HR: 1340h
AN: B43A-0141    [Abstracts]
TI: The Spatial Pattern of Soil Nutrients in a dry Tropical Forest Following Shifting Culitvation
AU: * Diekmann, L
EM: diekmann@nature.berkeley.edu
AF: University of California, Berkeley, Department of Environmental Science, Policy, and Management, 151 Hilgard Hall #3110, University of California, Berkeley, CA 94720
AU: Lawrence, D
EM: dl3c@virginia.edu
AF: University of Virginia, Department of Environmental Sciences, University of Virginia, Clark Hall, 291 McCormick Rd., Charlottesville, VA 22904
AB: The role that fallow vegetation plays in the recovery of soil nutrient concentrations is the basis of shifting cultivation, yet its role in structuring spatial patterns in the soil is not well understood. To determine the effect of shifting cultivation on the distribution of soil properties in a dry tropical forest, we intensively sampled three forest stands in El Refugio, an agricultural community in the Southern Yucatan Peninsula Region (SYRP). These sampling sites, which included a mature forest and two 8-year old secondary forests, represented a gradient of cultivation history (0-2 cycles). Using geostatistics, we characterized the degree and extent of spatial variability in P, K, Al, and organic matter content. In the mature forest, P and K were autocorrelated over a distance $>$ 6 m. In the forest fallows, where the density of small stems was greatest, P and K were autocorrelated over 1.3 to 4.8 m. Conversely, Al, which is not required by plants and is potentially toxic, was autocorrelated over similar distances (1.8 to 2.5 m) at all 3 sites. These results suggest that the spatial pattern of biologically important soil properties changes following shifting cultivation, most likely reflecting differences in the size of individual trees in stands with different cultivation histories.
DE: 1803 Anthropogenic effects
DE: 1851 Plant ecology
DE: 1615 Biogeochemical processes (4805)
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting