runion, G.B., Torbert III, H.A., Gilliam, C.H., Marble, S.A. 2011. Strategies for carbon sequestration and reducing greenhouse gas emissions from nursery production systems. U.S. Department of Agriculture, Agricultural Research Service (USDA-ARS), Floriculture and Nursery Research Initiative (FNRI) Progress Report. National Soil Dynamics Laboratory, Auburn, AL. p. 55.
Interpretive Summary: Over the past three decades, climate change and its potential impacts on the global environment have received significant attention from the scientific community. Increased atmospheric carbon dioxide (CO2) concentration, along with other trace gases [i.e., methane (CH4) and nitrous oxide (N2O)] are widely believed to be the driving factors behind global warming. Much of the work on reducing greenhouse gas (GHG) emissions and carbon (C) sequestration has been conducted in row crop and forest systems; however, virtually no work has focused on contributions from sectors of the specialty crop industry such as ornamental horticulture. Ornamental horticulture impacts rural, suburban, and urban landscapes. While this industry may have some negative impacts (e.g., CO2 and trace gas efflux), it also has potential to reduce GHG emissions and increase C sequestration. Priorities for this project are to determine baseline GHG emissions from common nursery production systems while also developing strategies to reduce these emissions and sequester C by altering management practices.
Currently two experiments are being conducted to determine the impact of the ornamental horticulture industry on GHG emissions and on C sequestration. One study focuses on the effect of nursery container size to begin indentifying components of the industry that may impact GHG emissions. In this study, dwarf yaupon hollies are being grown in four commonly used container sizes using standard potting media. Greenhouse gas emissions are being sampled in situ using the static, closed chamber method according to USDA’s Greenhouse Gas Reduction Through Agricultural Carbon Enhancement network (GRACEnet) protocols. Greenhouse gas emissions (CO2, CH4, N2O) are being assessed weekly and analyzed using gas chromatography. Data are currently being analyzed and processed. The second study focuses on determining techniques for increasing potential C storage in urban and suburban landscapes. This is being accomplished by evaluating different plant species and potting media and determining how these factors affect C sequestration in the landscape. The Horticulture Department at Auburn University has ongoing research to develop alternative substrates for horticulture production. This study utilizes three growth substrates: 1) Pinebark (industry standard); 2) Clean Chip Residual; and 3) Whole Tree. Twelve commonly grown woody ornamentals were grown in these differing substrates and then outplanted to the field in December, 2008. Of these twelve species, three tree species (oak, magnolia, and crape myrtle) were first selected to monitor soil C efflux and soil C content. Initial soil samples were collected in summer 2009 for determination of soil C and N on all twelve species. An Automated Carbon Efflux System (ACES) was installed adjacent to the three tree species within this study to continuously monitor C lost through soil respiration. Periodic soil samples are being taken to monitor changes in soil C, providing information on both inputs (biomass) and outputs (respiration). Preliminary results from soil C analysis and ACES system efflux data indicate that potting media and species do have significant effects on C sequestration in the landscape. In November, 2010, the three tree species were destructively harvested to determine biomass of both aboveground and root portions of the plant. These data are currently being analyzed to further investigate the role of species and media on C sequestration in the landscape. In addition, the ACES system was installed next to three additional species following the destructive harvest of the trees to determine soil C efflux from additional container ornamental species. To date, this research has resulted in two recent peer reviewed journal articles, three conference proceedings articles, and 12 presentations at regional and national scientific meetings.