Download or read book Non linear Nitrogen Dynamics and Calcium Depletion Along a Temperate Forest Soil Nitrogen Gradient written by Emily R. Sinkhorn and published by . This book was released on 2008 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding how N availability influences base cation stores is critical for long-term ecosystem sustainability. Indices of nitrogen (N) availability and the distribution of nutrients in plant biomass, soil, and soil water were examined across ten young, unpolluted Douglas-fir (Pseudotsuga menziesii) stands in the Oregon Coast Range spanning a three-fold soil N gradient (0-10 cm: 0.21 - 0.69% N, 0-100 cm: 9.2 - 28.8 Mg N . ha−1 but having similar stand age and sandstone parent material. [delta]15N in foliage and forest floor increased across the gradient and approached the isotopic signature of the atmosphere at high soil N stands, suggesting that variation in N accumulation across sites is related to historic site occupancy by N2−fixing red alder (Alnus rubra). Although no longer present on these sites, red alder stands can add 100-200 kg N ha−1 yr−1to an ecosystem for decades, a significantly higher N input than precipitation (0.65 kg N ha−1yr−1). Annual net N mineralization and litterfall N return displayed non-linear relationships with soil N, increasing initially, and then decreasing at more N-rich sites. In contrast, nitrate leaching from deep soils increased linearly across the soil N gradient and ranged from 0.074 to 30 kg N . ha−1yr−1). Nitrogen availability was negatively correlated with indices of Ca availability. Soil exchangeable Ca, Mg, and K pools to 1 m depth were negatively related to nitrate losses across sites. Calcium was the only base cation that decreased in both plant and soil pools across the soil N gradient, and a greater proportion of total available ecosystem Ca was sequestered in plant biomass at high N, low Ca sites. The preferential storage of Ca in aboveground biomass at high N and low Ca sites, while critical for sustaining plant productivity, may also predispose forests to Ca depletion in areas managed for intensive biomass removal. Our work supports a hierarchical model of coupled N-Ca cycles across gradients of soil N enrichment, with microbial production of mobile nitrate leading to depletion of readily available Ca at the ecosystem scale, and plant sequestration promoting Ca conservation as Ca supply diminishes. Long-term N enrichment of temperate forest soils appears capable of sustaining an open N cycle and key symptoms of N saturation for multiple decades after the cessation of elevated N inputs.

Download or read book Soil Nitrogen Cycling Over Two Decades Following Calcium Treatment in Hubbard Brook Experimental Forest NH written by and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A watershed-scale calcium addition experiment at Hubbard Brook Experimental Forest, New Hampshire, was performed in 1999 to better understand how forest ecosystem function and biogeochemistry are affected by changes in pH. Significant increases in forest growth and acid neutralizing capacity of the soil and stream water were reported in the six years following the calcium addition, but the expected stimulation of the nitrogen cycle was not observed. The aims of this study were to 1) examine the 20-year dataset of soil nitrogen dynamics following the experimental calcium addition in the treated watershed and paired reference area to understand longer term trends and effects, and 2) explore connections between soil nitrogen processes and watershed nitrogen export in stream water observed in the calcium-treated watershed since 2013. Since 2002, soil pH was higher in the calcium-treated watershed than the reference, with stronger differences seen in surface horizons, but declined over time and converged toward the reference conditions by 2018, throughout the soil profile. Soil nitrogen cycling measurements were not consistent with the changes in soil pH, and temporal trends were different depending on the variable in question. Differences in temporal trends in nitrogen cycling variables were often more pronounced as a function of soil horizon than Ca treatment. However, interesting trends were seen in certain variables, with effects of Ca treatment diverging from long term trends in the reference area for some variables while converging toward reference conditions for others. There was no strong evidence from microbial nitrogen transformations at the plot scale to explain the nitrate export from the calcium treated watershed observed by other researchers (Rosi-Marshall et al. 2016). Because pathways in soil nitrogen cycling did not show consistent trajectories over time in response to the calcium treatment, understanding how changes in pH and other environmental variables, along with competition for nitrogen between plants and soil microbes, differentially affect these various processes remains a challenge in forest ecosystem science.

Download or read book Nitrogen Deposition Effects on Soil Carbon Dynamics in Temperate Forests written by Shimon Ozeri Ginzburg and published by . This book was released on 2014 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Seasonal Dynamics of Soil Nitrogen in Temperate Forests Affected by Anthropogenic Nitrogen Deposition written by Kara Kinser Borden and published by . This book was released on 2007 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Carbon and Nitrogen Dynamics in Temperate Forest Floors written by Margaret Mary Harris and published by . This book was released on with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissolved Organic Nitrogen DON Cycling Along a Temperate Forest Nitrogen Availability Gradient written by Emily Elizabeth Scott and published by . This book was released on 2012 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Linking Carbon Nitrogen and Calcium Cycling in Northeastern U S Forests written by April Marin Melvin and published by . This book was released on 2012 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon (C), nitrogen (N), and calcium (Ca) cycling in forest ecosystems is controlled largely by the recycling of organic matter by biota and by the balance of new inputs and losses. In the northeastern U.S., the availability of these elements has been dramatically altered by human activities. Acid deposition has increased N inputs and caused declines in soil Ca concentrations. Concurrently, atmospheric carbon dioxide concentrations are rising. My dissertation research focused on understanding how individual tree species influence ecosystem C, N, and Ca cycling, and how increasing soil Ca by liming affects C and N pools, fluxes, and dissolved organic matter retention. In chapter 1, I show how Norway spruce, red oak, and sugar maple planted in a common garden influence soil C, N, and Ca pools. Norway spruce had the largest C and N stocks in the forest floor and upper mineral soils. No differences among species were observed in soil exchangeable Ca availability. Red oak plots displayed the highest foliar litter lignin concentrations, the shortest residence time for C and N in the forest floor, and the highest earthworm densities. This suggests that leaf litter recalcitrance is not the dominant driver of decomposition in this forest and that other factors, such as the presence of earthworms, can influence organic matter turnover in ways that are unexpected when only considering litter chemistry. In chapters 2 and 3, I discuss the long-term effects of liming on ecosystem C and N dynamics. Twenty years after lime addition, there was no evidence of a tree response. Within the forest floor, C and N stocks in limed soils were double that found in controls. I observed reductions in both soil basal respiration and net N mineralization, indicating that liming has altered C and N cycling within this ecosystem. I also investigated how soil exchangeable Ca concentrations influence dissolved organic C and N retention. Soils higher in exchangeable Ca tended to release less C and N, suggesting that liming may facilitate Ca-organic matter bridging, thereby reducing C and N losses from the upper mineral soils.

Download or read book The Effects of Nitrogen Deposition on Plant Community Dynamics in a Heterogeneous Savanna Landscape written by Elise M. Tulloss and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Urbanization and agricultural intensification in California has increased N emissions and, consequently, deposition to adjacent oak savanna landscapes. The total amount and chemical form of this deposition varies across the landscape at multiple spatial scales and through time. At a coarse scale, there is a non-linear gradient in N deposition across the California oak savanna region such that savanna sites closest to sources of N emissions receive greater deposition than sites in more remote areas. At a fine scale within savanna sites, a strong research foundation in oak woodland systems has described heterogeneity in soil resources created by the existence of oak canopies. This phenomenon, termed islands of fertility, is a net result of enhanced nutrient inputs and retention facilitated by the tree, with nitrogen deposition being recently suggested as a primary cause of enhanced inputs. The interaction between the regional-scale gradient of N deposition, the local-scale island of fertility, and the seasonal variability of N deposition results in heterogeneous soil N resources. Nitrogen availability is greatest beneath oaks and at sites on the high end of the regional gradient and during seasonal pulses of N deposition associated with precipitation events. These heterogeneous soil N resources play a critical role in structuring plant communities under current and increased N deposition. The aim of this dissertation was to investigate how N deposition varies at multiple scales depending on specific landscape drivers, such as site context and vegetation structure, and tease apart the effect of that heterogeneous N deposition on native and exotic competitive dynamics relative to multiple controlling factors. I quantified a gradient of N deposition across 6 oak savanna sites in north-central California. At the regional scale, sites closer to pollutant emissions received greater N deposition and sites in remote areas received less. At the local, within-site scale, the oak canopy was a hotspot of higher N deposition. The magnitude of the hotspot effect beneath oaks was not constant across the regional gradient, but rather oaks at the high end of the regional gradient received proportionally more N deposition than oaks at the low end of the gradient. This finding emphasized the importance of landscape context to within-site dynamics. The N deposition gradient was complex because several other soil and climate variables co-varied. Subsequent research was designed to experimentally tease apart the relative effect of N deposition on plant community dynamics from other factors that varied across this complex gradient, including soil type, which varied across the regional scale, and light availability, which varied between canopy and open areas at the local scale. A greenhouse experiment examined competitive interactions among native and exotic grasses in response to N fertilization, soil type, and light availability. Native and exotic grasses were both most sensitive to N deposition during the period of rapid vegetative growth in early spring. Invasive exotic grass was not becoming competitively dominant under increased N. Overall, N increased plant biomass, height, and seed mass altering the outcome of species interactions in a few cases, and thus, was important not as a single driving factor, but rather in the context of the other environmental factors I manipulated. This result indicated that N deposition must be considered together with the complex suite of environmental factors to predict effects to plant communities. In advancing our understanding of landscape and ecosystem ecology, the dissertation research highlighted the importance of landscape context and complex interactions among spatially and temporally heterogeneous factors in influencing dynamics within wildlands.

Download or read book Carbon and Nitrogen Dynamics from Slow Pools of Soil Organic Matter in a Temperate Forest written by Fernanda Santos and published by . This book was released on 2015 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Developments in forest soil nitrogen dynamics written by Mike Hornung and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Tree Chemistry Database written by and published by . This book was released on 2005 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Fernow Watershed Acidification Study written by Mary Beth Adams and published by BoD – Books on Demand. This book was released on 2006-04-28 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Fernow Watershed Acidification Study is a long-term, paired watershed acidification study. This book describes the responses to chronic N and S amendments by deciduous hardwood forests, one of the few studies to focus on hardwood forest ecosystems. Intensive monitoring of soil solution and stream chemistry, along with measurements of soil chemistry, and vegetation growth and chemistry, provide insights into the acidification process in forested watersheds.

Download or read book Manganese in Soils and Plants written by R.D. Graham and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sixty years ago at the Waite Agricultural Research Institute, G. Samuel, a plant pathologist, and C. S. Piper, a chemist, published their conclusion that the cause of roadside take-all, a disease of oats, was manganese deficiency. This report, together with the concurrent and independent studies of W. M. Carne in Western Australia were the first records of manganese deficiency in Australia and came only six years after McHargue's paper which is generally accepted as the final proof of the essentiality of this element. There must have been a few doubts for some people at the time, however, as the CAB publication, 'The Minor Elements of the Soil' (1940) expressed the view that further evidence to this effect was provided by Samuel and Piper. Their historic contributions are recognised by the International Symposium on Manganese in Soils and Plants as it meets on the site of their early labours to celebrate the 60th anniversary. This year Australians also acknowledge 200 years of European settlement in this country and so the Symposium is both a Bicentennial and a diamond jubilee event which recognises the impact of trace elements on agricultural development in Australia. In a broader sense, a symposium such as this celebrates, as it reviews, the efforts of all who over the ages have contributed to our knowledge of manganese in soils and plants.

Download or read book The Soils of Europe written by Walter L. Kubiena and published by . This book was released on 1953 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Methods of Soil Analysis Part 2 written by Richard W. Weaver and published by ACSESS. This book was released on 1994 with total page 1164 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil sampling for microbiological analysis; Statistical treatment of microbial data; Soil sterilization; Soil water potencial; Most probable number counts; Light microscopic methods for studying soil microorganisms; Viruses; Recovery and enumeration of viable bacteria; Coliform bacteria; Autotrophic nitrifying bacteria; Free-living dinitrogen-fixing bacteria; Legume nodule symbionts; Anaerobic bacteria and processes; Denitrifiers; Actiomycetes; Frankia and the actinorhizal symbiosis; Filamentous fungi; Vesicular-arbuscular mycorrhizal fungi; Isolation of microorganisms producting antibiotics; Microbiological procedures for biodegradation research; Algae and cyanobacteria; Marking soil bacteria with lacZY; Detection of specific DNA sequences in environmental sample via polymerase chaim reaction; Isolation and purification of bacterial DNA from soil; Microbial biomass; Soil enzymes; Carbon mineralization; Isotopic methods for the study of soil organic matter dynamics ; Practical considerations in the use of nitrogen tracers in agricultural and environmental research; Nitrogen availability; Nitrogen mineralization, immobilization, and nitrification; Dinitrogen fixation; Measuring denitrification in the field; Sulfur oxidation and reduction in soils; Iron and manganese oxidation and reduction.

Download or read book Trees Crops and Soil Fertility written by G. Schroth and published by CABI. This book was released on 2003-02-19 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation. Successful agroforestry requires an understanding of the complex relationship between trees, crops and soils. This book provides a review of both economic and biophysical aspects of soil use and research in agroforestry, with an emphasis on nutrient-poor forest and savanna soils. Key topics covered include the economics of soil fertility management, cycling of water, nutrients and organic matter, soil structure, and soil biological processes. The book combines synthetic overviews of research results and a review of methods used in research.From the foreword: 2The book is written within a particular context - soil fertility development under agroforestry. At first this may seem very specific and thus limited in appeal and application. But over the last decade or so agroforestry research has been one of the most influential in developing new insights into soil biology and fertility and thus provides a very suitable framework for review of progress. Furthermore the influence of trees on soil is profound and of significance beyond agroforestry systems, so the book is likely to be of interest in the wider spheres of agriculture, forestry and ecological sciences.3 Mike Swift, TSBF, Nairobi, Kenya.

Download or read book Litter Decomposition a Guide to Carbon and Nutrient Turnover written by and published by Academic Press. This book was released on 2005-11-22 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: Litter Decomposition describes one of the most important processes in the biosphere - the decay of organic matter. It focuses on the decomposition process of foliar litter in the terrestrial systems of boreal and temperate forests due to the greater amount of data from those biomes. The availability of several long-term studies from these forest types allows a more in-depth approach to the later stages of decomposition and humus formation. Differences between the decay of woody matter and foliar litter is discussed in detail and a different pattern for decomposition is introduced. While teachers and students in more general subjects will find the most basic information on decomposition processes in this book, scientists and graduate students working on decomposition processes will be entirely satisfied with the more detailed information and the overview of the latest publications on the topic as well as the methodological chapter where practical information on methods useful in decomposition studies can be found. Abundant data sets will serve as an excellent aid in teaching process and will be also of interest to researchers specializing in this field as no thorough database exists at the moment. Provides over 60 tables and 90 figures Offers a conceptual 3-step model describing the different steps of the decomposition process, demonstrating changes in the organic-chemical structure and nutrient contents Includes a synthesis of the current state of knowledge on foliar litter decomposition in natural systems Integrates more traditional knowledge on organic matter decomposition with current problems of environmental pollution, global change, etc. Details contemporary knowledge on organic matter decomposition