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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

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.

Book Carbon and Nitrogen Cycling in Soil

Download or read book Carbon and Nitrogen Cycling in Soil written by Rahul Datta and published by Springer Nature. This book was released on 2019-08-24 with total page 498 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.

Book Carbon mediated Ecological and Physiological Controls on Nitrogen Cycling Across Agricultural Landscapes

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.

Book Plant soil microbial Nitrogen Cycling Across Contrasting Organic Farms in an Intensively managed Agricultural Landscape

Download or read book Plant soil microbial Nitrogen Cycling Across Contrasting Organic Farms in an Intensively managed Agricultural Landscape written by Timothy Michael Bowles and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: How farming systems supply sufficient nitrogen (N) for high yields but with reduced N losses is a central challenge for reducing the tradeoffs often associated with N cycling in agriculture. This dissertation consists of three studies that assess how variability in organic farms across an agricultural landscape may yield insights for improving N cycling and for evaluating novel indicators of N availability. Pulses of N are common in agricultural systems and often result in N losses if N is not quickly captured by plants or soil microbes. But understanding of how root behavioral responses and microbial N dynamics interact following soil N pulses remains limited, especially in soil under field conditions relevant to actual agroecosystem processes. The first study examined rhizosphere responses to a soil N pulse in an organic farm soil. A novel combination of molecular and 15N isotopic techniques was used to investigate the response of tomato (Solanum lycopersicum L.) roots and soil N cycling to a pulse of inorganic N in an undisturbed soil patch on an organic farm. Tomato roots rapidly responded to and exploited the N pulse via upregulation of key N metabolism genes that comprise the core physiological response of roots to patchy soil N availability. The transient root gene expression response underscored the sensitivity of root N uptake to local N availability. Strong root activity limited accumulation of soil nitrate (NO3−) despite high rates of gross nitrification and allowed roots to out-compete soil microbes for uptake of the inorganic N pulse, even on the short time scale of a few days. Root expression of genes such as cytosolic glutamine synthetase, a key gene in root N assimilation, could serve as a "plant's eye view" of N availability when plant-soil N cycling is rapid, complementing more typical measures of N availability like soil inorganic N pools and bioassays of N mineralization potential. Much of the research geared toward improving N cycling takes place at research stations with fixed management factors and limited variation in soil characteristics. Better understanding of how the plant-soil-microbe interactions that underpin N availability, potential for N loss, and yields vary across working farms would help reveal how to simultaneously achieve high provisioning (yields) and regulating (low potential for N loss) ecosystem services in heterogeneous landscapes. A landscape approach was thus used in the second and third studies to assess crop yields, plant-soil N cycling, root gene expression, and soil microbial community activity and composition over the course of a tomato growing season on working organic farms in Yolo County, California, USA. The 13 selected fields were representative of organic tomato production in the local landscape and spanned a three-fold range of soil carbon (C) and N but had similar soil types, texture, and pH. Yields ranged from 22.9 to 120.1 Mg ha−1 with a mean similar to the county average (86.1 Mg ha−1), which included mostly conventionally-grown tomatoes. Substantial variability in soil inorganic N concentrations, tomato N, and root gene expression indicated a range of possible tradeoffs between yields and potential for N losses across the fields. Soil enzyme activities reflected distinct metabolic capacity in each field, such that soil C-cycling enzyme potential activities increased with inorganic N availability while those of soil N-cycling enzymes increased with soil C availability. Compared to potential enzyme activity, there was less variation in soil microbial community composition, likely reflecting the history of high soil disturbance and low ecological complexity in this landscape. The variation in potential activity of soil enzymes across the organic fields thus may be due to high plasticity of the resident microbial community to environmental conditions. Those fields in the landscape that showed evidence of tightly-coupled plant-soil N cycling, a desirable scenario in which high crop yields are supported by adequate N availability but low potential for N loss, had the highest total and labile soil C and N and received diverse types of organic matter inputs with a range of N availability. In these fields, elevated expression of cytosolic glutamine synthetase in roots (as evaluated in the first study), confirmed that plant N assimilation was high even when soil inorganic N pools were low. The on-farm approach provided a wide range of farming practices and soil characteristics to reveal how microbially-derived ecosystem functions can be effectively manipulated to enhance nutrient cycling capacity. Novel combinations of N cycling indicators (i.e. inorganic N along with soil microbial activity and root gene expression for N assimilation) would support adaptive management for improved N cycling on organic as well as conventional farms, and could overcome the uncertainty of managing N inputs accurately, especially when plant-soil N cycling is rapid.

Book Modeling Carbon and Nitrogen Dynamics for Soil Management

Download or read book Modeling Carbon and Nitrogen Dynamics for Soil Management written by M J Shaffer and published by CRC Press. This book was released on 2019-08-30 with total page 672 pages. Available in PDF, EPUB and Kindle. Book excerpt: Good management practices for carbon and nitrogen are vital to crop productivity and soil sustainability, as well as to the reduction of global greenhouse gases and environmental pollution. Since the 1950's, mathematical models have advanced our understanding of carbon and nitrogen cycling at both the micro- and macro-scales. However, many of the models are scattered in the literature, undergo constant modification, and similar models can have different names. Modeling Carbon and Nitrogen Dynamics for Soil Management clarifies the confusion by presenting a systematic summary of the various models available. It provides information about strengths and weaknesses, level of complexity, easiness of use, and application range of each model. In nineteen chapters, internationally known model developers and users update you on the current status and future direction of carbon and nitrogen modeling. The book's coverage ranges from theoretical comparison of models to application of models to soil management problems, from laboratory applications to field and watershed scale applications, from short-term simulation to long-term prediction, and from DOS-based computer programs to Object-Oriented and Graphical Interface designs. With this broad scope, Modeling Carbon and Nitrogen Dynamics for Soil Management provides the tools to manage complex carbon/nitrogen processes effectively.

Book Soil Carbon Stabilization to Mitigate Climate Change

Download or read book Soil Carbon Stabilization to Mitigate Climate Change written by Rahul Datta and published by Springer Nature. This book was released on 2021-08-25 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon stabilization involves to capturing carbon from the atmosphere and fix it in the forms soil organic carbon stock for a long period of time, it will be present to escape as a greenhouse gas in the form of carbon dioxide. Soil carbon storage is an important ecosystem service, resulting from interactions of several ecological processes. This process is primarily mediated by plants through photosynthesis, with carbon stored in the form of soil organic carbon. Soil carbon levels have reduced over decades of conversion of pristine ecosystems into agriculture landscape, which now offers the opportunity to store carbon from air into the soil. Carbon stabilization into the agricultural soils is a novel approach of research and offers promising reduction in the atmospheric carbon dioxide levels. This book brings together all aspects of soil carbon sequestration and stabilization, with a special focus on diversity of microorganisms and management practices of soil in agricultural systems. It discusses the role of ecosystem functioning, recent and future prospects, soil microbial ecological studies, rhizosphere microflora, and organic matter in soil carbon stabilization. It also explores carbon transformation in soil, biological management and its genetics, microbial transformation of soil carbon, plant growth promoting rhizobacteria (PGPRs), and their role in sustainable agriculture. The book offers a spectrum of ideas of new technological inventions and fundamentals of soil sustainability. It will be suitable for teachers, researchers, and policymakers, undergraduate and graduate students of soil science, soil microbiology, agronomy, ecology, and environmental sciences

Book Carbon and Nitrogen Flows in the Root Zone of Some Agricultural Crop Species

Download or read book Carbon and Nitrogen Flows in the Root Zone of Some Agricultural Crop Species written by Erick Zagal and published by . This book was released on 1993 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Soil Carbon Dynamics

Download or read book Soil Carbon Dynamics written by Werner L. Kutsch and published by Cambridge University Press. This book was released on 2010-01-07 with total page 301 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon stored in soils represents the largest terrestrial carbon pool and factors affecting this will be vital in the understanding of future atmospheric CO2 concentrations. This book provides an integrated view on measuring and modeling soil carbon dynamics. Based on a broad range of in-depth contributions by leading scientists it gives an overview of current research concepts, developments and outlooks and introduces cutting-edge methodologies, ranging from questions of appropriate measurement design to the potential application of stable isotopes and molecular tools. It includes a standardised soil CO2 efflux protocol, aimed at data consistency and inter-site comparability and thus underpins a regional and global understanding of soil carbon dynamics. This book provides an important reference work for students and scientists interested in many aspects of soil ecology and biogeochemical cycles, policy makers, carbon traders and others concerned with the global carbon cycle.

Book Biotic and Abiotic Drivers of Microbial Carbon and Nitrogen Cycling in Soils at the Continental Scale

Download or read book Biotic and Abiotic Drivers of Microbial Carbon and Nitrogen Cycling in Soils at the Continental Scale written by Benjamin Parker Colman and published by . This book was released on 2009 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: The pools of C and N in soil organic matter (SOM) contain 80% of the C and 90% of the N in the terrestrial biosphere, and microorganisms in the soil catalyze the turnover and release of nutrients tied up in SOM. As microbes decompose SOM they respire, producing CO2, while waste nitrogen is released as NH4+. Microbes limited by N will immobilize both NH4+ and NO3-, but recent research indicates that the soil itself can chemically incorporate both NH4+ and NO3 -. Given that NO3- is typically thought of as being unreactive, this pathway is particularly intriguing and could be a mechanism by which soils might retain a highly mobile form of N, and maintain N limitation to microbes and plants.

Book Managing Microbially mediated Nitrogen Cycling to Decrease Risk of Loss from Semi arid Rainfed Agricultural Soils

Download or read book Managing Microbially mediated Nitrogen Cycling to Decrease Risk of Loss from Semi arid Rainfed Agricultural Soils written by Louise Marjorie Fisk and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: [Truncated] More efficient management of nitrogen (N) in agricultural soils is vital to maximise food supply and minimise losses of N to the environment. Nitrification is a key pathway of detrimental N loss, as nitrate and gaseous nitrous oxide are produced. In semi-arid soils, N cycling and nitrification is not well understood during summer fallow, an important period for N loss, as most research has instead focussed on N fertiliser management during the growing season. In order to better understand and manage N cycling in cropped semi-arid soils, this thesis investigated factors contributing to risk of N loss, as well as possible solutions to decrease the risk of loss. The close link between soil N and carbon (C) cycling suggested that solutions might be found through management of soil organic matter. Soil was used from a long-term field site in the northern grainbelt of Western Australia with a range of crop residue and tillage treatments (no tillage; no tillage with burnt stubble; tillage; tillage plus additional crop residue inputs; and tillage plus crop residues run-down) that altered soil organic matter content since 2003, allowing examination of N transformation pathways without confounding effects of differing soil types or climate. Firstly, steady-state N transformations and risk of N loss (defined as gross nitrification: immobilisation ratio) were examined, in response to a range of soil temperatures, root exudate C and field treatment (tilled soil and tilled soil plus crop residues), using 15N isotopic pool dilution and turnover of 14C-labelled substrates. Tilled soil plus crop residues had 76% more total C than tilled soil. Root exudates were effective at decreasing risk of N loss by stimulating microbial N immobilisation over nitrification. In comparison, management of N loss through additional crop residue inputs was unlikely to be effective, as increased soil organic matter enhanced the supply of both C and N substrates and N cycling overall. At temperatures above 30°C, net N mineralisation was associated with decreased microbial C use efficiency, likely contributing to increases in inorganic N pools during summer fallow.

Book The Role of Labile Carbon and Its Interaction with Humus Form in Controlling Forest Soil Nitrogen Cycling

Download or read book The Role of Labile Carbon and Its Interaction with Humus Form in Controlling Forest Soil Nitrogen Cycling written by Robert Lionel Bradley and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The flux of soil C is linked to soil nutrient cycling and plant uptake but the exact nature of these relationships is unclear. Interactions between labile-C and humus form in controlling microbial and nutrient dynamics were studied. A new kinetic parameter was derived to reliably assess the potential energy supply to soil microbes. A bioassay study demonstrated that the rhizosphere of paper birch (Betula papyrifera Marsh.) seedlings increased soil available-C and microbial biomass but decreased microbial nutrient limitation; results suggest an alternative conceptual model for N cycling termed "co-metabolic N mineralization". Go-metabolic N mineralization occurred in a mull but not in a mor humus, probably as the result of changes in microbial community structure following the introduction of roots into microsites dominated by ligninolytic organisms. [...]" --

Book Carbon and Nitrogen Cycling in a Tree grass Inter cropping System in the Humid Tropics of Mexico

Download or read book Carbon and Nitrogen Cycling in a Tree grass Inter cropping System in the Humid Tropics of Mexico written by Salvador Hernández Daumás and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This work aimed to contribute to the understanding of tree - grass inter-cropping interactions so that the productivity and sustainability of extensive livestock husbandry can be increased. The work was carried out in the context of a small farm in Oaxaca, Mexico, where increases in productivity are limited by shortage of capital and where the tree component would be used as green manure. It is difficult to investigate the effectiveness of such a system by only using conventional field trials. I constructed a mathematical model to simulate how the main components of the system function under conditions that would not be evaluated in the field. Issues such as how many trees to plant and what tree species combine with grass cattle and environment, can be answered with the model. The particular features of the model are: 1) It describes an agro-ecosystem where trees perform several biological functions like nitrogen capture for use in the silvopastoral system, 2) It links grass and trees with the animal and 3) Nutrient availability depends mainly on soil organic matter decomposition and mineralisation rather than on external inputs. The present research consisted of 1) constructing the model prototype using data from the literature, 2) conducting field experiments to investigate the actual performance of the silvopastoral system, 3) perform laboratory research and greenhouse experiments complementarily to the field experiments and 4) elaborate on the carbon and nitrogen balance of the silvopastoral experiment, by combining research results and the mathematical model. The field experiment consisted of an array of 13 plots with one of the tree species Gliricidia sepium, Leucaena leucocephala, Delonix regia and Lysiloma auritum in a gradient of plant densities within a Brachiaria decumbens paddock. Results showed that the presence of trees in pastures is potentially useful for retaining nitrogen and carbon that would be lost in the grass mono-crop. Trees did not incorporate nitrogen through biological fixation, perhaps because the lack of adequate nodulation and they did not established their rooting systems to a depth beyond the grass roots (> 1.20m) so as to recover leached nutrients. However, trees produced mulch that was rich in nitrogen (3.8%) and whose decomposition rate ensures a slow release to prevent leaching. At the plant density used, the tree population caused no harm to grass as to production and nutritive value. Further increments in tree density in order to improve the potential for nitrogen capture should be evaluated in terms of the reduction of grass production. Several biological attributes of the species were determined, in some cases for the first time: biomass productivity, specific leaf area, nutritive value, phenolic content, root biomass, grass root longevity, root vertical distribution, etc. Such characterisation is useful for the understanding of the system inter-cropping and specially for the parameterisation of the silvopastoral model. Even though the mixtures proved able to survive for the span of the experiment, the sustainability of tree - grass inter-cropping as to the stabilisation of soil fertility requires longer monitoring. Other limiting factors such as phosphorus availability and the management of grazing systems have to be incorporated for an adequate evaluation of the silvopastoral system.

Book Impact of Soil Microbial Biomass and Fertiliser Source on Nitrogen Use Efficiency

Download or read book Impact of Soil Microbial Biomass and Fertiliser Source on Nitrogen Use Efficiency written by C. Bosshard and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Global population is increasing exponentially and is forecasted to be about 9 billion in 2050. During the next years fertiliser consumption also will increase as food security has to be attained. Currently, fertiliser nitrogen (N) use efficiency is on average only 50% for mineral fertiliser and even lower for animal manure. Fertiliser N which is not recovered by crops or immobilised in the soil is lost from the soil-plant system and adversely affects the environment. Hence, one of the biggest challenges in agriculture is to increase production and at the same time minimising N losses. Organic farming generally is assumed to be environmental-friendlier than conventional farming. Due to the prohibition of synthetic fertiliser, organic farming depends on organic fertilisers whose availability to crops depends on microbial mineralisation and immobilisation processes. Microbial biomass and activity is usually higher in organically than in conventionally managed cropping systems. Using the DOC long-term field experiment as a model we analysed the impact of the soil microbial biomass on N use efficiency of animal manure and mineral fertiliser and on the fate of fertiliser N not taken up by crops in an organic and a conventional cropping system. Despite higher microbial activity in the soil of the organically than the conventionally managed cropping system the fate of fertiliser N was the same in both cropping systems, as shown by similar fertiliser N use efficiency by crops and similar recovery of fertiliser-derived N in the soil. This suggests that the two cropping systems have the same potential to emit N compounds to the environment.