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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOPMENT OF MODELS AND CONSERVATION PRACTICES FOR WATER QUALITY MANAGEMENT AND RESOURCE ASSESSMENTS Title: Spatial forecasting of switchgrass productivity under current and future climate change scenarios

Authors
item Behrman, Kathrine -
item Kiniry, James
item Winchell, Michael -
item Juenger, Thomas -
item Keitt, Timothy -

Submitted to: Ecological Applications
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 17, 2012
Publication Date: January 21, 2013
Citation: Behrman, K.D., Kiniry, J.R., Winchell, M., Juenger, T.E., Keitt, T.H. 2013. Spatial forecasting of switchgrass productivity under current and future climate change scenarios. Ecological Applications. 23(1):73-85.

Interpretive Summary: Evaluating the potential of alternative energy crops across large geographic regions and over time is necessary to determine if feedstock production is feasible and sustainable in the face of growing production demands and climatic change. Switchgrass, a perennial grass, is a promising candidate for biofuel. ALMANAC a process-based computer simulation model that simulates growth over time has been modified for some representative switchgrass varieties and used to realistically simulate switchgrass yields in 11 states. In this study, we show how ALMANAC can be used to forecast the current and future productivity of switchgrass across the central and eastern U.S. under predicted climate change scenarios. Our results reveal that there is substantial variation in switchgrass yield within regions and over time. Areas that currently have and maintain high yields under both two future climate scenarios should be targeted for long-term growth of switchgrass to minimize land conversion and loss of biodiversity. Florida and the Texas and Louisiana Gulf Coasts have the highest long-term productivity potential but contain critical habitat for biodiversity. Marginal agricultural lands in the Northern Great Plains have variable yields under current climate conditions, but are expected to experience large increases in productivity with climate change. In general, regions where future temperature and precipitation are predicted to increase, larger future yields are expected. Whereas, regions that experience a future decrease in precipitation produce smaller yields. Climate alone does not explain all future yields. For example, future increases in temperature and precipitation for the interior southeast are not expected to have a large effect on yield. Other factors, such as nutrient limitations or soil texture, may be the limiting factor in these regions.

Technical Abstract: Evaluating the potential of alternative energy crops across large geographic regions and over time is necessary to determine if feedstock production is feasible and sustainable in the face of growing production demands and climatic change. Panicum virgatum L., a perennial herbaceous grass, is a promising candidate for cellulosic feedstock production. ALMANAC, a mechanistic model that simulates growth over time, has been parameterized for some representative ecotypes of switchgrass and used to realistically simulate switchgrass yields in 11 states. In this study, we show how ALMANAC can be used to forecast the current and future productivity of switchgrass across the central and eastern U.S. under predicted climate change scenarios. Our results reveal that there is substantial variation in switchgrass yield within regions and over time. Areas that currently have and maintain high yields under both the A2 and B2 future climate scenarios should be targeted for long-term growth of switchgrass to minimize land conversion and loss of biodiversity. Florida and the Texas and Louisiana Gulf coasts have the highest long-term productivity potential but contain critical habitat for biodiversity. Marginal agricultural lands in the Northern Great Plains have variable yields under current climate conditions, but are expected to experience large increases in productivity with climate change. In general, regions where future temperature and precipitation are predicted to increase, larger future yields are expected. Whereas, regions that experience a future decrease in precipitation produce smaller yields. Climate alone does not explain all future yields. For example, future increases in temperature and precipitation for the interior southeast are not expected to have a large effect on yield. Other factors, such as nutrient limitations or soil texture, may be the limiting factor in these regions.

Last Modified: 11/26/2014
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