Download or read book Impact of Switchgrass Bioenergy Feedstock Production on Soil Carbon Dioxide Flux and Below Ground Soil Organic Carbon Storage in East Tennessee written by Leah Denise Soro and published by . This book was released on 2011 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bioenergy production from switchgrass has shown promise in restoring degraded soils and helping to mitigate greenhouse gas (GHG) emissions. CO2 loss and C-sequestration in soils are important topics for research to better understand the environmental impacts of bioenergy crops. The need for more thorough research of the carbon cycle in soils used for bioenergy production precipitated the primary interest of this study. The specific objectives of this study were 1) to measure SOC under switchgrass production in order to predict storage of carbon in soils based on previous cropping history, land management, soil physical characteristics, and time; and to 2) measure soil CO2 flux through the entire year to establish a) the annual, seasonal, and daily respiration rates, and b) use this data with soil carbon data to better understand the carbon life cycle in soils under switchgrass production in East Tennessee. Chapter 1 of the study was conducted on twelve farms across East Tennessee. Seven previous different cropping systems, four soil textural classes, and four soil taxonomy classes are represented in this study. There was an increase in SOC of roughly 1 Mg ha−1 from 2008 to 2011. No-till planting resulted in a significant increase in SOC compared to conventional tillage planting resulting in no significant changes in SOC. Chapter 2 results as hypothesized, soil temperature and moisture had a significant influence on CO2 flux variance. Soil temperature and soil moisture were able to explain 83% and 81.5% of variance in flux from clumps (cover) and between clumps (bare) respectively. The summer months exhibited the highest flux rate followed by spring, fall, and finally winter. Although largely overlooked in previous research, the winter months did contribute 5.4 MgCO2 ha−1 season−1 (±2.5 MgCO2 ha−1 season−1) from clumps (cover) and 4.0 MgCO2 ha−1 season−1 (±3.2 MgCO2 ha−1 season−1) from between clumps (bare). Annual switchgrass flux rate was 7.39 MgCO2 ha−1 (±4.08 MgCO2 ha−1).
Download or read book Economic and Environmental Optimization in the Supply of Switchgrass in Tennessee written by Jia Zhong and published by . This book was released on 2015 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: The low efficiency of collection, storage and transportation in the switchgrass supply chain has hindered the commercialization of a switchgrass-based biofuel industry, even given its ecological and environmental advantages in carbon sequestrate, soil quality, water use, and pollution pressure. Thus, designing a switchgrass-based supply chain balancing both environmental and economic performance is important to expedite the development of the cellulosic biofuel industry to meet the national energy plan. The objectives of this study are to 1) determine economic cost and multiple environmental outcomes in feedstock supply chains and 2) identify the relation between the economic and environmental performances. The first paper considers three objectives: minimization of economic cost, greenhouse gas (GHG) emissions, and soil erosions. The second paper focuses on the relation between economic cost and abated greywater footprint for industrialized supply of cellulosic biofuel in west Tennessee. The improved augmented epsilon method and compromise solution method were applied to high-resolution spatial data to determine the optimal placement of the feedstock supply chains. Results in the first paper indicated that land change into switchgrass production is crucial to both plant-gate cost and environmental impact of feedstock supply. Converting croplands to switchgrass incurred higher opportunity cost from land use change but stored more soil carbon and generated less soil erosion. Tradeoffs in higher feedstock costs with lower GHG emissions and lower soil erosion on the frontier were captured. Soil erosion was found more cost effective criterion than GHG emission in general. The compromise solution location for the conversion facility generated at 63% increase in feedstock cost but improved the environmental impact in lowering 27 % GHG emission and decreasing soil erosion by 70 times lower in the feedstock supply chain compared with cost minimization location. Results in the second paper showed that tradeoff between feedstock costs and greywater footprint was mainly associated with the changes of land use, while ambient water quality condition was also influential to the selection of feedstock production area. The average imputed cost of lowering grey water footprint in the most preferred feedstock supply chain in west Tennessee was $0.94 m−3 [per cubic meter].
Download or read book Switchgrass Cultivar and Intraspecific Diversity Impacts on Nitrogen Use Efficiency written by Aislinn Johns and published by . This book was released on 2016 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Bioenergy feedstock production is an important component of the national renewable energy strategy, which is based on biomass supply. Biofuels for ethanol production may be produced in high-input crop production systems, but the efficacy of these systems for increasing net energy yields over its full life-cycle compared to traditional fuels is under debate, because it is now evident that the benefits of feedstock production are maximized only when biofuels are derived from feedstocks produced with much lower life-cycle greenhouse-gas emissions than traditional fossil fuels. To this end, the reduction of agricultural inputs is key to developing an effective biofuel feedstock crop. Native prairie grasses have low-input production requirements, and upon land conversion for biofuel production they have positive impacts on belowground carbon (C) sequestration, a measure of soil quality. Specifically, Panicum virgatum (hereafter switchgrass), a perennial C4 grass native to the mid-west of the United States, is a promising bioenergy crop. It has large root systems, which allow it to produce large amounts of biomass with less water and nutrient requirements than traditional bioenergy crops, such as corn. To produce switchgrass feedstock in an environmentally sustainably manner (i.e., with the least amount of fertilizer inputs), we will need to adopt agricultural practices that promote N cycling efficiency in the system. Previous studies have found that different cultivars of switchgrass vary significantly in specific root length (SRL), and greater SRL may be linked to greater N acquisition owing to the root systems' greater surface area. In addition, it has been found that growing switchgrass in genotypically diverse mixtures enhanced biomass production, which may result from belowground niche differentiation and complementarity effects that enhance N acquisition. With this study, I aimed to evaluate (1) whether differences in the architecture among root systems of switchgrass cultivars led to differences in the efficiency of nitrogen uptake, and (2) whether growing switchgrass cultivars in diverse mixtures would enhance the efficiency of nitrogen cycling though niche differentiation and complementarity effects. Our experiment was conducted at the Sustainable Bioenergy Crop Research Facility at the Fermilab National Environmental Research Park, where experimental field plots consisted of seven switchgrass cultivars, planted either in monoculture or in diverse mixtures of 2, 4, or 6 randomly selected cultivars. To evaluate differences in nitrogen use efficiency (NUE) among cultivars in monocultures and among diversity treatments, I applied a stable isotope 15N tracer at the beginning of the growing season. Following senescence, the switchgrass was harvested and the percent of 15N recovered was measured in the aboveground biomass to determine NUE. I found that switchgrass cultivars differed in NUE and these differences could potentially be linked to germplasm origin in relation to the field site. I also found that NUE was not influenced by increases in cultivar diversity. Our results suggest that NUE is not the sole mechanism behind greater biomass production associated with enhanced diversity."--Boise State University ScholarWorks.
Download or read book Switchgrass Solution written by Morgan Ann Noland and published by . This book was released on 2013 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: It has been suggested that native prairie species such as switchgrass (Panicum virgatum) can provide a sustainable, low-input biofuel feedstock, while at the same time sequestering large amounts of soil carbon. Perhaps the most sustainable approach in producing carbon-negative bioenergy utilizes mixed-species perennial ecosystems. Previous studies on restored prairie communities indicate that long-term yields can be greater with higher plant diversity than with low diversity communities or monocultures. In addition, diverse grassland plantings can provide habitat for beneficial invertebrates and wildlife. We tested our hypothesis that low-input cultivation utilizing intra- and inter-specific diversity reduces fertilizer input and nutrient leaching while providing above- and belowground ecosystem services such as wildlife habitat, aggregate stability, and increased soil carbon. Specifically, our study assessed arbuscular mycorrhizal (AM) hyphal abundance, soil carbon, aggregate stability, and above- and belowground biomass production in established plots at Argonne National Laboratory, Batavia, Illinois. Our study included monocultures of three different switchgrass cultivars, inter-cropping of these three cultivars (intra-specific diversity), and combinations of switchgrass and native prairie species (inter-specific diversity). Annual productivity of extra-radical AM hyphae was assessed using hyphal in-growth bags. Phospholipid fatty acid analyses determined total soil microbial community composition and total AM fungal biomass. Our data indicate aboveground biomass production of the switchgrass cultivar cave-in-rock, was significantly greater than southlow, big bluestem/switchgrass mix, or the diverse prairie mix. Soil from the prairie mix had significantly greater aggregate stability than all other treatments, except switchgrass mix or kanlow monocultures. However, no differences were found among extra-radical hyphal production, total microbial biomass, total AM fungal biomass, or belowground biomass. Overall, our study indicates that intra- or inter-specific feedstock production can decrease fertilizer inputs while improving aboveground ecosystem services, with no loss in belowground services.
Download or read book Plant Diversity and Nitrogen Addition on Belowground Biodiversity and Soil Organic Carbon Storage in Biofuel Cropping Systems written by Jennifer Butt and published by . This book was released on 2020 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Bioenergy production may reduce the emission of CO2 which contributes to climate change, particularly when management strategies are adopted that promote soil carbon (C) sequestration in bioenergy cropping systems. Planting perennial native grasses, such as switchgrass (Panicum virgatum L.) and big bluestem (Andropogon gerardii Vitman) may be used as a strategy to enhance soil C accumulation owing to their extensive root systems. Fertilizer use may further promote soil C sequestration, because of its positive impacts on plant production and soil C input. However, the influence of fertilizer addition on soil C accumulation is variable across bioenergy cropping systems, and fertilizer can negatively impact the environment. Increasing plant diversity may be used as a strategy to enhance soil C accumulation while augmenting other ecosystem properties such as soil biodiversity. The present study evaluates how inter- and intra- specific plant community diversity and N addition influence soil C storage and soil biodiversity. Soil was collected from a long-term (9 growing seasons) field experiment located at the Fermilab National Environmental Research Park in Illinois, USA. Treatments included [1] three cultivars of big bluestem and three cultivars of switchgrass cultivars grown in monoculture, [2] plant community diversity manipulated at both the species- and cultivar level, and [3] nitrogen (N) applied annually at two levels (0 and 67 kg ha-1). The soil at the site was dominated by C3 grasses for 30 years before replacement with C4 bioenergy grasses, which enabled quantification of plant-derived C accumulation owing to the natural difference in isotopic signature between C3 and C4 grasses. Soil samples were analyzed for [1] soil C and its delta13C isotopic signature, and [2] nematode and soil bacterial diversity. Our results indicate that both plant diversity and N addition influence soil community structure but not soil C storage or soil nematode biodiversity. However, the addition of big bluestem to the plant species mixes enhanced plant-derived C storage. In summary, our findings suggest that plant species identity can control soil C accumulation in the years following land conversion, and that manipulating plant community structure in bioenergy cropping systems may have a greater positive impact on soil C accumulation than N fertilization."--Boise State University ScholarWorks.
Download or read book Economic Analysis of Delivering Switchgrass to a Biorefinery from Both the Farmers and Processor s Perspectives written by and published by . This book was released on 2009 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: Switchgrass for bioenergy production will require substantial storage. The first paper evaluates costs of various baling and on-farm storage systems by simulating the final delivered costs to the biorefinery under two representative soil types in East Tennessee and West Tennessee. Influences of the volatilities of switchgrass yield, diesel fuel price and nitrogen fertilizer price on delivered costs are considered. Results show that rectangular bales minimize cost if switchgrass is processed immediately after harvest. However, round bales minimize cost if switchgrass is stored without protection for 200 days before being transported to the biorefinery. The second paper evaluates from the processors' perspective the least cost delivery schedule for switchgrass to a biorefinery considering bale types and storage methods. A mixed integer programming model was used to optimize the year round switchgrass delivery schedule within 50 miles of the biorefinery in East Tennessee from the processors' perspective, while minimizing the annual costs of delivering switchgrass. The delivery is constrained by land availability, switchgrass yields, field days for harvest, and storage dry matter loss. Scenario analyses for different plant sizes, harvesting systems, existence of storage loss and equipment efficiency were done in this study. Results from the base model show that the delivered cost, which accounts for $0.73/gallon of ethanol produced, is almost twice the U.S. Department of Energy's National Renewable Energy Laboratory's goal for feedstock production in 2012.
Download or read book Switchgrass written by Andrea Monti and published by Springer Science & Business Media. This book was released on 2012-03-14 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: The demand for renewable energies from biomass is growing steadily as policies are enacted to encourage such development and as industry increasingly sees an opportunity to develop bio-energy enterprises. Recent policy changes in the EU, USA and other countries are spurring interest in the cultivation of energy crops such as switchgrass. Switchgrass has gained and early lead in the race to find a biomass feedstock for energy production (and for the almost requisite need for bio-based products from such feedstocks). Switchgrass: A Valuable Biomass Crop for Energy provides a comprehensive guide to the biology, physiology, breeding, culture and conversion of switchgrass as well as highlighting various environmental, economic and social benefits. Considering this potential energy source, Switchgrass: A Valuable Biomass Crop for Energy brings together chapters from a range of experts in the field, including a foreword from Kenneth P. Vogel, to collect and present the environmental benefits and characteristics of this a crop with the potential to mitigate the risks of global warming by replacing fossil fuels. Including clear figures and tables to support discussions, Switchgrass: A Valuable Biomass Crop for Energy provides a solid reference for anyone with interest or investment in the development of bioenergy; researchers, policy makers and stakeholders will find this a key resource.
Download or read book Carbon Dioxide Emissions from Switchgrass and Cottonwood Grown as Bioenergy Crops in the Lower Mississippi Alluvial Valley written by Michele Lea Helton and published by . This book was released on 2014 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marginal land of the Lower Mississippi Alluvial Valley (LMAV) has the potential to be utilized for the production of bioenergy feedstocks. Soil respiration is the gaseous emission of carbon dioxide (CO2) from microbes and plant roots in the soil, and these emissions play an important role in the global cycling of carbon. Soil respiration can act as a positive feedback affecting climate change, and has been shown to vary depending on soil moisture, temperature, and vegetation. The objectives of this study where to evaluate the effects of land use [switchgrass (Panicum virgatum ), cottonwood (Populus deltoides), and a soybean (Glycine max)-grain sorghum (Sorghum bicolor) agroecosystem] on monthly soil respiration and estimated annual CO2 emissions on a silt loam in east-central Arkansas throughout 2012 and 2013. Annual CO2 emissions were calculated by linear interpolation between monthly measurements. Soil respiration from all three ecosystems followed the same general trend: increasing from January to May and decreasing from September to December, peak fluxes differed significantly (p
Download or read book Compendium of Bioenergy Plants written by Hong Luo and published by CRC Press. This book was released on 2014-03-14 with total page 467 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the most comprehensive reviews on the latest development of switchgrass research including the agronomy of the plant, the use of endophytes and mycorrhizae for biomass production, genetics and breeding of bioenergy related traits, molecular genetics and molecular breeding, genomics, transgenics, processing, bioconversion, biosystem and chemical engineering, biomass production modeling, economics of switchgrass feedstock production etc. The book will be of interest and great value to the switchgrass research communities in both academia and industry and a handbook for agronomists, geneticists, breeders, molecular biologists, physiologists, biosystems engineers and chemical engineers.
Download or read book Exploring the Potential to Penetrate the Energy Market for Tennessee produced Switchgrass written by Shikha Chugh and published by . This book was released on 2014 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: The need for alternative sources of energy which are renewable and environmentally friendly has focused attention on the development of biomass-based energy sector. Lignocellulosic energy crops such as switchgrass are considered potential feedstock for biomass-based energy because of wide range adaptability in conjunction with lower input requirements. However, the costs of the collection, storage, and transportation of the low density feedstock from farm to conversion facilities in the switchgrass supply chain pose a major barrier to the development of bioenergy sector. The objective of the present study is to determine the optimal logistics configuration for Tennessee-produced switchgrass to penetrate the energy market via a collection/distribution hub. A mathematical programming model in integration with the Geographic Information System (GIS) was used to maximize the net present value of the profit of a collection hub/depot serving both switchgrass producers as well as bioenergy markets. A total of seven logistics scenarios were evaluated: the Baseline scenario utilized a conventional baler harvest and storage system used in the study area, while the other six scenarios incorporated various preprocessing technologies to increase the density of feedstock before delivery to local or international markets. The results showed the economic challenges of feedstock logistics: only one of the seven evaluated logistics configurations was found to be profitable for the collection hub/depot with the given assumptions. With an increase in fuel prices, it was even difficult to penetrate the energy markets for Tennessee produced switchgrass. However, if investment risk could be lower, two logistics configurations targeting international markets would become profitable. The results imply that government intervention in the bioenergy industry in the form of incentives, policies, or carbon trading mechanism can reduce the risk of investment in this market and hence increase the profitability and prompt the development of advanced bioenergy industry.
Download or read book The Potential of Producing Bioenergy Crops on Conservation Reserve Program Land in Missouri Iowa Nebraska and Kansas MINK Region to Mitigate Carbon Dioxide Emissions written by Loise N. Wambuguh and published by . This book was released on 2010 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concerns about global warming and climate change have generated increasing interest in development of bioenergy crops as a potential source of low-carbon energy. The goal of this research was to quantify environmental and economic effects of using the U.S. CRP land to produce large-scale bioenergy crops. The APEX model was used to evaluate the potential of switchgrass and hybrid poplar production to provide biomass feedstock, sequester soil carbon, and simultaneously provide other environmental co-benefits including improvement of soil and water quality in the MINK region. The environmental results indicate that the level of biomass yields and change in soil organic carbon differ with type of bioenergy crop, soil type, climatic conditions, and cultural management. Converting CRP land into bioenergy crop production and adopting conservation management practices significantly reduced sediment, nitrogen, and phosphorus loading into water bodies relative to traditional food crop production under conventional and conservation tillage practices. Results on economic effects of reverting CRP land into traditional crop production show a decline in prices of major U.S. commodities and federal government saving of nearly $ 1.7 billion annually on CRP rental payments. Putting some cropland currently under tradition crop production to produce conservation buffers has insignificant impact on commodity prices. Quantified information on environmental and economic effects of producing large-scale bioenergy crops assist policymakers develop sustainable and balance of energy-agriculture-environmental policies.
Download or read book Economics of Switchgrass in the Great Plains written by Victoria Omojeso and published by . This book was released on 2020 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fossil fuels account for approximately three quarters of anthropogenic carbon emissions (Houghton et al., 2001). Cleaner alternative sources of fuels that release less carbon dioxide (CO2) are required to reduce carbon emission affecting global climate change. In 2015 the Intergovernmental Panel on Climate Change set forth a goal to limit global temperature increases to 2°C; however, to accomplish this goal, negative emissions technologies such as bioenergy with carbon capture and storage (BECCS) must be developed. Bioenergy crop such as switchgrass, remove atmospheric CO2 as they grow and have potential to be used in a carbon capture and storage (CCS) process. Switchgrass is being evaluated as a potential feedstock source for cellulosic biofuels and many studies have assessed the biophysical potential over large areas and across different geographic locations ((Gu, Wylie, & Howard, 2015) (Hartman, Nippert, & Springer, 2012; Hartman and Nippert, 2012). However, the economic potential of producing switchgrass, accounting for profitability relative to alternative crops, has received less research attention. Switchgrass production must not only be biophysically possible, but must also be profitable for BECCS to be adopted on a large scale as a negative emission technology to successfully mitigate climate change. I added economic feasibility to biophysical potential to evaluate the economics of switchgrass in the Great Plains. The result from this study can help farmers in making economic decisions regarding converting to switchgrass production and biofuel investors make decisions about switchgrass development in the Upper Missouri River Basin (UMRB). I use the switchgrass productivity model from Gu et al. 2015 to determine switchgrass biophysical potential (yields/acre). I then use switchgrass yields by sub-regions in annual farm budget to predict the economic potential of switchgrass in these sub-regions under different price scenarios. I also predict the feasibility of farmers in the UMRB converting to producing switchgrass based on the predicted economic potential. Results suggest that only 77 million acres of land may be available for switchgrass production in the UMRB. Moreover, for switchgrass to be economically viable in the regions, weighted average annual switchgrass yield must exceed 2.447, 3.055, 2.376 and 1.024 tons per acre in CMP, EHP, NGP and WBR sub-regions of the UMRB, and in order to break-even in the short run, total revenue per acre from switchgrass production would need to be at least $118.56, $128.73, $128.92, and $130.56 per acre in WBR, NGP, CMP, and EHP respectively. Furthermore, producers will need to receive prices that are greater than $100.00/ton to be profitable in CMP, EHP, and NGP. However, a price above $100.00 will be needed to encourage farmers to convert into large scale switchgrass production in the Upper Missouri River Basin.
Download or read book Analysis of Bioenergy Crops as a Production Alternative for a Representative East Tennessee Beef and Crop Farm written by Andrew Preston Griffith and published by . This book was released on 2009 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: The United States has increased its emphasis on energy independence and has developed legislation that promotes the development of alternative energy sources. One potential energy source being studied is the perennial cellulosic feedstock switchgrass. Switchgrass is currently being produced for experimental purposes and not on a commercial scale. The first objective of this research was to evaluate, under risk, the switchgrass contract incentives that could encourage a representative farmer in Monroe County, Tennessee to produce switchgrass. The second objective was to evaluate, under risk, the contract type and terms that would induce a representative farmer to produce switchgrass. Net returns and variability of net returns (risk) for traditional enterprises and switchgrass contracting alternatives on three different soil types were analyzed using stochastic dominance methods. Corn was found dominant on the more productive Dunmore and Dewey soils and cow-calf production was found dominant on the less productive Dandridge soil for traditional enterprises. Results indicate spot market prices based on switchgrass' energy equivalency to wholesale gasoline would not encourage production. Results suggest that the UT Biofuels Initiative contract would provide enough revenue and risk protection to encourage production on poorer soils such as Dandridge soil, but additional revenue sources were favorable to encouraging more production based on risk behaviors. Contracts with spot market prices and Biomass Crop Assistance Program (BCAP) provisions required additional revenue from electricity and European carbon credits (ECX) to support production on lower quality soils. A quadratic programming model was used to determine the risk efficient mix of traditional enterprises and switchgrass contracting alternatives on the representative farm. Results suggest that the base UT contract would induce switchgrass production on the poorer Dandridge soil for risk neutral and risk averse producers. The UT contract with ECX and BCAP with electricity and ECX induced risk averse producers to grow slightly more switchgrass on the Dandridge soil than the UT contract without ECX and BCAP. Expected revenue contracts paying $75/dry ton with ECX and $35/dry ton with BCAP and ECX were beneficial in spurring production on the higher quality Dunmore and Dewey soils.
Download or read book Changes in Soil Carbon and Nitrogen Associated with Switchgrass Production written by Porfirio Jose Lobo Alonzo and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Greater knowledge of the short- and long-term effects of biomass production practices on soil biological and chemical properties is needed to determine influences on sustainable land management. Soil samples under switchgrass (Panicum virgatum L.), other forage grasses, cultivated crops, and forest were collected seasonally at six locations. Soil organic C (SOC), total N, soil microbial biomass C (SMBC) and N (SMBN), soil mineralizable C and N, and basal soil respiration (BSR) were in general greatest under long-term coastal bermudagrass [Cynodon dactylon (L.) Pers.] pasture (>40 years), second highest under Alamo switchgrass and kleingrass (Panicum coloratum L.) planted in 1992 and forest, followed by Alamo switchgrass planted in 1997, and was lowest under the cultivated soils. Soil organic C at 0-5 cm was 42-220% greater in soils under Alamo switchgrass planted in 1992 than cultivated soils, except at College Station where SOC values under Alamo planted in 1992 and the cultivated rotation were not significantly different. Although the rotation treatment is cultivated at this location, two high residue crops are used, wheat (Triticum aestivum L.) and sorghum [Sorghum bicolor (L.) Moench.]. Similar trends were noted for total N, SMBC, SMBN, mineralizable C and N, BSR, and the ratio of SMBC/SOC. Insufficient information was collected in this study to determine whether the parameters evaluated for forest and switchgrass were different. In addition to its high yield potential, adaptation to marginal sites and tolerance to water and nutrient limitations, switchgrass appeared to be a competitive crop in terms of land sustainability, resulting in enhanced soil quality characteristics compared to long-term cultivated soils.
Download or read book Mechanisms of Ecosystem Carbon Storage and Stability in Temperate Bioenergy Cropping Systems written by Adam Charles von Haden and published by . This book was released on 2017 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: Expansion of agricultural lands to meet the growing demand for bioenergy crops in the United States will affect terrestrial ecosystem carbon storage. Considering that the reduction of net carbon emissions is a primary goal of biofuels, changes in ecosystem carbon storage will influence the overall efficacy of bioenergy cropping systems (BCS). The overall objective of this research was to better understand the mechanisms of ecosystem carbon change in BCS to make better predictions under land use change scenarios. In a two-year study at Arlington, WI, USA (ARL), the net ecosystem carbon balance (NECB) was more favorable in an annual, continuous no-till maize (Zea mays L). system compared to a perennial switchgrass (Panicum virgatum L.) system. The NECB difference was most notably attributable to greater aboveground litter return rates, lower autotrophic soil respiration, and lower heterotrophic soil respiration in maize compared to switchgrass. Greater litter return in maize was a function of greater aboveground net primary production and management decisions regarding biomass harvest proportion. Annual growth and maintenance respiration of belowground biomass were higher in switchgrass than maize, which likely reflects differences in relative belowground growth rates and life histories (i.e. perennial vs. annual). Notable seasonal juxtapositions in soil temperature and moisture (soil microclimate) were evident between perennial and annual systems, with annual systems showing more extreme fluctuations, but the differences in soil microclimate did not directly explain the observed contrasts in heterotrophic soil respiration between systems. In a five-year study of maize, switchgrass, prairie, and hybrid poplar (Populus nigra × P. maximowiczii A. Henry 'NM6') bioenergy cropping systems, increases in the aggregate-occluded soil organic carbon fraction were observed only in the poplar system at ARL. At Kellogg Biological Station, MI, USA (KBS), a lower fertility site with sandier soils, decreases in the aggregate-occluded fraction were observed in all systems except for poplar. Changes in the aggregate-occluded fraction were related to litter quality and soil clay content. Overall, these results indicate that litter inputs are an important consideration for all BCS and that perennial cropping systems may not always provide carbon storage benefits over annual cropping systems.
Download or read book Mechanisms of Ecosystem Carbon Storage and Stability in Temperate Bioenergy Cropping Systems written by Adam C. Von Haden and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Expansion of agricultural lands to meet the growing demand for bioenergy crops in the United States will affect terrestrial ecosystem carbon storage. Considering that the reduction of net carbon emissions is a primary goal of biofuels, changes in ecosystem carbon storage will influence the overall efficacy of bioenergy cropping systems (BCS). The overall objective of this research was to better understand the mechanisms of ecosystem carbon change in BCS to make better predictions under land use change scenarios. In a two-year study at Arlington, WI, USA (ARL), the net ecosystem carbon balance (NECB) was more favorable in an annual, continuous no-till maize (Zea mays L). system compared to a perennial switchgrass (Panicum virgatum L.) system. The NECB difference was most notably attributable to greater aboveground litter return rates, lower autotrophic soil respiration, and lower heterotrophic soil respiration in maize compared to switchgrass. Greater litter return in maize was a function of greater aboveground net primary production and management decisions regarding biomass harvest proportion. Annual growth and maintenance respiration of belowground biomass were higher in switchgrass than maize, which likely reflects differences in relative belowground growth rates and life histories (i.e. perennial vs. annual). Notable seasonal juxtapositions in soil temperature and moisture (soil microclimate) were evident between perennial and annual systems, with annual systems showing more extreme fluctuations, but the differences in soil microclimate did not directly explain the observed contrasts in heterotrophic soil respiration between systems. In a five-year study of maize, switchgrass, prairie, and hybrid poplar (Populus nigra × P. maximowiczii A. Henry 'NM6') bioenergy cropping systems, increases in the aggregate-occluded soil organic carbon fraction were observed only in the poplar system at ARL. At Kellogg Biological Station, MI, USA (KBS), a lower fertility site with sandier soils, decreases in the aggregate-occluded fraction were observed in all systems except for poplar. Changes in the aggregate-occluded fraction were related to litter quality and soil clay content. Overall, these results indicate that litter inputs are an important consideration for all BCS and that perennial cropping systems may not always provide carbon storage benefits over annual cropping systems.
Download or read book Carbon Sequestration and Biomass Production Potentials of Switchgrass pine Agroforestry Systems in the Southeastern Coastal Plain written by Martin R. Day and published by . This book was released on 2015 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: Author's abstract: Global climate change is the biggest environmental challenge of this century. Potential climate change adaptation and mitigation strategies are to replace fossil fuels with bioenergy sources that have near-zero net CO2 emission and to utilize practices that promote carbon sequestration. This study assesses the soil carbon sequestration and bioenergy production potentials of switchgrass (Panicum virgatum) and longleaf pine (Pinus palustris) agroforestry systems in the southeastern coastal plain. Switchgrass has high biomass yield potential under low nutritional and management requirements and longleaf pine is a common native tree species in the southeastern coastal plain. The primary goal of this study was to establish a first-year rotation of switchgrass amongst three fertilizer treatments across four stands of longleaf pine to assess biomass production, carbon sequestration, and isotopic identification of soil carbon sources (C3 vs C4 plants). The three fertilizer treatments were no fertilizer, inorganic, and organic. The N:P:K ratio for both inorganic and organic fertilizers were 11:2:2. Inorganic fertilizer resulted highest yield of switchgrass under the agroforestry systems compared to the monoculture stands of switchgrass. The comparison between before and after study soil carbon stocking did not show any significant carbon sequestration in the study plots. The isotopic analysis revealed that the predominant carbon source came from C3 plant (pine) contributions, probably a result of pine timber practices that were established at the field sites for many years prior to the study. The presence of longleaf pine artificial stands may have favored the establishment of switchgrass when compared to monoculture planting. Since no carbon was sequestered within the one year timeframe, an extended study needs to be conducted for further insight on how much carbon can be sequestered over multiple seasons of implementing this practice.
