HR: 17:35h
AN: B44B-07 INVITED     [Abstracts]
TI: Incorporating representation of agricultural ecosystems and management within a dynamic biosphere model: Approach, validation, and significance
AU: * Kucharik, C
EM: kucharik@wisc.edu
AF: University of Wisconsin-Madison, 1710 University Avenue, Madison, WI 53726 United States
AB: At the scale of individual fields, crop models have long been used to examine the interactions between soils, vegetation, the atmosphere and human management, using varied levels of numerical sophistication. While previous efforts have contributed significantly towards the advancement of modeling tools, the models themselves are not typically applied across larger continental scales due to a lack of crucial data. Furthermore, many times crop models are used to study a single quantity, process, or cycle in isolation, limiting their value in considering the important tradeoffs between competing ecosystem services such as food production, water quality, and sequestered carbon. In response to the need for a more integrated agricultural modeling approach across the continental scale, an updated agricultural version of a dynamic biosphere model (IBIS) now integrates representations of land-surface physics and soil physics, canopy physiology, terrestrial carbon and nitrogen balance, crop phenology, solute transport, and farm management into a single framework. This version of the IBIS model (Agro-IBIS) uses a short 20 to 60-minute timestep to simulate the rapid exchange of energy, carbon, water, and momentum between soils, vegetative canopies, and the atmosphere. The model can be driven either by site-specific meteorological data or by gridded climate datasets. Mechanistic crop models for corn, soybean, and wheat use physiologically-based representations of leaf photosynthesis, stomatal conductance, and plant respiration. Model validation has been performed using a variety of temporal scale data collected at the following spatial scales: (1) the precision-agriculture scale (5 m), (2) the individual field experiment scale (AmeriFlux), and (3) regional and continental scales using annual USDA county-level yield data and monthly satellite (AVHRR) observations of vegetation characteristics at 0.5 degree resolution. To date, the model has been used with great success to quantify the impact of nitrogen fertilizer management and climate variability since 1950 on nitrate export in the Mississippi Basin, the consequence of historical land-cover changes in the U.S. on the hydrologic cycle, and most recently, the potential consequence of springtime warming since the 1950s on farm management and crop yields across the Corn Belt. The power of this modeling approach is that representations of the key ecological processes interact with the important drivers of environmental change including climate, atmospheric carbon dioxide, and maybe most importantly, humans.
DE: 3322 Land/atmosphere interactions
DE: 1851 Plant ecology
DE: 1615 Biogeochemical processes (4805)
DE: 1655 Water cycles (1836)
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting