Distribution, accumulation, and fluxes of soil carbon in four monoculture lysimeters at San Dimas Experimental Forest, California

摘要: Abstract This research examines how vegetation type controls soil processes involving carbon fluxes, accumulation, and transport in a chaparral ecosystem. Carbon concentrations δ13C values were measured for samples collected 1987 from 1-m depth profiles four lysimeters the San Dimas Experimental Forest, southern California, USA. Each lysimeter has sustained single since 1946, species being Quercus dumosa, Ceanothus crassifolius, Adenostoma fasciculatum, Pinus coulteri. Archived of originally used filling litter surface each analyzed to determine initial boundary conditions. Although detectable changes content limited topmost 20 cm profiles, variations found depths 80 cm, indicating that processing occurs much deeper than indicated by alone, underscoring utility isotopes study dynamics. A one-dimensional model considers input, downward transport, loss through decomposition is developed describe evolution concentration stable isotope ratios profiles. Comparison calculated yields estimates turnover rates, accumulation carbon. set physical parameters, including rate constant decomposition, organic carbon, input are derived can be related environmental The calculations indicate importance on formation cycles, which important understanding effects land use ecosystem processes. Our results also suggest fire may increase