Biogeochemical Cycling of Calcium and Magnesium by Ceanothus and Chamise

摘要: Vegetation has long been recognized as a fundamental factor in soil formation, but vegetation and soils commonly covary response to other environmental factors, confounding the specific effects of on properties. The lysimeter installation at San Dimas Experimental Forest southern California offers rarely found opportunity for quantifying cation-cycling processes setting where all factors except are kept constant. lysimeters were filled 1937 with homogenized, fine sandy loam planted 1946 chamise (Adenostoma fasciculatum Hook, Arn.) ceanothus (Ceanothus crassifolius Torr.). Comparison was best achieved by using Ca/Mg ration different cation pools fluxes an index. In 1987, exchangeable pool contained proportionally more Ca than Mg compared chamise; that is, ratio higher chamise. Strong evidence supports influence intra-system (weathering biocycling) basis these differences. First, released weathering under Second, aboveground biomass exhibited Third, differences between types widenedmore » time since construction both pools. Differences storage measured stands appear representative natural chaparral communities throughout California, may result distinct biogeochemical associated ecosystems.« less