Modeling Soil Organic Carbon for Agricultural Land Use Under Various Management Practices
Abstract
Bioenergy is generating tremendous interest as an alternative energy source that is both environmentally friendly and economically competitive. The amount of land designated for agriculture is expected to expand, including changes in the current distribution of crops, as demand for biofuels increases as a carbon neutral alternative fuel source. However, the influence of agriculture on the carbon cycle is complex, and varies depending on land use change and management practices. The purpose of this research is to integrate agriculture in the carbon-nitrogen based Community Land Model (CLM) to evaluate the above and below ground carbon storage for corn, soybean, and wheat crop lands. The new model, CLM-Crop simulates carbon allocation during four growth stages, a soybean nitrogen fixation scheme, fertilizer, and harvest practices. We present results from this model simulation, which includes the impact of a new dynamic roots module to simulate the changing root structure and depth with growing season based on the availability of water and nitrogen in the root zone and a retranslocation scheme to simulate redistribution of nitrogen from leaves, roots, and stems to grain during organ development for crop yields, leaf area index (LAI), carbon allocation, and changes in soil carbon budgets under various practices such as fertilizer and residue management. Simulated crop yields for corn, soybean and wheat are in general agreement with measurements. Initial model results indicate a loss of soil organic carbon over cultivated lands after removal of natural vegetation which continues in the following years. Soil carbon in crop lands is a strong function of the residue management and has the potential to impact crop yields significantly.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFM.B51F0348K
- Keywords:
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- 0402 BIOGEOSCIENCES / Agricultural systems;
- 0414 BIOGEOSCIENCES / Biogeochemical cycles;
- processes;
- and modeling;
- 0428 BIOGEOSCIENCES / Carbon cycling;
- 0466 BIOGEOSCIENCES / Modeling