Switchgrass is being widely considered as a feedstock for biofuel production. Much remains to be ... more Switchgrass is being widely considered as a feedstock for biofuel production. Much remains to be learned about ideal feedstock characteristics, but switchgrass offers many advantages already and can perhaps be manipulated to offer more. When planning to grow switchgrass, select a cultivar that is well adapted to the location - generally a lowland cultivar for the southern United States and an upland cultivar at higher latitudes. Plant non-dormant seed after soils are well warmed, preferably with no-till methods and always with good weed control. Except for weeds, few pests appear to be widespread; but disease and insect pests could become more important as acreages increase. Fertilization requirements are relatively low, with 50 kg N/ha/year being a good "generic" recommendation where a single harvest is taken after plants have senesced; more will be needed if biomass is harvested while still green. Switchgrass should be harvested no more than twice per year and may generally be expected to produce 12 to >or=20 mg/ha/year across its usual range of distribution. A single harvest may provide for maximum sustainable yields - especially if the harvest is taken after tops die back at the end of the season. Several harvesting technologies are available, but the preferred technology may depend on logistics and economics associated with the local processing point, or biorefinery.
Sustainable development of a bioenergy industry will require low-cost, high-yielding biomass feed... more Sustainable development of a bioenergy industry will require low-cost, high-yielding biomass feedstock of desirable quality. Switchgrass (Panicum virgatum L.) is one of the primary feedstock candidates in North America, but the potential to grow this biomass crop using fertility from biosolids has not been fully explored. The objective of this study was to examine the effects of harvest frequency and biosolids application on switchgrass in Virginia, USA. 'Cave-in-Rock' switchgrass from well-established plots was cut once (November) or twice (July and November) per year between 2010 and 2012. Class A biosolids were applied once at rates of 0, 153, 306, and 459 kg N ha À1 in May 2010. Biomass yield, neutral and acid detergent fiber, cellulose, hemicellulose, lignin, and ash were determined. Theoretical ethanol potential (TEP, l ethanol Mg À1 biomass) and yield (TEY, l ethanol ha À1 ) were calculated based on cellulose and hemicellulose concentrations. Cutting twice per season produced greater biomass yields than one cutting (11.7 vs. 9.8 Mg ha À1 ) in 2011, but no differences were observed in other years. Cutting once produced feedstock with greater TEP (478 vs. 438 l Mg À1 ), but no differences in TEY between cutting frequencies. Biosolids applied at 153, 306, and 459 kg N ha À1 increased biomass yields by 25%, 37%, and 46%, and TEY by 25%, 34%, and 42%, respectively. Biosolids had inconsistent effects on feedstock quality and TEP. A single, end-of-season harvest likely will be preferred based on apparent advantages in feedstock quality. Biosolids can serve as an effective alternative to N fertilizer in switchgrass-to-energy systems.
Corn (Zea mays L.) production recommendations should be periodically evaluated to ensure that pro... more Corn (Zea mays L.) production recommendations should be periodically evaluated to ensure that production practices remain in step with genetic improvements. Since most of the recent increases in corn grain yield are due to planting at higher densities and not to increased ...
Switchgrass ( Panicum virgatum L.)a perennial, warm-season (C 4 ) speciesevolved across North A... more Switchgrass ( Panicum virgatum L.)a perennial, warm-season (C 4 ) speciesevolved across North America into multiple, divergent populations. The resulting natural variation within the species presents considerable morphological diversity and a wide range of adaptation. The ...
AbstractÐIncreased atmospheric CO 2 , caused partly by burning fossil fuels, is assumed to elevat... more AbstractÐIncreased atmospheric CO 2 , caused partly by burning fossil fuels, is assumed to elevate the risk of global warming, while nitrate contamination of surface runo and groundwater from fertilizer and agricultural wastes constitutes a serious environmental hazard on a regional scale. Switchgrass (Panicum virgatum L.) grown as an energy crop could reduce atmospheric CO 2 accumulation by replacing fossil fuels and sequestering C. It could also improve soil productivity by C sequestration, and reduce xy À1 3 contamination of water by absorbing N lost from fertilizer and agricultural waste if planted in ®lter strips on adjacent land. The objective of this study was to assess potential impacts of switchgrass on C and N balances by reviewing and synthesizing information from current literature, unpublished data and on-going research. Replacing fossil fuels with switchgrass, or any other biomass, will have a much greater eect on atmospheric CO 2 than C sequestration. This is because replacing fossil fuels provides a cumulative eect, while C sequestration oers only a one-time bene®t. Furthermore, switchgrass will provide net gains in C sequestration only if it replaces annual row crops, but not if it replaces grazed pasture. Nitrogen recovery by switchgrass in an Alabama study was 65.6%, which compares favorably with the 50% recovery frequently quoted as the norm for wheat (Triticum aestivum L.) and corn (Zea mays L). #
Limited information is available regarding biomass production potential of long-term (45-yr-old) ... more Limited information is available regarding biomass production potential of long-term (45-yr-old) switchgrass (Panicum virgatum L.) stands. Variables of interest in biomass production systems include cultivar selection, site/environment effects, and the impacts of fertility and harvest management on productivity and stand life. We studied biomass production of two upland and two lowland cultivars under two different managements at eight sites in the upper southeastern USA during 1999-2001. (Sites had been planted in 1992 and continuously managed for biomass production.) Switchgrass plots under lower-input management received 50 kg N ha À1 yr À1 and were harvested once, at the end of the season. Plots under higher-input management received 100 kg N ha À1 (in two applications) and were harvested twice, in midsummer and at the end of the season. Management effects on yield, N removal, and stand density were evaluated. Annual biomass production across years, sites, cultivars, and managements averaged 14.2 Mg ha À1 . Across years and sites, a large (28%) yield response to increased inputs was observed for upland cultivars; but the potential value of higher-input management for lowland cultivars was masked overall by large site  management interactions. Nitrogen removal was greater under the higher-input system largely due to greater N concentrations in the midsummer harvests. Management recommendations (cultivar, fertilization, and harvest frequency), ideally, should be site and cultivar dependent, given the variable responses reported here. r
1974), Prunus (Haut, 1932), Polygonum spp. (Justice, 1944; Staniforth and Cavers, 1979), Pyrus sp... more 1974), Prunus (Haut, 1932), Polygonum spp. (Justice, 1944; Staniforth and Cavers, 1979), Pyrus spp. (West-Switchgrass (Panicum virgatum L.) seed dormancy is a major wood and Bjornstad, 1968), and Pinus taeda L. (Barnett, obstacle to successful establishment of this multi-purpose species. We have investigated the influences of prolonged stratification, poststrati-1972). By contrast, partial drying of dormant (freshly fication drying, restratification, and afterripening on germinability of harvested) or partly dormant (stratified for 1 mo) seeds 'Cave-in-Rock' switchgrass seeds. Germination can be increased manyof Zizania palustris L. increased subsequent germinafold to Ն80% with 14 d of stratification, if the seeds are moved directly Abbreviations: MC, moisture content. Published in Crop Sci. 41:1546-1551 (2001).
Switchgrass is being widely considered as a feedstock for biofuel production. Much remains to be ... more Switchgrass is being widely considered as a feedstock for biofuel production. Much remains to be learned about ideal feedstock characteristics, but switchgrass offers many advantages already and can perhaps be manipulated to offer more. When planning to grow switchgrass, select a cultivar that is well adapted to the location - generally a lowland cultivar for the southern United States and an upland cultivar at higher latitudes. Plant non-dormant seed after soils are well warmed, preferably with no-till methods and always with good weed control. Except for weeds, few pests appear to be widespread; but disease and insect pests could become more important as acreages increase. Fertilization requirements are relatively low, with 50 kg N/ha/year being a good "generic" recommendation where a single harvest is taken after plants have senesced; more will be needed if biomass is harvested while still green. Switchgrass should be harvested no more than twice per year and may generally be expected to produce 12 to >or=20 mg/ha/year across its usual range of distribution. A single harvest may provide for maximum sustainable yields - especially if the harvest is taken after tops die back at the end of the season. Several harvesting technologies are available, but the preferred technology may depend on logistics and economics associated with the local processing point, or biorefinery.
Sustainable development of a bioenergy industry will require low-cost, high-yielding biomass feed... more Sustainable development of a bioenergy industry will require low-cost, high-yielding biomass feedstock of desirable quality. Switchgrass (Panicum virgatum L.) is one of the primary feedstock candidates in North America, but the potential to grow this biomass crop using fertility from biosolids has not been fully explored. The objective of this study was to examine the effects of harvest frequency and biosolids application on switchgrass in Virginia, USA. 'Cave-in-Rock' switchgrass from well-established plots was cut once (November) or twice (July and November) per year between 2010 and 2012. Class A biosolids were applied once at rates of 0, 153, 306, and 459 kg N ha À1 in May 2010. Biomass yield, neutral and acid detergent fiber, cellulose, hemicellulose, lignin, and ash were determined. Theoretical ethanol potential (TEP, l ethanol Mg À1 biomass) and yield (TEY, l ethanol ha À1 ) were calculated based on cellulose and hemicellulose concentrations. Cutting twice per season produced greater biomass yields than one cutting (11.7 vs. 9.8 Mg ha À1 ) in 2011, but no differences were observed in other years. Cutting once produced feedstock with greater TEP (478 vs. 438 l Mg À1 ), but no differences in TEY between cutting frequencies. Biosolids applied at 153, 306, and 459 kg N ha À1 increased biomass yields by 25%, 37%, and 46%, and TEY by 25%, 34%, and 42%, respectively. Biosolids had inconsistent effects on feedstock quality and TEP. A single, end-of-season harvest likely will be preferred based on apparent advantages in feedstock quality. Biosolids can serve as an effective alternative to N fertilizer in switchgrass-to-energy systems.
Corn (Zea mays L.) production recommendations should be periodically evaluated to ensure that pro... more Corn (Zea mays L.) production recommendations should be periodically evaluated to ensure that production practices remain in step with genetic improvements. Since most of the recent increases in corn grain yield are due to planting at higher densities and not to increased ...
Switchgrass ( Panicum virgatum L.)a perennial, warm-season (C 4 ) speciesevolved across North A... more Switchgrass ( Panicum virgatum L.)a perennial, warm-season (C 4 ) speciesevolved across North America into multiple, divergent populations. The resulting natural variation within the species presents considerable morphological diversity and a wide range of adaptation. The ...
AbstractÐIncreased atmospheric CO 2 , caused partly by burning fossil fuels, is assumed to elevat... more AbstractÐIncreased atmospheric CO 2 , caused partly by burning fossil fuels, is assumed to elevate the risk of global warming, while nitrate contamination of surface runo and groundwater from fertilizer and agricultural wastes constitutes a serious environmental hazard on a regional scale. Switchgrass (Panicum virgatum L.) grown as an energy crop could reduce atmospheric CO 2 accumulation by replacing fossil fuels and sequestering C. It could also improve soil productivity by C sequestration, and reduce xy À1 3 contamination of water by absorbing N lost from fertilizer and agricultural waste if planted in ®lter strips on adjacent land. The objective of this study was to assess potential impacts of switchgrass on C and N balances by reviewing and synthesizing information from current literature, unpublished data and on-going research. Replacing fossil fuels with switchgrass, or any other biomass, will have a much greater eect on atmospheric CO 2 than C sequestration. This is because replacing fossil fuels provides a cumulative eect, while C sequestration oers only a one-time bene®t. Furthermore, switchgrass will provide net gains in C sequestration only if it replaces annual row crops, but not if it replaces grazed pasture. Nitrogen recovery by switchgrass in an Alabama study was 65.6%, which compares favorably with the 50% recovery frequently quoted as the norm for wheat (Triticum aestivum L.) and corn (Zea mays L). #
Limited information is available regarding biomass production potential of long-term (45-yr-old) ... more Limited information is available regarding biomass production potential of long-term (45-yr-old) switchgrass (Panicum virgatum L.) stands. Variables of interest in biomass production systems include cultivar selection, site/environment effects, and the impacts of fertility and harvest management on productivity and stand life. We studied biomass production of two upland and two lowland cultivars under two different managements at eight sites in the upper southeastern USA during 1999-2001. (Sites had been planted in 1992 and continuously managed for biomass production.) Switchgrass plots under lower-input management received 50 kg N ha À1 yr À1 and were harvested once, at the end of the season. Plots under higher-input management received 100 kg N ha À1 (in two applications) and were harvested twice, in midsummer and at the end of the season. Management effects on yield, N removal, and stand density were evaluated. Annual biomass production across years, sites, cultivars, and managements averaged 14.2 Mg ha À1 . Across years and sites, a large (28%) yield response to increased inputs was observed for upland cultivars; but the potential value of higher-input management for lowland cultivars was masked overall by large site  management interactions. Nitrogen removal was greater under the higher-input system largely due to greater N concentrations in the midsummer harvests. Management recommendations (cultivar, fertilization, and harvest frequency), ideally, should be site and cultivar dependent, given the variable responses reported here. r
1974), Prunus (Haut, 1932), Polygonum spp. (Justice, 1944; Staniforth and Cavers, 1979), Pyrus sp... more 1974), Prunus (Haut, 1932), Polygonum spp. (Justice, 1944; Staniforth and Cavers, 1979), Pyrus spp. (West-Switchgrass (Panicum virgatum L.) seed dormancy is a major wood and Bjornstad, 1968), and Pinus taeda L. (Barnett, obstacle to successful establishment of this multi-purpose species. We have investigated the influences of prolonged stratification, poststrati-1972). By contrast, partial drying of dormant (freshly fication drying, restratification, and afterripening on germinability of harvested) or partly dormant (stratified for 1 mo) seeds 'Cave-in-Rock' switchgrass seeds. Germination can be increased manyof Zizania palustris L. increased subsequent germinafold to Ն80% with 14 d of stratification, if the seeds are moved directly Abbreviations: MC, moisture content. Published in Crop Sci. 41:1546-1551 (2001).
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