Download or read book Impacts of Changing Precipitation on Nitrogen Cycling in Different Landscape Positions and Cropping Systems written by Kathryn Glanville and published by . This book was released on 2020 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil nitrogen (N) influences crop yields and can interact with climate change. Soil N has many transformations and transfers that are hard to quantify and control. These N transformations and transfers are mediated by many factors, including temperature, water, and carbon. Thus, impending climate change may strongly affect N cycling across cropping systems. To minimize N losses and increase crop production, we must maximize N use efficiency (NUE). Past research shows precipitation and soil moisture act as the primary physical drivers of terrestrial N cycling and losses. To improve NUE with changing precipitation patterns, controls on N cycling in terrestrial systems must be identified. Thus, experiments to elucidate the linkage between hydrological and biogeochemical controls are valuable (Chapter 1). Many aspects of the N cycle are influenced by a changing climate - two are especially important: nitrous oxide fluxes (N2O) and biological nitrogen fixation (BNF). N2O is a powerful greenhouse gas with over 250 times the radiative forcing of CO2. In Chapter 2, I test the hypothesis that changing rainfall patterns strongly alter N2O fluxes in agricultural soils as modulated by cropping system. I use rainfall manipulation shelters to expose soils to the same amount of rainfall delivered at different intervals (3-days, 14-days, and 28-days). Results from the 2016 and 2017 field seasons show cumulative N2O fluxes were 1.4 to 2 times higher when rainfall occurred in 28-day rather than shorter intervals in corn systems. Fluxes were related to changes in denitrifier enzyme activity for both years. In switchgrass systems N2O emissions were not significantly affected by rainfall intervals.In Chapter 3, I test the hypothesis that changing rainfall patterns that alter N2O fluxes will be modulated by landscape position as landscape position affects soil texture and carbon. Over two field seasons cumulative N2O fluxes were higher in toeslope positions than in summit positions, and longer rainfall intervals had higher fluxes in summits only, consistent with higher soil carbon and finer soil texture in toeslope positions. Knowledge of these landscape patterns deserve inclusion in models of current and future climate change effects in order to better quantify and mitigate agricultural N2O fluxes.In Chapter 4, I test the hypothesis that BNF is particularly vulnerable to changing rainfall patterns in till vs. no-till and in summit vs. toeslope positions due to differences in texture and organic matter. Results reinforce the importance of topographic position for predicting soybean BNF and show that summit positions are more sensitive to additional rainfall. Results also show changes in rainfall intensity affect BNF in tilled differently than in no-till soils. Models that incorporate these interactions will be better able to characterize legume crop performance and N fixation across landscapes and improve global estimates for BNF. Understanding these interactions in the agricultural US Midwest may help us improve sustainability of N use in cropping systems with a changing climate.

Download or read book The European Nitrogen Assessment written by Mark A. Sutton and published by Cambridge University Press. This book was released on 2011-04-14 with total page 665 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presenting the first continental-scale assessment of reactive nitrogen in the environment, this book sets the related environmental problems in context by providing a multidisciplinary introduction to the nitrogen cycle processes. Issues of upscaling from farm plot and city to national and continental scales are addressed in detail with emphasis on opportunities for better management at local to global levels. The five key societal threats posed by reactive nitrogen are assessed, providing a framework for joined-up management of the nitrogen cycle in Europe, including the first cost-benefit analysis for different reactive nitrogen forms and future scenarios. Incorporating comprehensive maps, a handy technical synopsis and a summary for policy makers, this landmark volume is an essential reference for academic researchers across a wide range of disciplines, as well as stakeholders and policy makers. It is also a valuable tool in communicating the key environmental issues and future challenges to the wider public.

Download or read book Nitrogen Cycling in Ecosystems of Latin America and the Caribbean written by G. Philip Robertson and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: The large and rapidly expanding body ofliterature related to nitrogen cycling in both managed and native terrestrial ecosystems reflects the importance accorded to the behaviour of this vital and often limiting nutrient. Research at the organism, ecosystem and landscape levels commonly addresses questions concerning nitrogen acquisition, internal cycling and retention. Goals for this research include increased agricultural productivity and a better understanding of human impact on local, regional and global nitrogen cycles. Nitrogen cycle research in tropical regions has a long and distinguished history. Research on different aspects of nitrogen cycling in ecosystems of the tropics has been carried out in many regions. In relatively few instances has there, however, been a focus on the biogeochemical cycles at the ecosystem level. The meeting resulting in this volume was an attempt to bring together existing information on nitrogen cycling in ecosystems of Latin America and the Caribbean and discuss this in an ecosystem context.

Download or read book New Perspectives on Nitrogen Cycling in the Temperate and Tropical Americas written by SCOPE Nitrogen Project and published by Springer Science & Business Media. This book was released on 1999-07-31 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nitpov - An etymology of nitrogen and other related words. Contemporary and pre-industrial global reactive nitrogen budgets. Nitrogen stable isotopic composition of leaves and soil: Tropical versus temperate forests. The globalization of N deposition: ecosystem consequences in tropical environments. A nitrogen budget for late-successional hillslope tabonuco forest, Puerto Rico. The impact of accelerating land-use change on the N-cycle of tropical aquatic ecosystems: Current conditions and projected changes. Nitrogen yields from undisturbed watersheds in the Americas. Nitrogen cycling and anthropogenic impact in the tropical interametican seas. Ecosystem constraints to symbiotic nitrogen fixers: a simple model and its implications. Do top-down and bottom-up controls interact to exclude nitrogen-fixing cyanobacteria from the plankton of estuaries? An exploration with a simulation model. The presence of nitrogen fixing legumes in terrestrial communities: Evolutionary vs ecological considerations. Nitrogen limitation in dryland ecosystems: Responses to geographical and temporal variation in precipitation.

Download or read book Climatic Variability and Change in the Midwestern United States written by William James Baule and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: How has the background climate of the Midwestern United States changed over recent decades and how has this affected nitrate leaching? These are the core questions addressed in this dissertation, through three self-contained studies focused on different aspects of the climate-agriculture interface in the Midwestern United States. In Chapter 2, statistical methods are used to quantify the solar radiation biases present in a widely used reanalysis-based hydrometeorological dataset over space, implement statistical bias correction and interpolation to address the spatial nature of this bias, and quantify the impacts of the solar radiation bias and proposed correction on simulated maize yields and water stress. Correction of reanalysis solar radiation alone brought simulated yield and water usage more in line with simulations forced with in-situ solar radiation. Chapter 3 examines changes in precipitation, utilizing a unique approach to station screening during the period 1951-2019 over a region encompassing the Great Lakes and broader Midwestern regions, of the United States. A multiple tier procedure was utilized to identify high quality input data series from the Global Historical Climatology Network-Daily dataset. Temporal and spatial trends were analyzed for a broad range of related annual and seasonal indicators ranging from accumulated totals and frequency of threshold events to event duration and potential linkages with total precipitable water. Our analyses confirm the results of previous studies while providing unique insights to data quality and seasonality. The trends of the indicators in our study exhibited more cohesive spatial patterns and temporal similarities when compared with studies with different quality control criteria, illustrating the importance of quality control of observations in climatic studies and highlighting the complexity of the changing character of precipitation. In Chapter 4, System Approach to Land Use Sustainability, a process-based crop model was applied with gridded soil and meteorological data using a yield stability zone concept to simulate corn and soybean production in 14 Midwestern states at the sub-field scale during the 1989-2019 period. Five zones based on multi-year yield stability were simulated for each field at 30m x 30m resolution, with zones being relative to each individual field. Outputs were evaluated using a nitrogen balance approach to establish zone-specific statistical distributions of nitrate leaching across the 14 states, specifically highlighting periods with changing and highly variable precipitation. Results indicate that low stable, unstable hill tops, and unstable slope zones are associated with an outsized contribution to overall nitrate leaching and that unstable zones exhibit variable year-to-year response to weather tied to their position in the landscape. Spatial analysis of the results suggests leaching is tied to precipitation variability, water stress, and total precipitation amount. In aggregate, the chapters presented here highlight the interconnectedness of the soil-plant-atmosphere continuum to changes in hydrologic regime and sensitivity to the biases in the data used to conduct analyses, run models, and from which conclusions are drawn. The study findings shed light on the potential for improved management of agricultural fields and illustrate how process-based crop models can be useful for designing management practices to reduce environmental pollution and increase profits to producers.

Download or read book Nitrogen Cycling in the Americas Natural and Anthropogenic Influences and Controls written by Luiz A. Martinelli and published by Springer Science & Business Media. This book was released on 2007-01-19 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in our understanding of the nitrogen cycle and the impact of anthropogenic activities on regional to global scales depend on the expansion of scientific studies to these fast-developing regions. This book presents a series of studies from across the Americas whose aim is to highlight key natural processes that control nitrogen cycling as well as discuss the main anthropogenic influences on the nitrogen cycle in both the tropical and temperate regions of the Americas.

Download or read book Nitrogen Cycling in Animal Legume and Fertilizer based Cropping Systems written by Glendon Hamilton Harris and published by . This book was released on 1993 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Properties and Management of Soils in the Tropics written by Pedro A. Sanchez and published by Cambridge University Press. This book was released on 2019-01-10 with total page 685 pages. Available in PDF, EPUB and Kindle. Book excerpt: Long-awaited second edition of classic textbook, brought completely up to date, for courses on tropical soils, and reference for scientists and professionals.

Download or read book Combined Effects of Short term Rainfall Patterns and Soil Texture on Nitrogen Cycling A Modeling Analysis written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Precipitation variability and magnitude are expected to change in many parts of the world over the 21st century. We examined the potential effects of intra-annual rainfall patterns on soil nitrogen (N) transport and transformation in the unsaturated soil zone using a deterministic dynamic modeling approach. The model (TOUGHREACT-N), which has been tested and applied in several experimental and observational systems, mechanistically accounts for microbial activity, soil-moisture dynamics that respond to precipitation variability, and gaseous and aqueous tracer transport in the soil. Here, we further tested and calibrated the model against data from a precipitation variability experiment in a tropical system in Costa Rica. The model was then used to simulate responses of soil moisture, microbial dynamics, nitrogen (N) aqueous and gaseous species, N leaching, and N trace-gas emissions to changes in rainfall patterns; the effect of soil texture was also examined. The temporal variability of nitrate leaching and NO, N2, and N2O effluxes were significantly influenced by rainfall dynamics. Soil texture combined with rainfall dynamics altered soil moisture dynamics, and consequently regulated soil N responses to precipitation changes. The clay loam soil more effectively buffered water stress during relatively long intervals between precipitation events, particularly after a large rainfall event. Subsequent soil N aqueous and gaseous losses showed either increases or decreases in response to increasing precipitation variability due to complex soil moisture dynamics. For a high rainfall scenario, high precipitation variability resulted in as high as 2.4-, 2.4-, 1.2-, and 13-fold increases in NH3, NO, N2O and NO3− fluxes, respectively, in clay loam soil. In sandy loam soil, however, NO and N2O fluxes decreased by 15% and 28%, respectively, in response to high precipitation variability. Our results demonstrate that soil N cycling responses to increasing precipitation variability depends on precipitation amount and soil texture, and that accurate prediction of future N cycling and gas effluxes requires models with relatively sophisticated representation of the relevant processes.

Download or read book Carbon mediated Ecological and Physiological Controls on Nitrogen Cycling Across Agricultural Landscapes written by Andrew James Curtright and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The sustainable intensification of agriculture relies on the efficient use of ecosystem services, particularly those provided by the microbial community. Managing for these ecosystem services can improve plant yields and reduce off-site impacts. For instance, increasing plant diversity is linked to positive effects on yield, and these beneficial effects are often mediated by the microbial community and the nutrient transformations it carries out. My dissertation has aimed to elucidate the mechanisms by which plant diversity improves agricultural production. In particular, I have focused on how changes to the amount and diversity of carbon (C) inputs affects soil microorganisms involved in the nitrogen (N) cycle. My work spans multiple scales of observation: from a global meta-analysis to mechanistic studies utilizing denitrification as a model system.In a global meta-analysis, I found that increasing plant diversity through intercropping yields a net increase in extracellular enzyme activity. This effect varied by plant species and soil type suggesting that increases in the quality of nutrient inputs mediates these positive effects on microbial activity. Then, I looked at how intercropping cover crops into corn affects soil nutrient pools and microbial activities in a field experiment. No effect of interseeding cover crops into corn was found on soil nutrient pools or microbial activities. However, by analyzing differences in relationships between nutrient pools and microbial activities at two locations throughout Michigan, I was able to describe how the availability of dissolved organic C (DOC) drives differences in microbial N-cycling processes. I then investigated how C availability drives activity in microbial hotspots within the soil by comparing differences in denitrification potential in bulk soil versus the rhizospheres of corn and interseeded cover crops. Here, I found that denitrification rates were increased in the rhizospheres of all plant types, and this effect varied depending on the species of plant. I was able to further differentiate the impact of DOC and microbial biomass C on the rhizosphere effect and found that C availability was the primary driver of differences in denitrification rates between rhizospheres. Since plants provide many different forms of C to soil microbes, it is important to understand how the chemistry of C inputs affects microbial activity. I used a series of C-substrate additions to determine how C chemistry affects denitrifiers. I found that amino acids and organic acids tended to stimulate the most nitrous oxide (N2O) production and reduction. Although management and site affected overall rates of denitrification, C-utilization patterns of microbes were mostly similar between locations. To identify the mechanisms responsible for these effects, I performed a final experiment to track how denitrifiers utilized different C compounds. The C substrates that stimulated the most complete reduce of N2O also were utilized with the lowest C-use efficiency (CUE). This suggests possible trade-offs between N2O reduction and CUE, with important implications for how to manage microbial communities.Overall, my work demonstrates that land management can impact microbial community activity by influencing the identity of soil C inputs. While the importance of increasing soil C inputs has been known, this dissertation supports the notion that the chemical identity of C inputs can exert significant controls on microbial activity. Moreover, by comparing microbial traits I highlight the importance of trade-offs in how microbially mediated C- and N cycling are coupled.

Download or read book Carbon and Nitrogen Cycling in Soil written by Rahul Datta and published by Springer. This book was released on 2019-09-04 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several textbooks and edited volumes are currently available on general soil fertility but‚ to date‚ none have been dedicated to the study of “Sustainable Carbon and Nitrogen Cycling in Soil.” Yet this aspect is extremely important, considering the fact that the soil, as the ‘epidermis of the Earth’ (geodermis)‚ is a major component of the terrestrial biosphere. This book addresses virtually every aspect of C and N cycling, including: general concepts on the diversity of microorganisms and management practices for soil, the function of soil’s structure-function-ecosystem, the evolving role of C and N, cutting-edge methods used in soil microbial ecological studies, rhizosphere microflora, the role of organic matter (OM) in agricultural productivity, C and N transformation in soil, biological nitrogen fixation (BNF) and its genetics, plant-growth-promoting rhizobacteria (PGPRs), PGPRs and their role in sustainable agriculture, organic agriculture, etc. The book’s main objectives are: (1) to explain in detail the role of C and N cycling in sustaining agricultural productivity and its importance to sustainable soil management; (2) to show readers how to restore soil health with C and N; and (3) to help them understand the matching of C and N cycling rules from a climatic perspective. Given its scope, the book offers a valuable resource for educators, researchers, and policymakers, as well as undergraduate and graduate students of soil science, soil microbiology, agronomy, ecology, and the environmental sciences. Gathering cutting-edge contributions from internationally respected researchers, it offers authoritative content on a broad range of topics, which is supplemented by a wealth of data, tables, figures, and photographs. Moreover, it provides a roadmap for sustainable approaches to food and nutritional security, and to soil sustainability in agricultural systems, based on C and N cycling in soil systems.

Download or read book Linking Carbon and Nitrogen Cycling to Plant soil microbial Interactions at the Field Soil Pedon and Micro scales Within Long term Conventional Low input and Organic Cropping Systems written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite the greatly increased productive capacity of current-day cropping systems, the shortcomings associated with conventional, high-intensity cropping systems and the growing threat of global climate change, warrant the identification of crop management practices that promote long-term agricultural sustainability and productivity. Unlike conventional cropping practices, which include synthetic nitrogen and pesticide use, alternative crop management practices, e.g., cover cropping, tillage reduction, organic amendment additions, and reducing or eliminating synthetic fertilizer use, have emerged as integrated and ecologically sound approaches to enhance agroecosystem functioning and services. Yet, mechanisms governing the differences in soil quality and crop yields among alternative cropping systems and conventional systems remain unclear. The aim of this dissertation study was to understand and quantify the mechanisms governing the relationship between carbon and nitrogen cycling and the interactions between plants, soil, and microorganisms within long-term conventional (annual synthetic fertilizer), low-input (alternating synthetic fertilizer and cover crop additions), and organic (annual manure- and cover crop additions) cropping systems, at the field-, soil pedon-, and micro-scales. A multi-scaled approach, including agronomic experiments, stable isotopes (13C and 15N), soil fractionation techniques, and microbiological analyses (e.g., functional gene quantification and phospholipid fatty acid assays), was employed to study mechanisms of soil carbon and nitrogen stabilization and loss and to draw links between microbial populations and carbon and nitrogen processing across different agroecosystems. Data from this research only partly corroborated the global hypothesis: the effects of long-term, low-input crop management enhance microbial-mediated carbon and nitrogen turnover in different soil microenvironments and optimize the balance between carbon and nitrogen stabilization and loss compared to the conventional and organic cropping systems. Only a weak relationship between short-term microbial community structure and long-term carbon and nitrogen sequestration was found across the three cropping systems. The conclusion drawn is that the effects of long-term crop management are dictated by complex trade-offs between soil carbon and nitrogen stabilization, microbial abundance and activity, nitrogen losses, crop productivity, and the quantity and quality of carbon and nitrogen inputs in alternative cropping systems.

Download or read book Impact of Ecologically Based Nutrient Management Strategies on N20 Emissions from Grain Cropping Systems written by Zhen Han and published by . This book was released on 2017 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nitrous oxide (N2O) is a potent greenhouse gas and a strong ozone-depletion substance. There is an urgent need to improve management of agricultural nitrogen to reduce N2O emissions from agricultural soils. A vast body of scientific research has investigated the impact of fertilizer-based management strategies, while fewer studies have examined the ecologically-based nutrition management practices (ENM) that manage carbon and nitrogen additions simultaneously and target multiple processes of the nitrogen cycle (e.g. the use of diversified rotations and cover crops). The objective of this work was to better understand the impacts of ENM practices and its interaction with environmental variables on N2O emissions through a meta-analysis, an on-farm experiment, and a 15N tracer experiment. I performed a meta-analysis on 596 pairwise comparisons (129 papers) to compare the efficacy of a wide range of management strategies. ENM practices generally had N2O emissions that were not significantly different from conventional fertilizer-based practices, however this outcome is based on a small number of studies and N was frequently over-applied in the ENM systems. I also conducted an on-farm experiment to assess the interactive effects of landscape characteristics and management regimes. I monitored N2O emissions in two adjacent grain farms in upstate New York that have both undergone the same management for 20 years. I found comparable N2O emissions from winter bare fallow- maize phase in the fertilizer-based field and the legume cover crop (red clover)- maize phase of the cover crop-based rotation. The lowest emissions were found in the winter grain (spelt)- legume cover crop growth period of the organic rotation. The impact of landscape position on N2O emissions was only significant in the fertilizer-based field but not in the cover crop-based field. I conducted a 15N crop residue exchange experiment to measure the contribution of nitrogen from a clover cover crop to N2O emissions. The study found that the dominant source of N2O fluxes shifted from aboveground biomass to belowground sources (root-derived N and soils) around 7 weeks after incorporation. This study provided quantitative evidence that the belowground nitrogen was a significant source of N2O emissions after incorporating legume cover crops. ...

Download or read book OECD Compendium of Agri environmental Indicators written by OECD and published by OECD Publishing. This book was released on 2013-06-25 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides comprehensive data and analysis on the environmental performance of agriculture in OECD countries since 1990, covering soil, water, air and biodiversity and looking at recent policy developments in all 34 countries.

Download or read book Essentials of Landscape Ecology written by Kimberly A. With and published by Oxford University Press, USA. This book was released on 2019-07 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt: Human activity during the Anthropocene has transformed landscapes worldwide on a scale that rivals or exceeds even the largest of natural forces. Landscape ecology has emerged as a science to investigate the interactions between natural and anthropogenic landscapes and ecological processes across a wide range of scales and systems: from the effects of habitat or resource distributions on the individual movements, gene flow, and population dynamics of plants and animals; to the human alteration of landscapes affecting the structure of biological communities and the functioning of entire ecosystems; to the sustainable management of natural resources and the ecosystem goods and services upon which society depends. This novel and comprehensive text presents the principles, theory, methods, and applications of landscape ecology in an engaging and accessible format that is supplemented by numerous examples and case studies from a variety of systems, including freshwater and marine "scapes."

Download or read book Soil Hydrology in a Changing Climate written by Humberto Blanco and published by CSIRO PUBLISHING. This book was released on 2022-12 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: A changing climate is causing challenges for soil and water management in many parts of the world. Current soil management practices need to be redesigned to effectively address present and future fluctuating climates. Soil Hydrology in a Changing Climate explores how soil management practices impact soil hydrological characteristics, and how we can improve our understanding of soil and water management under changing conditions. Soil hydrology includes water infiltration and soil water storage, which are critical for agricultural plant and animal production. With our future climate predicted to include hotter, drier conditions, increases in evapotranspiration as well as fewer, more intense storms, improved soil management and soil hydrology are critical to ensuring our agriculture production can meet human demand. This comprehensive book is a valuable resource for land managers, soil conservationists, researchers and others who wish to understand how different management practices affect soil and water dynamics and how these practices can be adjusted to enhance agricultural sustainability and environmental quality.

Download or read book Geomorphometry written by Tomislav Hengl and published by Elsevier. This book was released on 2008-11-20 with total page 797 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geomorphometry is the science of quantitative land-surface analysis. It draws upon mathematical, statistical, and image-processing techniques to quantify the shape of earth's topography at various spatial scales. The focus of geomorphometry is the calculation of surface-form measures (land-surface parameters) and features (objects), which may be used to improve the mapping and modelling of landforms to assist in the evaluation of soils, vegetation, land use, natural hazards, and other information. This book provides a practical guide to preparing Digital Elevation Models (DEM) for analysis and extracting land-surface parameters and objects from DEMs through a variety of software. It further offers detailed instructions on applying parameters and objects in soil, agricultural, environmental and earth sciences. This is a manual of state-of-the-art methods to serve the various researchers who use geomorphometry. Soil scientists will use this book to further learn the methods for classifying and measuring the chemical, biological, and fertility properties of soils and gain a further understaing of the role of soil as a natural resource. Geologists will find value in the instruction this book provides for measuring the physical features of the soil such as elevation, porosity, and structure which geologists use to predict natural disasters such as earthquakes, volcanoes, and flooding. * Technical details on a variety of software packages allow researchers to solve real-life mapping issues * Provides soil and agronomy researchers best practice techniques for soil data analysis to assist in enhanced land-use and planning * Offers geologists essential tactics for better environmental management by providing a comprehensive analysis of the physical features of soil * Companion website includes access to the latest technological advancements previously unpublished in any other comprehensive source: geomorphometry software, DEM data sources, and applications