DOCSLIB.ORG

Mineralogy and Geochemistry of Soils of Ultramafic

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Mineralogy and Geochemistry of Soils of Ultramafic MINERALOGY AND GEOCHEMISTRY OF SOILS OF ULTRAMAFIC ORIGIN FROM THE GREAT DYKE, ZIMBABWE AND GILLESPIE COUNTY, TEXAS A Dissertation by COURAGE BANGIRA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY December 2010 Major Subject: Soil Science Mineralogy and Geochemistry of Soils of Ultramafic Origin from the Great Dyke, Zimbabwe and Gillespie County, Texas Copyright December 2010 Courage Bangira MINERALOGY AND GEOCHEMISTRY OF SOILS OF ULTRAMAFIC ORIGIN FROM THE GREAT DYKE, ZIMBABWE AND GILLESPIE COUNTY, TEXAS A Dissertation by COURAGE BANGIRA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved by: Chair of Committee, Richard. H. Loeppert Committee Members, Charles T. Hallmark Youjun Deng Alan E. Pepper Head of Department, David D. Baltensperger December 2010 Major Subject: Soil Science iii ABSTRACT Mineralogy and Geochemistry of Soils of Ultramafic Origin from the Great Dyke, Zimbabwe and Gillespie County, Texas. (December 2010) Courage Bangira, B.S., University of Zimbabwe; M.S., Gent University, Belgium Chair of Advisory Committee: Dr. Richard H. Loeppert Although soils developed from ultramafic parent materials have significance to agriculture, ecology and health, their bio-geochemistry is poorly understood. The mineralogical and bio-geochemistry of soils formed from the ultramafic parent materials of the Great Dyke, Zimbabwe and Gillespie County, Texas was investigated. The objectives were to determine the mineralogical and bio-geochemical properties of the soils in order to assess the potential impact and challenges to agriculture, and environmental quality. Soil samples were taken from the crest, shoulder, footslope and the toeslope. Chemical analyses were performed by nuclear and spectroscopic techniques. Mineral characterization was conducted by x-ray diffraction (XRD) and spectroscopic techniques. Microbial whole-community structure was determined by the fatty acid methyl esters (FAME) technique. The results indicate wide chemical and mineralogical compositions among the studied sites. The soils contain relatively high concentrations of heavy metals (some sites contain Cr(VI)), but low levels of K and Ca. The highest concentrations of trace metal were associated with chromite, Fe oxides and serpentinite. The concentrations of Mg were higher than those of Ca and varied between Zimbabwe and Texas soils largely due to the parent materials. Unique to these soils is the occurrence of talc, serpentine, chlorite, Fe-rich smectite, amphiboles, pyroxenes, Fe and Cr oxides in relatively large amounts. These soils also lack micas and have neglible amounts of kaolinite and feldspars. Palygorskite and serpentine occurred in specific soil horizons and at specific landscape positions. iv FAME profiles indicate that the soil microbial community structure is predominantly bacteria and fungi (including arbuscular mycorrhiza fungi) at each landscape position across the transect. Biomarkers for actinomycetes were undetectable. The proportions of Gram-positive bacteria were higher than those of the Gram-negative bacteria. Very low levels of nutrients (Ca and K), higher Mg/Ca molar ratios, and the relatively high concentrations of heavy metals in these soils impact agricultural productivity. High concentrations of heavy metals, the presence of the Cr(VI) as well as its great potential to form in these soils might impact microbial activity and environmental quality. The occurrence of fibrous minerals (e.g serpentine and amphiboles) in these soils will likely impact human health. v ACKNOWLEDGEMENTS I would like to thank my committee chair, Dr. Loeppert, and my committee members, Dr. Hallmark, Dr. Deng and Dr. Pepper, for their guidance and support throughout the course of this research. I am grateful to the Fulbright Scholarship and Tom Slick Fellowship, which provided financial support for part of this study. I would also like to thank Dr. W. James for assistance with neutron activation analysis; Dr. J.B. Dixon for the transmission electron microscopy analysis; Dr. J.W. Stucki for Mossbauer spectroscopy analysis; Dr. T. Gentry for assistance with microbial characterization and Ms D. Prochaska for some soil analyses. My appreciation goes to the staff and faculty in the Department of Soil Science and Agricultural Engineering, University of Zimbabwe for their assistance with sampling and sample shipment logistics. Many thanks go to Dr. M. Wuta, Mr. E. Nyakudya, Ms D. Chinamo, Mr. E. Chikwari and Mr. P. Mubvumba for their help with sampling and shipping logistics. Thanks also go to my friends and colleagues and the department faculty and staff for making my time at Texas A&M University a great experience. I would also like to thank my family for their encouragement and to my wife and children for patience and love. vi TABLE OF CONTENTS Page ABSTRACT .............................................................................................................. iii ACKNOWLEDGEMENTS ...................................................................................... v TABLE OF CONTENTS .......................................................................................... vi LIST OF FIGURES ................................................................................................... x LIST OF TABLES .................................................................................................... xv CHAPTER I INTRODUCTION ................................................................................ 1 Background and Literature Review ................................................ 2 Changing land use ................................................................. 4 Objectives ....................................................................................... 4 II MINERALOGICAL AND GEOCHEMICAL COMPOSITION OF SOIL OF ULTRAMAFIC ORIGIN FROM THE NORTHERN GREAT DYKE, ZIMBABWE ............................................................. 5 Introduction .................................................................................... 5 Agricultural, health and environmental challenges of ultramafic soils ..................................................................... 5 Materials and Methods ................................................................... 8 Study site .................................................................................. 8 Sampling protocol .................................................................... 8 Chemical analyses .................................................................... 8 Total elemental analysis by neutron activation analysis .......... 10 Selective dissolution of mineral phases ................................... 10 Mineral analyses ....................................................................... 11 Results and Discussion ................................................................... 12 Soil physical and chemical properties ..................................... 12 Total elemental composition ................................................... 14 Heavy metals extracted by DC, AO, and HH ......................... 15 Fe ..................................................................................... 15 vii CHAPTER Page Mn ................................................................................... 17 Cr ..................................................................................... 18 Ni ..................................................................................... 18 Occurrence of Cr (VI) in soils ............................................... 19 Mineral compositions of soils and parent rocks .................... 19 Mineralogy of the clay fractions ........................................... 20 Talc ................................................................................. 20 Serpentine ........................................................................ 25 Iron-rich smectite ............................................................ 27 Vermiculite and kaolinite ................................................ 27 Iron oxides ....................................................................... 28 Mineralogy of sand and silt fraction ..................................... 28 Enstatite ........................................................................... 28 Chlorite and serpentine .................................................... 30 Quartz .............................................................................. 31 Chromite .......................................................................... 31 Fe and Mn oxides ............................................................ 33 Spatial variation of soil minerals ........................................... 35 Comparison with other ultramafic soils ................................ 38 Implications .................................................................................... 39 Agriculture ............................................................................ 39 Environment and health ........................................................ 40 III MICROBIAL COMMUNITY STRUCTURE OF SOME SOILS ACROSS THE TRANSECT OF THE GREAT DYKE, ZIMBABWE. ....................................................................................... 41 Introduction .................................................................................... 41 Materials
Load more

Recommended publications
  • F Makwara (PDF)
    CHROMITE GEOLOGY OF ZIMBABWE AND RELATED MINING CHALLENGES PRESENTATION GREAT DYKE : MUTORASHANGA AUGUST 2017 2 WORLD CHROME RESOURCE Estimate World Chromite Resource : +-12 Billion Tonnes • South Africa : 72% of world Resource - Stratiform • Zimbabwe: 12% -Stratiform & podiform • Kazakhstan: 4% - Podiform • Finland : 2% -Podiform • India : 1% -Podiform • Turkey and others : 9% -Largely podiform But Zimbabwe companies producing at full capacity is not in the top 5 producing companies . STRATIFORM & PODIFORM GEOLOGY LOCATION GEOLOGY MAP - ZIMBABWE MASHONALAND CENTRAL MASHONALAND WEST CHIRUMANZU MIDLANDS MASVINGO MBERENGWA 5 LOCATION OF STRATIFORM CHROMITE RESOURCE • Mashonaland Central: North Dyke Tengenenge Impinge Birkdale Mutorashanga • Mashonaland West: Middle Dyke Ngezi Darwendale Maryland Lembe/Mapinga Mutorashanga • Midlands: South Dyke Lalapanzi Mapanzure Bannockburn CSC LOCATION OF PODIFORM CHROMITE RESOURCES • Midlands: Valley Nhema Chirumanzu Mberengwa • Masvingo: Mashava THE GREAT DYKE AND PODIFORMS GEOLOGY • THE GREAT DYKE • Tengenenge to Mberengwa, Location • Stretches for 550km and is 4-11km wide. • PODIFORM • Isolated chrome resources in Shurugwi,Mashava ,Nhema ,Valley, Chirumanzu and Mberengwa • THE DYKE : STRATIFORM • Chromite hosts rocks are :Harzburgite, dunite, serpentinite and pyroxenite Host Rock • PODIFORM • Chromite host rocks are: Serpentinite ,Silicified Talc Carbonate and Talc Carbonate • 10 known seams, The 11 th seam is poorly exposed in the North Dyke • 8cm to 40cm thickness Chrome Seams • Average vertical spacing of seams is 30-40m • Geotechnical Parameters considered fore seams are: Seam Widths, quality, dip, friability, & continuity • Platinum Group Metals Known Minerals in • Chrome the Dyke • Asbestos • Nickel 8 CHROMITE RESOURCES • The dyke intruded as an ultramafic sill ,estimated age 2.7 Ga . STRATIFORM • 11 seams are known to exist on the Great Dyke, but not evenly distributed through out the dyke.
    [Show full text]
  • California's Serpentine
    CALIFORNIA'S SERPENTINE by Art Kruckeberg Serpentine Rock Traditional teaching in geology tells us that rocks Californians boast of their world-class tallest and can be divided into three major categories—igneous, oldest trees, highest mountain and deepest valley; but metamorphic, and sedimentary. The igneous rocks, that "book of records" can claim another first for the formed by cooling from molten rock called magma, state. California, a state with the richest geological are broadly classified as mafic or silicic depending tapestry on the continent, also has the largest exposures mainly on the amount of magnesium and iron or silica of serpentine rock in North America. Indeed, this present. Serpentine is called an ultramafic rock because unique and colorful rock, so abundantly distributed of the presence of unusually large amounts of around the state, is California's state rock. For magnesium and iron. Igneous rocks, particularly those botanists, the most dramatic attribute of serpentine is that originate within the earth's crust, above the its highly selective, demanding influence on plant life. mantle, contain small but significant amounts of The unique flora growing on serpentine in California illustrates the ecological truism that though regional climate controls overall plant distribution, regional Views of the classic serpentine areas at New Idria in San Benito County. The upper photo was taken in 1932, the lower in 1960 geology controls local plant diversity. Geology is used of the same view; no evident change in 28 years. Photos here in its broad sense to include land forms, rocks courtesy of the U.S. Forest Service and Dr.
    [Show full text]
  • Mining Within Zimbabwe's Great Dyke: Extent , Impacts & Opportunities
    Mining Within Zimbabwe’s Great Dyke: Extent , Impacts & Opportunities Authors: Gilbert Makore & Veronica Zano Published by: Zimbabwe Environmental Law Association (ZELA) Sponsored by: International Alliance on Natural Resource in Africa (IANRA) Authors: Gilbert Makore and Veronica Zano Editor: Muduso Dhliwayo Copyright: 2012. Zimbabwe Environmental Law Association (ZELA) This publication may be reproduced in whole or in part and in any form for educational or non-profit uses, without special permission from the copyright holder, provided full acknowledgement of the source is made. No use of this publication may be made for resale or other commercial purposes without the prior written permission of ZELA. Year of Publication: 2012 Available from: Zimbabwe Environmental Law Association (ZELA), No. 6 London Derry Road, Eastlea, Harare, Zimbabwe: Tel: 253381; 252093, Email: , Website: www.zela.org Zimbabwe Environmental Law Association International Alliance on Natural Resource in Africa International Alliance on Natural Resources in Africa MINING WITHIN ZIMBABWE’S GREAT DYKE: EXTENT , IMPACTS AND OPPORTUNITIES I Table of Contents Executive Summary: 1 The Great Dyke Mineral Belt: 2 Mining and Mining Development Contribution to Economic Growth: 5 Companies operating in the Great Dyke: 10 Communities along the Great Dyke: 12 Impacts of Mining on the Great Dyke Communities: 14 Recommendations: 19 Conclusion: 20 MINING WITHIN ZIMBABWE’S GREAT DYKE: EXTENT , IMPACTS AND OPPORTUNITIES ii Executive Summary The Great Dyke is a seam of ore-bearing rock that goes from the north to the south of Zimbabwe. The Dyke spans a total length of 550kms and has a maximum width of 11kms. This geological feature represents an important resource for Zimbabwe's national economy and the local communities' livelihoods.
    [Show full text]
  • Chemical and Biochemical Properties of Soils Developed from Different Lithologies in Northwestern Spain (Galicia)
    Article Chemical and Biochemical Properties of Soils Developed from Different Lithologies in Northwestern Spain (Galicia) Valeria Cardelli 1,*, Stefania Cocco 1, Alberto Agnelli 2, Serenella Nardi 3, Diego Pizzeghello 3, Maria J. Fernández‐Sanjurjo 4 and Giuseppe Corti 1 1 Department of Agricultural, Food and Environmental Sciences, Università Politecnica delle Marche, Ancona, 60131, Italy; [email protected] (S.C.); [email protected] (G.C.) 2 Department of Agricultural, Food and Environmental Sciences, Università degli Studi di Perugia, Perugia, 06121, Italy; [email protected] 3 Department of Agronomy, Food, Natural Resources, Animals and the Environment, Università degli Studi di Padova, Legnaro, 35020, Italy; [email protected] (S.N.); [email protected] (D.P.) 4 Department of Soil and Agronomic Chemistry, Universidade de Santiago de Compostela, Lugo, 27001, Spain; [email protected] * Correspondence: [email protected]; Tel.: +39‐338‐599‐6867 Academic Editors: Adele Muscolo and Miroslava Mitrovic Received: 15 March 2017; Accepted: 19 April 2017; Published: 22 April 2017 Abstract: Physical and chemical soil properties are generally correlated with the parent material, as its composition may influence the pedogenetic processes, the content of nutrients, and the element biocycling. This research studied the chemical and biochemical properties of the A horizon from soils developed on different rocks like amphibolite, serpentinite, phyllite, and granite under a relatively similar climatic regime from Galicia (northwest Spain). In particular, the effect of the parent material on soil evolution, organic carbon sequestration, and the hormone‐like activity of humic and fulvic acids were tested. Results indicated that all the soils were scarcely fertile because of low concentrations of available P, exchangeable Ca (except for the soils on serpentinite and phyllite), and exchangeable K, but sequestered relevant quantities of organic carbon.
    [Show full text]
  • A Semi-Quantitative Model for the Formation of Great Dyke-Type Platinum Deposits
    A Semi-Quantitative Model for the Formation of Great Dyke-Type Platinum Deposits William P. Meurer1 and Alan E. Boudreau2 1Dept. of Geosciences, Univ. of Houston, 312 Sci. & Res. Bldg. 1, Houston, TX 77204-5007 2Div. Earth Sci., Nicholas School of the Env. and Earth Sci., Box 90227, Duke University, Durham, NC 27708 email: [email protected] The uppermost parts of the ultramafic 2) The PGE-sulfide mineralization is sections of some layered intrusions host significant commonly found below the ultramafic-mafic deposits of the platinum-group elements (PGE). contact. In addition, there are typically significant The type example of this class of PGE deposit is stratigraphic “offsets” between the maximum the Great Dyke of Zimbabwe. The Munni Munni concentrations of the PGE, base metals and sulfur. deposit has a similar occurrence (e.g., Hoatson and 3) At discrete horizons, just below the Keays, 1989). In the Stillwater Complex of ultramafic-mafic boundary, the rocks have higher Montana there are local shows of PGE-sulfide incompatible trace-element concentrations, greater enrichments at the top of the Ultramafic series but modal proportions of interstitial minerals, and more they are not laterally continuous (fig. 1). evolved mineral compositions. These features are These deposits have a number of common interpreted to reflect a marked enrichment in features: crystallized interstitial liquid in these rocks. 1) Each is characterized by a lower A number of investigators have suggested sequence of ultramafic rocks consisting mainly of that these zones are the result of a complex pyroxene and olivine overlain by mafic rocks interplay of extreme fractionation, magma mixing, containing 50 to 60 % plagioclase.
    [Show full text]
  • Transfer of Heavy Metals Through Terrestrial Food Webs: a Review
    Gall, et al. 2015. Published in Environmental Monitoring and Assessment. 187:201 Transfer of heavy metals through terrestrial food webs: areview Jillian E. Gall & Robert S. Boyd & Nishanta Rajakaruna Abstract Heavy metals are released into the environ- metal-tolerant insects, which occur in naturally high- ment by both anthropogenic and natural sources. Highly metal habitats (such as serpentine soils) and have adap- reactive and often toxic at low concentrations, they may tations that allow them to tolerate exposure to relatively enter soils and groundwater, bioaccumulate in food high concentrations of some heavy metals. Some webs, and adversely affect biota. Heavy metals also metallophyte plants are hyperaccumulators of certain may remain in the environment for years, posing long- heavy metals and new technologies using them to clean term risks to life well after point sources of heavy metal metal-contaminated soil (phytoextraction) may offer pollution have been removed. In this review, we compile economically attractive solutions to some metal pollu- studies of the community-level effects of heavy metal tion challenges. These new technologies provide incen- pollution, including heavy metal transfer from soils to tive to catalog and protect the unique biodiversity of plants, microbes, invertebrates, and to both small and habitats that have naturally high levels of heavy metals. large mammals (including humans). Many factors con- tribute to heavy metal accumulation in animals includ- Keywords Ecosystem health . Metal toxicity. Metal ing behavior, physiology, and diet. Biotic effects of hyperaccumulation . Bioaccumulation . Environmental heavy metals are often quite different for essential and pollution . Phytoremediation non-essential heavy metals, and vary depending on the specific metal involved.
    [Show full text]
  • The Plate Theory for Volcanism
    This article was originally published in Encyclopedia of Geology, second edition published by Elsevier, and the attached copy is provided by Elsevier for the author's benefit and for the benefit of the author’s institution, for non-commercial research and educational use, including without limitation, use in instruction at your institution, sending it to specific colleagues who you know, and providing a copy to your institution’s administrator. All other uses, reproduction and distribution, including without limitation, commercial reprints, selling or licensing copies or access, or posting on open internet sites, your personal or institution’s website or repository, are prohibited. For exceptions, permission may be sought for such use through Elsevier's permissions site at: https://www.elsevier.com/about/policies/copyright/permissions Foulger Gillian R. (2021) The Plate Theory for Volcanism. In: Alderton, David; Elias, Scott A. (eds.) Encyclopedia of Geology, 2nd edition. vol. 3, pp. 879-890. United Kingdom: Academic Press. dx.doi.org/10.1016/B978-0-08-102908-4.00105-3 © 2021 Elsevier Ltd. All rights reserved. Author's personal copy The Plate Theory for Volcanism Gillian R Foulger, Department of Earth Sciences, Science Laboratories, Durham University, Durham, United Kingdom © 2021 Elsevier Ltd. All rights reserved. Statement of Plate Theory 879 Background, History, Development and Discussion 879 Lithospheric Extension 880 Melt in the Mantle 881 Studying Intraplate Volcanism 882 Examples 883 Iceland 883 Yellowstone 885 The Hawaii and Emperor Volcano Chains 886 Discussion 888 Summary 888 References 888 Further Reading 889 Statement of Plate Theory The Plate Theory for volcanism proposes that all terrestrially driven volcanism on Earth’s surface, including at unusual areas such as Iceland, Yellowstone and Hawaii, is a consequence of plate tectonics.
    [Show full text]
  • Impact of Various Amendments on Immobilization and Phytoavailability of Nickel and Zinc in a Contaminated floodplain Soil
    Int. J. Environ. Sci. Technol. (2015) 12:2765–2776 DOI 10.1007/s13762-014-0713-x ORIGINAL PAPER Impact of various amendments on immobilization and phytoavailability of nickel and zinc in a contaminated floodplain soil S. M. Shaheen • J. Rinklebe • M. H. Selim Received: 15 April 2014 / Revised: 17 October 2014 / Accepted: 10 November 2014 / Published online: 4 December 2014 Ó Islamic Azad University (IAU) 2014 Abstract The immobilization of toxic metals in soils respectively. The addition of SBFL, CBD, and LS leads to using amendments is a cost-effective remediation tech- the highest decreasing rate of concentrations of Ni in plants nique for contaminated soils. Therefore, this study aimed to (56–68 %) and Zn (40–49 %). The results demonstrate the assess the efficiency of various amendments to immobilize high potential of CBD, SBFL, LS, BE, AC, and BI for the nickel (Ni) and zinc (Zn) in soil and reduce their phyto- immobilization of Ni and Zn in contaminated floodplain availability. A greenhouse pot experiment was established soils. with a contaminated agricultural floodplain soil. The soil was treated with activated carbon (AC), bentonite (BE), Keywords Low-cost immobilizing agents Á Nano- biochar (BI), cement bypass kiln dust (CBD), chitosan hydroxyapatite Á Organo-clay Á Rapeseed Á Remediation Á (CH), coal fly ash (FA), limestone (LS), nano-hydroxyap- Toxic metals atite (HA), organo-clay (OC), sugar beet factory lime (SBFL), and zeolite (Z) with an application rate of 1 % (0.2 % for HA) and cultivated by rapeseed (Brassica na- Introduction pus). After plant harvesting, the soil was analyzed for water-soluble and geochemical fractions of Ni and Zn.
    [Show full text]
  • Plate Tectonics on Early Earth? Weighing the Paleomagnetic Evidence
    spe440-12 3rd pages The Geological Society of America Special Paper 440 2008 Plate tectonics on early Earth? Weighing the paleomagnetic evidence David A.D. Evans* Department of Geology & Geophysics, Yale University, New Haven, Connecticut 06520-8109, USA Sergei A. Pisarevsky* School of GeoSciences, University of Edinburgh, Edinburgh EH9 3JW, Scotland, UK ABSTRACT Paleomagnetism is the only quantitative method available to test for lateral motions by tectonic plates across the surface of ancient Earth. Here, we present several analyses of such motions using strict quality criteria from the global paleomagnetic database of pre–800 Ma rocks. Extensive surface motion of cratons can be documented confi dently to older than ca. 2775 Ma, but considering only the most reliable Archean data, we cannot discern differential motion from true polar wander (which can also generate surface motions relative to the geomagnetic reference frame). In order to fi nd evidence for differential motions between pairs of Precambrian cratons, we compared distances between paleomagnetic poles through precisely isochronous intervals for pairs of cra- tons. The existing database yields several such comparisons with ages ranging from ca. 1110 to ca. 2775 Ma. Only one pair of these ages, 1110–1880 Ma, brackets signifi cantly different apparent polar wander path lengths between the same two cratons and thus demonstrates differential surface motions. If slightly less reliable paleomagnetic results are considered, however, the number of comparisons increases dramatically, and an example is illustrated for which a single additional pole could constrain differential cratonic motion into the earliest Paleoproterozoic and late Neoarchean (in the interval 2445–2680 Ma).
    [Show full text]
  • Non Commercial Use Only
    IJA-2017_2.qxp_Hrev_master 10/07/17 10:50 Pagina 161 Italian Journal of Agronomy 2017; volume 12:794 Crop response to soils amended with biochar: expected benefits and unintended risks Raghunath Subedi, Chiara Bertora, Laura Zavattaro, Carlo Grignani Department of Agricultural, Forest and Food Sciences, University of Turin, Grugliasco (TO), Italy Abstract Introduction Biochar (BC) from biomass waste pyrolysis has been widely In the agricultural sector, the term biochar (BC) is acknowl- studied due to its ability to increase carbon sequestration, reduce edged as a tool for soil management and carbon (C) sequestration greenhouse gas emissions, and enhance both crop growth and soil (Barrow, 2012; Jeffery et al., 2015b; Smith, 2016). It is a solid quality. This review summarises the current knowledge of BC pro- material, rich in recalcitrant C, derived from anaerobic heating of duction, characterisation, and types, with a focus on its positive biomass such as wood, manure, sludge, or crop residue (Lehmann effects on crop yield and soil properties vs the unintended risks asso- and Joseph, 2015). The use of BC for soil C sequestration fol- ciated with these effects. Biochar-amended soils enhance crop lowed the discovery of so-called terra preta, the charcoal-rich and growth and yield via several mechanisms: expanded plant nutrient highly fertile soil of the central Amazon basin (Barrow, 2012). and water availability through increased use efficiencies, improved Biochar, a secondary product of pyrolysis after syngas and bio-oil soil quality, and suppression of soil and plant diseases. Yield production for bioenergy (Srinivasan et al., 2015; Jeffery et al., response to BC has been shown to be more evident in acidic and 2015b), is touted for its diverse and positive agricultural roles.
    [Show full text]
  • Soil Patterns in Three Darlingtonia Fens Of
    RESEARCH ARTICLE ABSTRACT: The Darlingtonia fens, found on serpentine soils in southern Oregon, are distinct commu­ nities that demonstrate a balance among high water tables, shallow soils, the presence of heavy metals, and limited nutrients. While conservative efforts have been made to preserve them, soil patterning or the specific processes that appear to underlie soil variability are poorly understood. I investigated the relationship of fire-free period on soil gradients and succession in three Darlingtonia fens, each with a different amount of time since last fire. Changes in vegetation and belowground variables were distin­ • guished across fen, savanna, and shrub communities and across the three sites. I suggest that belowground gradients may be more important than time since fire at preserving these uniquely adapted systems, Soil Patterns in Three since vegetation undergoes post fire succession from fen to shrub to savanna after approximately 100 years since fire. Although restoration of ecosystem structure and processes was not the primary focus of this study, my data suggest that time since fire may drive ecosystem processes in a trajectory away Darlingtonia Fens from the normal succession cycle and that soil moisture decreases and nitrogen levels increase with an increase in fire-free period. of Southwestern Index terms: Darlingtonia fen, Jeffrey pine savanna, soil ammonium, soil gradients Oregon INTRODUCTION of an intermediate stature such as shrubs (Whittaker 1960). Although a number of Deborah A. Tolman 1 Soil gradients in terrestrial ecosystems are rare plant species are common to these Portland State University often conceptualized as having discrete communities, the dominant understory P.O .Box 751 but mutually dependent above and below­ species includes the carnivorous plants Portland, Oregon, 97207-0751 ground components (Smith et al.
    [Show full text]
  • Ecological and Evolutionary Consequences Of
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by D-Scholarship@Pitt ECOLOGICAL AND EVOLUTIONARY CONSEQUENCES OF PLANT GROWTH ON SERPENTINE SOIL: EFFECTS OF SOIL METALS ON PLANT MORPHOLOGY, METAL ACCUMULATION, PLANT-POLLINATOR INTERACTIONS, AND POLLEN- PISTIL INTERACTIONS by George A. Meindl BS, Humboldt State University, 2007 MA, Humboldt State University, 2009 Submitted to the Graduate Faculty of the Kenneth P. Dietrich School of Arts and Sciences in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Biological Sciences University of Pittsburgh 2014 UNIVERSITY OF PITTSBURGH KENNETH P. DIETRICH SCHOOL OF ARTS AND SCIENCES This dissertation was presented by George A. Meindl It was defended on November 3, 2014 and approved by Dr. Daniel Bain, Dept. of Geology and Planetary Science, University of Pittsburgh Dr. Walter Carson, Dept. of Biological Sciences, University of Pittsburgh Dr. Susan Kalisz, Dept. of Biological Sciences, University of Pittsburgh Dr. Rick Relyea, Dept. of Biological Sciences, University of Pittsburgh Dissertation Advisor: Dr. Tia-Lynn Ashman, Dept. of Biological Sciences, University of Pittsburgh ii Copyright © by George A. Meindl 2014 iii ECOLOGICAL AND EVOLUTIONARY CONSEQUENCES OF PPLANTLANT GROWTH ON SERPENTINE SOIL: EFFECTS OF SOIL METALS ON PLANT MORPHOLOGY, METAL ACCUMULATION, PLANT-POLLINATOR INTERACTIONS, AND POLLEN-PISTIL INTERACTIONS George A. Meindl, PhD University of Pittsburgh, 2014 Edaphic factors are a strong selective force in shaping both plant species distributions and the diversification of many lineages. Specifically, adaptation to novel soil environments can result in species-level changes in floral morphology, phenology, or chemistry, each of which may affect plant reproduction.
    [Show full text]