51-24 Effects of Nitrogen Fertilizer On Soil Organic Matter Pools Under Switchgrass Agriculture.

Poster Number 24

See more from this Division: Agriculture and Natural Resources Science for Climate Variability and Change: Transformational Advancements in Research, Education and Extension
See more from this Session: Project Director Meeting for Agriculture and Natural Resources Science for Climate Variability and Change
Monday, October 22, 2012
Duke Energy Convention Center, Junior Ballroom D, Level 3
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Zackary P. Valdez1, William C. Hockaday1, Morgan E. Gallagher2, Caroline A. Masiello2 and Xiaodong Gao2, (1)Geology, Baylor University, Waco, TX
(2)Earth Science, Rice University, Houston, TX
The cropping of switchgrass (Panicum virgatum) for biomass shows potential for high yields in marginal lands with low fertilizer inputs, while the extensive root system can act to improve soil quality and sequester atmospheric carbon dioxide in the soil carbon pool. We are investigating the impact of nitrogen fertilizer inputs on soil organic matter quantity and quality in a biofuels cropping trial in Michigan. Here we test the hypothesis that fertilizer application rate can affect the partitioning of organic matter into different storage pools within the soil: roots, particulate organic matter (density <1.8 g/cm3), and protected organic matter (density > 1.8 g/cm3).  Additionally, we use 13C Nuclear Magnetic Resonance (NMR) spectroscopy to study the bulk chemistry (carbohydrate, lignin, lipid, and protein) of the roots and particulate soil organic matter. The NMR data also allow us to estimate the relative decomposition of the soil organic matter using a standard decomposition index (alkyl/O-alkyl peak ratio). We use these data to infer the influence of fertilizer management on the mechanisms of soil C storage and decomposition in switchgrass agriculture.
See more from this Division: Agriculture and Natural Resources Science for Climate Variability and Change: Transformational Advancements in Research, Education and Extension
See more from this Session: Project Director Meeting for Agriculture and Natural Resources Science for Climate Variability and Change