HR: 11:35h
AN: B22C-06    [Abstracts]
TI: Soil Carbon Chronosequences From Post-Agricultural Land in Western New England.
AU: * Clark, J D
EM: jclark3@sas.upenn.edu
AF: The University of Pennsylvania Earth and Environmental Science Department, 240 South 33rd Street Room 451, Philadelphia, PA 19104, United States
AU: Johnson, A H
EM: ahj@sas.upenn.edu
AF: The University of Pennsylvania Earth and Environmental Science Department, 240 South 33rd Street Room 451, Philadelphia, PA 19104, United States
AU: Richter, S
EM: richter2@sas.upenn.edu
AF: The University of Pennsylvania Earth and Environmental Science Department, 240 South 33rd Street Room 451, Philadelphia, PA 19104, United States
AU: Art, H W
EM: jclark3@sas.upenn.edu
AF: Williams College Department of Biology, Thompson Biology Laboratory 59 Lab Campus Drive Room 203, Williamstown, MA 01267, United States
AB: We used quantitatively excavated soil pits to sample chronosequences of post-agricultural northern hardwood forest soils in the Hopkins Memorial Forest, Williamstown, MA, to determine how much carbon was lost during the period of agricultural use, and the rates at which C accumulated after abandonment. We developed chronosequences (based on the time of abandonment) for the three main agricultural uses—cultivated cropland, pasture or hay, and woodlot. Active farms served as our theoretical zero time points and old-growth stands in the region served as the likely maximum. Our data show a significant direct relationship between time since abandonment and carbon amount for the organic horizons (Oe and Oa) of plots that were cultivated, hayed or pastured, but not for stands that were formerly woodlots. There was likewise a significant direct relationship between C content and time for the plowed horizons (0-10 cm) of cultivated ground, but not for the top 10 cm of mineral soils that were formerly in hay/pasture or woodlot. Our best estimates suggest that cultivation reduced the C content of plowed soils by 50% to a depth of 10 cm, and that complete recovery of the soil C pool requires about 120 years.
DE: 0428 Carbon cycling (4806)
DE: 1632 Land cover change
DE: 9350 North America
SC: Biogeosciences [B]
MN: 2007 Fall Meeting