Environmental Engineering Reference
In-Depth Information
22
Switchgrass
Michael D. Casler
U.S. Department of Agriculture
Robert B. Mitchell and Kenneth P. Vogel
University of Nebraska-Lincoln
contents
22.1 Introduction ........................................................................................................................ 563
22.2 Morphology and Taxonomy ................................................................................................ 565
22.3 Genetics .............................................................................................................................. 565
22.4 Physiology and Growth ....................................................................................................... 569
22.5 Management ....................................................................................................................... 570
22.5.1 Establishment ....................................................................................................... 570
22.5.2 Fertility ................................................................................................................. 572
22.5.3 Harvest Timing and Frequency ............................................................................ 573
22.5.4 Seed Production .................................................................................................... 574
22.6 Carbon, Energy, and Economic Budgets ............................................................................ 574
22.6.1 Carbon Sequestration ........................................................................................... 574
22.6.2 Energy Balance ..................................................................................................... 575
22.6.3 Economics ............................................................................................................ 575
22.7 Breeding and Selection ....................................................................................................... 576
22.7.1 Ecotypic Variation ................................................................................................ 576
22.7.2 Breeding Methods ................................................................................................ 577
22.7.3 Breeding Objectives ............................................................................................. 580
22.7.4 Switchgrass Hybrids ............................................................................................. 581
22.7.5 Transgenic Switchgrass ........................................................................................ 582
22.7.6 DNA Marker Selection ......................................................................................... 582
22.8 Switchgrass as a Bioenergy Crop ....................................................................................... 583
References ...................................................................................................................................... 584
22.1 IntroductIon
Switchgrass (
Panicum virgatum
L.) is a tall, erect, warm-season perennial native to the tall grass
prairie, oak savanna, and associated ecosystems of North America. It can be found in prairies, open
woodlands, and brackish marshes east of the Rocky Mountains and generally south of 55° north
latitude (Hitchcock 1951; Stubbendieck et al. 1991). Less than 1% of these ecosystems exist today,
but these prairie and savanna remnants have served as in situ gene banks, preserving a vast amount
of genetic diversity within switchgrass and many other plant species. Switchgrass has a diversity
of uses as well, including pasture, hay production, biomass for energy production, soil and water
conservation, carbon sequestration, and wildlife habitat.
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