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ARS Home » Plains Area » Temple, Texas » Grassland Soil and Water Research Laboratory » Research » Publications at this Location » Publication #298484
Title: Modeling differential growth in switchgrass cultivars across the Central and Southern Great Plains

Author
item Behrman, Kathrine
item KEITT, TIMOTHY - University Of Texas
item Kiniry, James

Submitted to: BioEnergy Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2014
Publication Date: 11/29/2014
Publication URL: http://handle.nal.usda.gov/10113/60430
Citation: Behrman, K.D., Keitt, T.H., Kiniry, J.R. 2014. Modeling differential growth in switchgrass cultivars across the Central and Southern Great Plains. BioEnergy Research. 7(4):1165-1173.

Interpretive Summary: Switchgrass is an important biofuel crop that is adapted to a wide range of environmental and climatic conditions. Zones of adaptation for many switchgrass cultivars are well documented and attributed to local adaptation to the temperature and daylength at the locations that they originated. Our objective in this study is to develop values to describe growth of four switchgrass varieties so we can simulate them with the ALMANAC model. These values (parameters) are based on where each variety was developed. We then used these to predict production of two lowland varieties and two upland varieties in the central and southern Great Plains. Five plant parameters were adjusted to reflect the temperature and daylength at each variety’s location of origin. Average simulated and measured yields differed by less than 0.5 Mg ha-1 across all seven field locations for each cultivar. The parameters do a reasonable job of estimating the average yield of each cultivar for most of the field locations. In addition, regional simulations of the four cultivars each show realistic spatial variation in yield across the central and southern Great Plains. The parameters derived in this project for the ALMANAC model provide a tool for optimizing choice of switchgrass cultivar on different soils, in different climates, and with different management. As such, these results are valuable for future investigations modeling switchgrass production across large geographic regions.

Technical Abstract: Switchgrass (Panicum virgatum L.) has been recognized as a potential biofuel crop, because it is adapted to a wide range of environmental and climatic conditions. Zones of adaptation for many switchgrass cultivars are well documented and attributed to local adaptation to the temperature and photoperiod at the location of origin. The objective of this study is to develop cultivar-specific growth parameters for the ALMANAC model based on location of origin and use these parameters to predict the biomass production of two lowland cultivars (Alamo and Kanlow) and two upland cultivars (Blackwell and Cave-in-Rock) in the central and southern Great Plains. The plant parameters adjusted for each cultivar’s origin include: average growing season temperature, photoperiod at growth onset, maximum number of heat units, maximum leaf area index, and light extinction coefficient. The absolute difference between the average simulated and measured yields across all seven field locations for each cultivar is less than 0.5 Mg ha-1. Performance of the cultivar-specific parameters varies by location, but the parameters do a reasonable job of estimating the average yield of each cultivar for a majority of field locations. In addition, regional simulations of the four cultivars each show realistic spatial variation in yield across the central and southern Great Plains. The parameters derived in this project for the ALMANAC model provide a tool for optimizing choice of switchgrass cultivar on different soils, in different climates, and with different management. As such, these results are valuable for future investigations modeling switchgrass production across large geographic regions.