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ARS Home » Plains Area » Lincoln, Nebraska » Wheat, Sorghum and Forage Research » Research » Publications at this Location » Publication #237890
Title: Simulating Switchgrass Growth and Development Under Potential and Water-limiting Conditions

Author
item GRASSINI, PATRICIO - University Of Nebraska
item HUNT, ERIC - University Of Nebraska
item Mitchell, Robert - Rob
item WEISS, ALBERT - University Of Nebraska

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/5/2009
Publication Date: 4/3/2009
Citation: Grassini, P., Hunt, E., Mitchell, R., Weiss, A. Simulating Switchgrass Growth and Development Under Potential and Water-limiting Conditions. Agronomy Journal 101:564-571. 2009.

Interpretive Summary: Switchgrass is an emerging biofuel production crop, and efforts are increasing to simulate its growth and development. This study describes the structure and testing of a switchgrass growth and development model based on robust empirical relationships between plant behavior and the environment. The model simulates date for the start of regrowth, anthesis, aboveground biomass, leaf area index, and water balance components with a daily time step for crops grown under potential and water limiting conditions. Daily weather data (solar radiation, maximum and minimum temperature, and rainfall), soil available water-holding capacity, and the fraction of available water-holding capacity at the start of regrowth are required inputs. Two cultivar-specific parameters, the maximum rate of development at the optimum temperature and maximum leaf area index, are combined and demonstrate the differences in development and growth between cultivars. Tested against 10 independent data sets, the model predicted date of anthesis within 3 days and predicted aboveground biomass within about 0.7 tons acre-1. This model can be used to simulate aboveground biomass over a wide range of conditions found in the U.S. Great Plains.

Technical Abstract: Anticipating a demand for switchgrass (Panicum virgatum L.) as a source for biofuel production, a crop simulation model of this crop can be a component of a biofuel decision support system. The objective of this effort was to develop and test a model for switchgrass, based on robust empirical relationships between plant behavior and the environment. The model simulates date of annual growth initiation (AGI), anthesis, aboveground biomass, leaf area index (LAI), and water balance components with a daily time step for crops grown under potential and water- limiting conditions. Daily weather data (solar radiation, maximum and minimum temperature, and rainfall), soil available water-holding capacity (AWHC), and the fraction of AWHC at the date of AGI (FAWHC-AGI) are required inputs. Two cultivar-specific parameters, the maximum rate of development at the optimum temperature (Rmax) and maximum LAI (MAXLAI), synthesize differences in development and growth between cultivars. Tested against 10 independent data sets, the model generated good predictions of date of anthesis (root mean square error [RMSE] = 3d) and aboveground biomass (RMSE = 1.5 Mg ha–1).