Midwest Agriculture Land Cover Change Implications to North American Carbon Balance 1982-2005
Christopher
Sean
Neigh, Science Systems Applications Inc., NASA Goddard Space Flight Center,, Hydrospheric & Biospheric Sciences, Code 614.4,, neigh@gsfc.nasa.gov
(Presenting)
Nuno
Carvlhais, Department of Environmental Sciences and Engineering,, Faculty of Sciences and Technology,, New University of Lisbon, Lisbon, Portugal, nmmc@fct.unl.pt
G.
Jim
Collatz, NASA Goddard Space Flight Center,, Hydrospheric & Biospheric Sciences, Code 614.4,, jcollatz@biome2.gsfc.nasa.gov
Compton
Jim
Tucker, NASA Goddard Space Flight Center,, Hydrospheric & Biospheric Sciences, Code 614.4,, compton@ltpmail.gsfc.nasa.gov
A coupled assessment of land-cover land-use change was undertaken integrating GeoCover Landsat remote sensing observations in process based biogeochemistry simulations to quantify regional changes in agriculture productivity practices in accounting for net ecosystem carbon balance from 1982 to 2005. Two regional sites were selected from a record of Normalized Difference Vegetation Index Global Inventory Mapping and Modeling Studies version ‘g’ which had marked increases in vegetation production from 1982-2005. Harvest, irrigation, and no-tillage of the soil was integrated into Carnegie-Ames-Stanford Approach (CASA) simulations with changing fractional agriculture area derived from Landsat to assess importance of fine-scale land-use practices on regional carbon balance. Two distinct dynamics were found: 1) Southern Saskatchewan had post drought rain-fed agriculture recovery; 2) Oklahoma Panhandle had expansion of irrigated agriculture. Both observations predicted sinks of carbon due to harvest while reducing detritus input to the soil reducing heterotrophic respiration flux. Simulations results were compared to U.S. Department of Agriculture, national agriculture production statistics records to validate model predictions. Limitations to net ecosystem simulations were found in which important processes that capture regional carbon cycle balance were excluded as found herein. Calculation of net biome production is critical in regions with extensification or intensification of irrigation, no-till and harvest with regional increases of >250 terragrams of carbon which may not be accounted for otherwise.
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