|Rotz, Clarence - Al
Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 7/23/2004
Publication Date: 10/1/2004
Citation: Corson, M.S., Rotz, C.A., Sanderson, M.A., Skinner, R.H. 2004. Simulation of warm-season grass pastures in whole-farm systems [abstract]. American Society of Agronomy Meetings. Paper No. A03-corson139-poster.
Interpretive Summary: An interpretive summary is not required.
Technical Abstract: The pasture subroutine of the Integrated Farm System Model (IFSM) was modified to simulate a warm-season grass monoculture. Predictions of grass yield and nutritive value were calibrated and evaluated with field data from switchgrass (Panicum virgatum) pastures in Pennsylvania. Sensitivity analysis showed that predicted switchgrass yield was most sensitive to physiological parameters such as proportion of photosynthate partitioned to shoots, leaf photosynthetic efficiency, specific leaf area, a light extinction coefficient, and optimal growth temperature, with sensitivity usually increasing from spring to autumn harvests. Sensitivity of yield to maximum rooting depth was greatest during periods of drought. Predicted yields at each harvest or grazing event generally were within 40% of observed values with better accuracy in predicting forage nutrient contents. The whole-farm model with a warm-season grass component provides a useful research and teaching tool for evaluating the long-term economic and environmental sustainability of dairy and beef production systems in the southeastern US and similar climactic regions of the world.