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United States Department of Agriculture

Agricultural Research Service

Title: SWITCHGRASS SIMULATION BY THE ALMANAC MODEL AT DIVERSE SITES IN THE SOUTHERN U.S.

Authors
item Kiniry, James
item Cassida, Kimberly
item Hussey, M - TEXAS A&M UNIV
item Muir, J - TEXAS AGRIC EXP STATION
item Ocumpaugh, W - TEXAS AGRIC EXP STATION
item Read, J - TEXAS AGRIC EXP STATION
item Reed, R - ANGELO STATE UNIV
item Sanderson, Matt
item Venuto, Bradley
item Williams, J - TEXAS AGRIC EXP STATION

Submitted to: Biomass and Bioenergy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 14, 2005
Publication Date: December 1, 2005
Citation: Kiniry, J.R., Cassida, K.A., Hussey, M.A., Muir, J.P., Ocumpaugh, W.R., Read, J.C., Reed, R.L., Sanderson, M.A., Venuto, B.C., Williams, J.R. 2005. Switchgrass simulation by the ALMANAC model at diverse sites in the southern US. Biomass and Bioenergy. 29(6):419-425.

Interpretive Summary: Computer simulation models for plant species important for biofuel such as switchgrass can be used to make management decisions related to plant productivity and related to environmental impacts such as soil erosion and changes in surface and groundwater quality. The present study was designed to evaluate the accuracy of simulation of switchgrass production by the ALMANAC computer simulation model at sites in Texas, Arkansas, and Louisiana. We used three to five years of field data for Alamo switchgrass yields at each of five sites to evaluate this model. The model realistically simulated mean switchgrass production at each of the locations, but did not perform as well in accounting for the year-to-year variability. Two parameters in the model, runoff curve number (CN) and maximum stomatal conductance (GSI) had variable impacts on simulated production among the sites. ALMANAC shows promise as a computer tool to realistically simulate switchgrass at these diverse sites.

Technical Abstract: Simulation models for plant species important for biofuel such as switchgrass (Panicum virgatum L.) can be used to make management decisions related to biomass productivity and related to environmental impacts such as soil erosion and changes in surface and groundwater quality. The present study was designed to evaluate the accuracy of simulation of switchgrass biomass production by the ALMANAC (Agricultural Land Management Alternatives with Numerical Assessment Criteria) model at sites in Texas, Arkansas, and Louisiana. We used multi-year field data for Alamo switchgrass yields at each of five sites to evaluate ALMANAC. The model realistically simulated mean switchgrass yields at each of the locations, but did not perform as well in accounting for the year-to-year variability. Sensitivity analysis showed that changes in runoff curve number (CN) and changes in maximum stomatal conductance (GSI) had variable impacts on simulated values among the sites. A 15% change in CN changed mean annual biomass yield from 0 to 16% depending on location. Changing GSI from 0.004 to 0.008 m s**-1 changed mean annual biomass 1 to 31% depending on location. ALMANAC shows promise as a tool to realistically simulate mean biomass yields and variability around the mean for multiyear runs of switchgrass at these diverse sites in Texas, Arkansas, and Louisiana. Further research, with more extensive measurements of soil parameters including soil nutrients is needed to determine why the model reasonably simulated individual years’ yields at Stephenville and Dallas, but had difficulty at other sites.

Last Modified: 7/10/2014
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