Spatial variability of soil organic carbon in grasslands: implications for detecting change at different scales.
Extensive data used to quantify broad soil C changes (without information about causation), coupled with intensive data used for attribution of changes to specific management practices, could form the basis of an efficient national grassland soil C monitoring network. Based on variability of extensive (USDA/NRCS pedon database) and intensive field-level soil C data, we evaluated the efficacy of future sample collection to detect changes in soil C in grasslands. Potential soil C changes at a range of spatial scales related to changes in grassland management can be verified (alpha=0.1) after 5 years with collection of 34, 224, 501 samples at the county, state, or national scales, respectively. Farm-level analysis indicates that equivalent numbers of cores and distinct groups of cores (microplots) results in lowest soil C coefficients of variation for a variety of ecosystems. Our results suggest that grassland soil C changes can be precisely quantified using current technology at scales ranging from farms to the entire nation.
Conant
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Natural Resource Ecology Laboratory, Colorado State University, Fort Collins 80523-1499, USA. conant@nrel.colostate.edu
Paustian
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D002244:Carbon / Q000032:analysis / Q000378:metabolism*; D016208:Databases, Factual; D017753:Ecosystem; D004784:Environmental Monitoring; D009930:Organic Chemicals / Q000032:analysis; D006109:Poaceae; D012987:Soil
D009930:Organic Chemicals; D012987:Soil; D002244:Carbon