HR: 16:00h
AN: B14A-01 INVITED     [Abstracts]
TI: Impact of Recent Land Use Changes in the Great Plains
AU: * Parton, W J
EM: billp@nrel.colostate.edu
AF: Natural Resource Ecology Laboratory, Colorado State University , Fort Collins, CO 80523-1499 United States
AU: Gutmann, M P
EM: gutmann@umich.edu
AF: The University of Michigan, Inter-University Consortium for Political and Social Research Institute for Social Research The University of Michigan PO Box 1248, Ann Arbor, MI 48106-1248 United States
AU: Ojima, D
EM: dennis@nrel.colostate.edu
AF: Natural Resource Ecology Laboratory, Colorado State University , Fort Collins, CO 80523-1499 United States
AB: During the last fifty years there has been substantial changes in agricultural land use practices and loss of agricultural land due to urbanization in the Great Plains. The major changes in land use include expansion of irrigated agriculture during the 1960's and 1970's, changes in dryland tillage practices, use of improved crop varieties, and increases in the amount of fertilizer applied to both dryland and irrigated crops. Selected regions like the Front Range of Colorado have experienced large population growth and a resulting decrease in agricultural land area and increased irrigated lawn area. The Daycent ecosystem model was used to simulate the impact of these land use changes on total system carbon and trace gas fluxes. We will highlight recent model results for the urban and rural regions in Eastern Colorado. Model results suggest that adding 4 million ha of irrigated land since the 1960's has resulted in a net carbon storage of 0.43 Tg C and a dramatic increase( 3 to 4 times higher compared to dryland agriculture ) in N2O soil emissions. Conversion agricultural land to urban lawns ( > 40000. Ha ) since the 1950's has resulted in a significant storage of carbon in the soil and a dramatic increase in NO3 leaching and N2O soil emissions ( 3 to 10 times higher compared to natural grasslands and dryland agriculture ). Results for the simulated historical changes in the net green house budgets for selected counties in Colorado will also be presented.
DE: 1630 Impact phenomena
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting