Sleuthing for drivers of particulate organic matter chemical fingerprints: Effects of land use history and soil heterogeneity in the winegrape region of Napa, CA
Abstract
Quantity and quality of soil organic matter (SOM, whole soil) and particulate organic matter (POM) fractions may reflect land use history and soil heterogeneity. Attributes of soil heterogeneity like soil mineralogy and texture serve as crucial components in stabilizing SOM, especially the fine fraction (<53 μm) associated with clay minerals. Recent advances in technology (e.g., Fourier Transform Infrared Spectroscopy, FTIR) have allowed better characterization of SOM chemical profiles, or fingerprints. Here, we investigate the combined roles of soil management, land use history and soil heterogeneity on content POM and SOM and chemical fingerprints of SOM and silt/clay-associated OM to reveal how agricultural practices influence soil carbon balance in Mediterranean climates. Soils of a winegrape growing region (Napa, California) were formed into eight clusters by Partitioning Around Medoids (PAM), using existing datasets from NRCS SoilWeb for soil great group, texture class, aspect, slope, elevation, irradiation, and soil organic matter. At least three vineyards (three locations per vineyard) of each soil cluster type were surveyed for soil attributes (pH, exchangeable cations, cation exchange capacity, texture, SOM, POM, TOC, DON; n = 72 sampled locations). The chemical fingerprints of SOM and silt/clay associated-OM (<53 μm; 0-5 cm and 5-10 cm in depth) were measured by FTIR. Current management and land use history were gathered through interviews with vineyard managers. Soil mineralogy was determined by x-ray diffraction (XRD). Data trends suggest that drivers (any natural or human-induced factor that causes a change) of the chemical fingerprints were linked to management practices and land use history, whereas content was strongly linked to soil heterogeneity and mineralogy. Using vineyards as the model system, these data establish the framework for a comprehensive study linking agricultural landscape attributes to processes directing SOM stabilization, greenhouse gas emissions, and the soil microorganisms responsible for such emissions.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.B33D0507Y
- Keywords:
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- 0402 BIOGEOSCIENCES Agricultural systems;
- 0428 BIOGEOSCIENCES Carbon cycling;
- 0400 BIOGEOSCIENCES