Download or read book Carbon and Nitrogen Dynamics and Microbial Community Structure of a Tall Grass Prairie Soil Subjected to Simulated Global Warming and Clipping written by Asfaw Belay Tedla and published by . This book was released on 2004 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Soil Respiration and the Environment written by Luo Yiqi and published by Elsevier. This book was released on 2010-07-20 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: The global environment is constantly changing and our planet is getting warmer at an unprecedented rate. The study of the carbon cycle, and soil respiration, is a very active area of research internationally because of its relationship to climate change. It is crucial for our understanding of ecosystem functions from plot levels to global scales. Although a great deal of literature on soil respiration has been accumulated in the past several years, the material has not yet been synthesized into one place until now. This book synthesizes the already published research findings and presents the fundamentals of this subject. Including information on global carbon cycling, climate changes, ecosystem productivity, crop production, and soil fertility, this book will be of interest to scientists, researchers, and students across many disciplines. - A key reference for the scientific community on global climate change, ecosystem studies, and soil ecology - Describes the myriad ways that soils respire and how this activity influences the environment - Covers a breadth of topics ranging from methodology to comparative analyses of different ecosystem types - The first existing "treatise" on the subject

Download or read book Role of Microbes in Climate Smart Agriculture written by Pil Joo Kim and published by Frontiers Media SA. This book was released on 2020-01-28 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Master s Theses Directories written by and published by . This book was released on 2004 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Education, arts and social sciences, natural and technical sciences in the United States and Canada".

Download or read book Responses to Long term Fertilization and Burning written by Michael A. Carson and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Anthropogenic activities impact ecosystems in numerous direct and indirect ways, affecting the cycling of carbon (C) and nitrogen (N) on local, regional and global scales. North America tallgrass prairie is an ecosystem profoundly altered by anthropogenic activities, with most native prairie converted to alternate land uses or heavily impacted by other environmental changes. While aboveground responses to anthropogenic drivers have received much attention, the responses of belowground biota, ecological processes, and nutrient allocation to land management and environmental change are poorly documented, especially over long timeframes. This research builds upon a long-term experiment (the Belowground Plot Experiment) initiated in 1986 at Konza Prairie Biological Station (Manhattan, KS). I utilized a subset of treatments to address the effects of annual burning vs. fire suppression and/or chronic N additions on soil C and N dynamics and microbial communities in tallgrass prairie. I measured a suite of soil variables related to C and N cycling during the 2012 growing season, including total soil C and N, microbial biomass C and N, in situ net N mineralization, potential N mineralization, in situ CO2 efflux, and potentially mineralizable soil C.I also assessed changes in microbial community composition using microbial phospholipid fatty acids (PLFA) profiles. Annual burning significantly (p[less then or equal to]0.05) increased the soil C:N ratio and in situ CO2 efflux, while decreasing potential ammonification and nitrification rates. Annual burning also increased total PLFA mass and relative abundance of fungi. Chronic N addition (100 kg N ha−1 year−1) significantly reduced the soil C:N ratio, while increasing total soil N and potential nitrification and ammonification rates. Chronic N addition reduced potential C mineralization, microbial biomass C and N, and altered microbial community composition by increasing abundance of bacterial PLFAs and reducing fungal PLFAs. Sampling date also significantly affected many variables. These results indicate that different fire regimes and chronic N enrichment over decades affects soil C and N pools and transformations, as well as microbial biomass and composition. In total, this study highlights the importance of long-term ecological research and identifies likely changes in tallgrass prairie nutrient dynamics and soil microbial communities under increased N and frequent burning.

Download or read book Grassland Carbon and Nitrogen Dynamics written by Wylie Harris and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Plant production and soil microbial biomass (SMB) in grassland ecosystems are linked by flows of carbon (C) and nitrogen (N) between the two groups of organisms. In native mixed grasslands of the southern Great Plains, these cycles are strongly influenced by climate. They may also be modulated by the timing and intensity of disturbances such as fire and clipping. We assessed the relative influence of climate and disturbance on plant community and soil C and N dynamics. Combined effects of fire and clipping were assessed in a 2x3 factorial design including spring fire and light clipping or continuous clipping. Seasonal fire effects were evaluated in a one-way analysis incorporating spring and fall fire in unclipped plots. Plant cover and biomass (by functional type), litter mass, SMB C and N, soil density fraction concentration and composition, soil organic C, total N, and inorganic N, soil temperature and moisture, soil respiration, and net N mineralization were measured at monthly intervals. C4 grasses were unaffected by fire or clipping, probably as a result of summer drought in both study years. Clipping reduced cover of C3 annual grasses but increased that of C3 perennials, resulting in no net change in C3 grass biomass. Fire did not affect C3 grass cover or biomass. Both fire and clipping reduced litter mass. This was reflected in seasonal declines in SMB C in fire treatments, suggesting that the primary input of microbial C in this ecosystem occurs by decomposition of current-season plant litter. Litter removal offers a single mechanism by which fire-induced increases in soil temperature and reductions in light soil density fraction concentration, soil moisture, and net N mineralization rates may be explained. Lack of treatment effects on soil respiration rates suggest that plant roots represent an important component of the plant-soil C cycle, not quantified in this research. Overall, treatment effects were relatively minor compared to seasonal climate-related changes in response variables, particularly in light of repeated summer drought.

Download or read book Carbon and Nitrogen Dynamics and Microbial Ecology in Tallgrass Prairie written by Fernando Oscar Garcia and published by . This book was released on 1992 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Experimental Warming and Clipping on Metabolic Change of Microbial Community in a US Great Plains Tallgrass Prairie written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: While more and more studies are being conducted on the effects of global warming, little is known regarding the response of metabolic change of whole soil microbial communities to this phenomenon. In this study, functional gene changes at the mRNA level were analyzed by our new developed GeoChip 3.0. Soil samples were taken from a long-term climate warming experiment site, which has been conducted for ~;;8 years at the Kessler Farm Field Laboratory, a 137.6-ha farm located in the Central Redbed Plains, in McClain County, Oklahoma. The experiment uses a paired factorial design with warming as the primary factor nested with clipping as a secondary factor. An infrared heater was used to simulate global warming, and clipping was used to mimic mowing hay. Twelve 2m x 2m plots were divided into six pairs of warmed and control plots. The heater generates a constant output of ~;;100 Watts m-2 to approximately 2 oC increase in soil temperature above the ambient plots, which is at the low range of the projected climate warming by IPCC. Soil whole microbial communities? mRNA was extracted, amplified, labeled and hybridized with our GeoChip 3.0, a functional gene array covering genes involved in N, C, P, and S cycling, metal resistance and contaminant degradation, to examine expressed genes. The results showed that a greater number and higher diversity of genes were expressed under warmed plots compared to control. Detrended correspondence analysis (DCA) of all detected genes showed that the soil microbial communities were clearly altered by warming, with or without clipping. The dissimilarity of the communities based on functional genes was tested and results showed that warming and control communities were significantly different (P

Download or read book Effects of Warming and Clipping on Carbon and Nitrogen Content and Their Isotope Ratios in Soil Organic Matter Aggregates in a Tall Grass Prairie Ecosystem written by Afzal Azizullah Subedar and published by . This book was released on 2005 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Climate Legacies and Restoration History as Drivers of Tallgrass Prairie Carbon and Nitrogen Cycling written by Caitlin M. Broderick and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Climate change is expected to alter precipitation amounts and distributions, resulting in longer, more frequent periods of wet and dry conditions in the North American Central Plains. Grasslands in this region are often limited by water availability, so novel rainfall patterns will likely affect ecosystem functioning. The rates of two key carbon (C) fluxes, aboveground net primary productivity (ANPP) and soil respiration, are tightly linked to water availability in these grasslands. Moreover, the cycling of nitrogen (N), a co-limiting nutrient, is tied to soil moisture through microbially-mediated processes such as N mineralization, microbial immobilization, and nitrification. Decomposition unites these two cycles-controlling the rate of C sequestration and N release-and can be slowed by both droughted and saturated soils. There is a growing understanding that sufficiently long and/or intense precipitation anomalies (e.g., extended wet or dry periods) can affect ecosystem processes even after the climate event ceases, resulting in climate "legacy effects". Tallgrass prairies, at the eastern and wetter end of the Central Plains grasslands, are both sensitive and highly resilient to short-term climate variability but the extent to which this climate sensitivity and resilience is shaped by previous climate history is largely unknown. If altered climate patterns cause changes in key ecosystem properties such as plant communities, microbial community functioning, or soil attributes, these climate changes may exert legacies on rates of prairie C and N cycling. Finally, while the relationship between climate and intact grassland ecosystem functioning has been relatively well-studied, less than five percent of North American tallgrass prairie remains intact. As a result, the persistence of tallgrass prairies and their associated ecosystem services relies heavily on the successful restoration of functioning prairies; yet future restorations will likely occur under a more hostile climate. It is therefore important to assess how climate sensitivity and resilience develops as restored prairies mature. In this dissertation, I assessed how past and current climate conditions interact to affect C fluxes, N transformations, and decomposition rates in native tallgrass prairie. I used a long-term experiment at Konza Prairie, KS, in which rainfall was supplemented by irrigation water to release tallgrass prairies from water stress for ~25 years. In 2017, I switched the irrigation and ambient treatments in a subset of plots and added new drought treatments across both historic treatments, allowing me to assess (i) how short- and long-term climate patterns differ in their effects on prairie ecosystems, (ii) whether previous climate patterns continue to shape current prairie functioning via climate legacies, and (iii) whether previous climate altered the sensitivity of prairie C and N cycling to drought conditions. In a separate project, I imposed an experimental drought across restored prairies ranging from 4 to 22 years old and measured how the sensitivity of prairie structure and function to water stress varied with restoration age. I found that a historically wetter climate increased ANPP and soil respiration on a magnitude comparable to current wet conditions, and that a history of irrigation conferred greater drought resistance to key ecosystem processes lasting up to three years. A history of irrigation also increased net N mineralization rates and nitrification rates, and microbial C/N ratios and extracellular enzyme investment suggested reduced N limitation of belowground N cycling. This legacy of increased N supply with a history of irrigation may support the higher-than-expected rates of C fluxes after ceasing irrigation. In contrast, root decomposition rates were slowest with long-term irrigation, suggesting that the increased rates of C and N mineralization may be more due to legacy effects on SOM processing than litter decay. Notably, legacy effects across response variables were most often found in lowland prairie, suggesting that topoedaphic factors are important for determining the strength of biogeochemical climate legacies. Finally, I found that restored prairie plant communities, ANPP, soil respiration, and labile N pools were surprisingly resistant to drought across all restoration ages, offering hope that restoration efforts may not be significantly hindered by future climate variability.

Download or read book Soil Microbial Dynamics and Associative Nitrogen Fixation in Kansan Tallgrass Prairies written by Steven William Culman and published by . This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil ecosystem properties and processes which simultaneously maintain native fertility and sustain plant yields are of principal interest in sustainable agriculture. Native prairies in Kansas are relevant in this context, as they have been annually hayed with no fertilization or detectable decline in yield or soil fertility. In contrast, intensive wheat production has resulted in significant reductions in soil fertility and now requires intensive inputs to maintain yield. This study aimed to shed light on the soil microbiological differences between these two contrasting agricultural systems in an attempt to gain insight into possible mechanisms driving nutrient and energy efficiencies in these hayed prairie ecosystems. The objectives of this study were: i) to identify major differences in soil bacterial and nitrogen fixing communities between prairies and adjacent annual wheat fields, ii) to determine if dramatic losses of soil organic carbon (SOC) are a result of obsolete farming practices, or from plant community composition, and iii) to document the relative contribution of associative N-fixation to total plant N in three C4 prairie grasses. Soil analyses, microbial biomass, and terminal restriction fragment length polymorphism analyses (T-RFLP) revealed that bacterial and nitrogen fixing communities that were correlated with soil chemical, physical, and biological properties indicative of higher soil quality in prairie sites. In addition, SOC loss was documented in annual agriculture fields, even in the absence of tillage, demonstrating the large role that prairie plant communities play in maintaining soil fertility. Finally, evidence of associative N fixation was found in prairie grasses which may help alleviate N limitations and sustain long-term exports of N. Two additional studies were conducted to advance T-RFLP methodology. The first study was an evaluation of statistical multivariate analyses for T-RFLP data and yielded insight into which analyses were most appropriate given research objectives and dataset complexity. The second study yielded T-REX, a free, online software for rapid and less-biased analyses of T-RFLP data. Collectively, the results of this work suggest a greater synchrony of plant nutrient demand in prairies, which may help to explain the greater nutrient use efficiencies seen in these systems relative to wheat.

Download or read book Dynamics of Microbial Community Structure and Function in a Tallgrass Prairie Ecosystem written by Allison Michelle Veach and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to agricultural practices and urbanization, tallgrass prairie ecosystems have become threatened as

Download or read book Soil Microbial Dynamics and Associative Nitrogen Fixation in Kansas Tallgrass Prairies written by Steven William Culman and published by . This book was released on 2008 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil ecosystem properties and processes which simultaneously maintain native fertility and sustain plant yields are of principal interest in sustainable agriculture. Native prairies in Kansas are relevant in this context, as they have been annually hayed with no fertilization or detectable decline in yield or soil fertility. In contrast, intensive wheat production has resulted in significant reductions in soil fertility and now requires intensive inputs to maintain yield. This study aimed to shed light on the soil microbiological differences between these two contrasting agricultural systems in an attempt to gain insight into possible mechanisms driving nutrient and energy efficiencies in these hayed prairie ecosystems. The objectives of this study were: (i) to identify major differences in soil bacterial and nitrogen fixing communities between prairies and adjacent annual wheat fields, (ii) to determine if dramatic losses of soil organic carbon (SOC) are a result of obsolete farming practices, or from plant community composition, and (iii) to document the relative contribution of associative N-fixation to total plant N in three C4 prairie grasses. Soil analyses, microbial biomass, and terminal restriction fragment length polymorphism analyses (T-RFLP) revealed that bacterial and nitrogen fixing communities that were correlated with soil chemical, physical, and biological properties indicative of higher soil quality in prairie sites. In addition, SOC loss was documented in annual agriculture fields, even in the absence of tillage, demonstrating the large role that prairie plant communities play in maintaining soil fertility. Finally, evidence of associative N fixation was found in prairie grasses which may help alleviate N limitations and sustain long-term exports of N. Two additional studies were conducted to advance T-RFLP methodology. The first study was an evaluation of statistical multivariate analyses for T-RFLP data and yielded insight into which analyses were most appropriate given research objectives and dataset complexity. The second study yielded T-REX, a free, online software for rapid and less-biased analyses of T-RFLP data. Collectively, the results of this work suggest a greater synchrony of plant nutrient demand in prairies, which may help to explain the greater nutrient use efficiencies seen in these systems relative to wheat.

Download or read book Effects of Plant soil Interactions on Grassland Carbon Dynamics in a Changing World written by Robert Kenneth Connell and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Plants are a major conduit through which carbon moves between the atmosphere and the terrestrial biosphere. The organic inputs from plants provide energy to soil microbes which fuels microbial extracellular enzyme production. Soil microbial activity determines the proportion of plant organic inputs that remains stored in soil as organic matter or is mineralized and released back into the atmosphere as carbon dioxide. Plant-soil interactions are, therefore, a critical driver of terrestrial carbon cycling. We live in an era of human-driven change which affects every aspect of ecosystem functioning, so it is critical to understand how different global change factors modulate the plant-soil interactions that influence carbon cycling. In this dissertation I focus on the effects of four specific global change factors on plant-soil interactions in a tallgrass prairie ecosystem: (1) land-use change (i.e., fire suppression and bison removal), (2) woody encroachment, (3) plant invasion, and (4) nutrient enrichment. The overall conclusion from my dissertation research is that all four of these global change factors alter plant-soil interactions in ways that change the storage or turnover of soil carbon. First, long-term fire suppression and/or bison exclusion increases soil C content over time. This change in soil C content is associated with an increase in woody plants in the case of fire suppression or an increase in the dominance of warm-season grasses in the case of bison exclusion under a frequent fire regime. Second, potential C mineralization rates under clonal woody shrubs is higher when the microbial community is decomposing proportionally more shrub-derived organic matter, suggesting that the rate of soil C flux may be dependent on how long the soil has been occupied by woody species. Third, the invasive grass Bromus inermis induces legacy effects on soil microbial community composition and soil organic matter (SOM) decomposition rates. These legacy effects persist for at least six months post-invasive grass removal. Finally, phosphorus fertilization stimulates the rate of SOM decomposition in soil undergoing woody encroachment, but nitrogen fertilization does not. Collectively, these results suggest that the effects of many global change factors on carbon cycling is dependent on spatiotemporal context and historical factors. Additionally, since each of the global change factors I studied affected carbon cycling independently, it will be important to study the combined effects of multiple global change factors acting simultaneously in order to better predict how carbon cycles through terrestrial ecosystems as the world continues to change.

Download or read book Unveiling Microbial Carbon Cycling Processes in Key U S Soils Using Omics written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Soils process and store large amounts of C; however, considerable uncertainty still exists about the details of that influence microbial partitioning of C into soil C pools, and what are the main influential forces that control the fraction of the C input that is stabilized. The soil microbial community is genotypically and phenotypically diverse. Despite our ability to predict the kinds of regional environmental changes that will accompany global climate change, it is not clear how the microbial community will respond to climate-induced modification of precipitation and inter-precipitation intervals, and if this response will affect the fate of C deposited into soil by the local plant community. Part of this uncertainty lies with our ignorance of how the microbial community adapts genotypically and physiologically to changes in soil moisture brought about by shifts in precipitation. Our overarching goal is to harness the power of multiple meta-omics tools to gain greater understanding of the functioning of whole-soil microbial communities and their role in C cycling. We will do this by meeting the following three objectives: 1. Further develop and optimize a combination of meta-omics approaches to study how environmental factors affect microbially-mediated C cycling processes. 2. Determine the impacts of long-term changes in precipitation timing on microbial C cycling using an existing long-term field manipulation of a tallgrass prairie soil. 3. Conduct laboratory experiments that vary moisture and C inputs to confirm field observations of the linkages between microbial communities and C cycling processes. We took advantage of our state-of-the-art expertise in community "omics" to better understand the functioning soil C cycling within the Great Prairie ecosystem, including our ongoing Konza Prairie soil metagenome flagship project at JGI and the unique rainfall manipulation plots (RaMPs) established at this site more than a decade ago. We employed a systems biology approach, considering the complex soil microbial community as a functioning system and using state-of-the-art metatranscriptomic, metaproteomic, and metabolomic approaches. These omics tools were refined, applied to field experiments, and confirmed with controlled laboratory studies. Our experiments were designed to specifically identify microbial community members and processes that are instrumental players in processing of C in the prairie soils and how these processes are impacted by wetting and drying events. This project addresses a key ecosystem in the United States that current climate models predict will be subjected to dramatic changes in rainfall patterns as a result of global warming. Currently Mollisols, such as those of the tallgrass prairie, are thought to sequester more C than is released into the atmosphere, but it is not known what changes in rainfall patterns will have on future C fluxes. Through an analysis of the molecular response of the soil microbial community to shifts in precipitation cycles that are accompanied by phenologically driven changes in quality of plant C rhizodeposits, we gained deeper insight into how the metabolism of microbes has adapted to different precipitation regimes and the impact of this adaption on the fate of C deposited into soil. In doing so, we addressed key questions about the microbial cycling of C in soils that have been identified by the DOE.

Download or read book Response of Regional Sources of Tallgrass Prairie Species to Variation in Climate and Soil Microbial Communities written by Rachel Kathleen Goad and published by . This book was released on 2012 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: Restoration of resilient plant communities in response to environmental degradation is a critical task, and a changing climate necessitates the introduction of plant communities adapted to anticipated future conditions. Ecotypes of dominant species can affect associated organisms as well as ecosystem function. The extent of ecotypic variation in dominant tallgrass prairie species and the consequences of this variation for ecosystem functioning were studied by manipulating two potential drivers of plant community dynamics: climate and the soil microbial community. Longer term studies will clarify whether ecotypes of dominant prairie grasses affect ecosystem function or community trajectories differently during restoration. Ecotypes of dominant species may support different soil microflora, potentially resulting in plant-soil feedback. A second experiment tested for local adaptation of prairie plant assemblages to their soil microbial community.

Download or read book Soil Organic Carbon Dynamics and Tallgrass Prairie Land Management written by Joshua W. Beniston and published by . This book was released on 2009 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: This study was composed of two research components that examined the effects of tallgrass prairie land use changes on soil organic C (SOC). The central objective of the first study was to examine changes in SOC and a suite of soil quality parameters in former agricultural soils now under restored tallgrass prairie. This research was conducted at the Prairie Nature Center, on the OSU Marion campus in northwest Ohio. Soils from 31 year, 13 year, and 8 year- old prairies, and adjacent agricultural and lawn soils were analyzed. These soils demonstrated significant increases in SOC concentration, particulate organic matter (POM), water stable aggregation (%WSA), aggregate mean weight diameter (MWD), total porosity (ft), and available water capacity (AWC), and significant decreases in soil bulk density ([rho]b) associated with time under tallgrass prairie. The second research component observed long and short-term effects of the conversion of remnant tallgrass prairies to wheat production, in north central Kansas. Total C, microbial biomass C (MBC), and a particle size fractionation of SOC were used as indices of change. Long-term sites showed changes in all fractions analyzed, while only MBC showed significant change in the short-term study. This study provides further evidence that perennial plant communities store and cycle C, and maintain ecosystem processes at far greater levels than annual plant communities.