Soils and Decomposition Introductory Article
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
The Effects of Detritus Input on Soil Organic Matter Content and Carbon Dioxide Emission in a Central European Deciduous Forest
Acta Silv. Lign. Hung., Vol. 7 (2011) 87–96 The Effects of Detritus Input on Soil Organic Matter Content and Carbon Dioxide Emission in a Central European Deciduous Forest a* b c István FEKETE – Zsolt KOTROCZÓ – Csaba VARGA – b b Zsuzsa VERES – János Attila TÓTH a Institute of Environmental Science, College of Nyíregyháza, Nyíregyháza, Hungary b Department of Ecology, University of Debrecen, Debrecen, Hungary c Department of Land and Environmental Management, College of Nyíregyháza, Nyíregyháza, Hungary Abstract – A major objective of our research was to survey soil biological activity and organic matter content reduction in a Central European oak forest during treatments of various detritus inputs within the Síkf őkút DIRT ( Detritus Input and Removal Treatments ) Project. Beside the control, three detritus removal and two detritus duplication treatments were applied. Our examinations have proven that soil organic matter content declined relatively fast in detritus removal treatments. The reduction was especially remarkable in root detritus removal treatments, where – due to the lack of transpiration – soils were moister during the whole year than in the other treatments. The higher moisture content, despite of the reduction of detritus input, produced an intense soil respiration. This can be explained by the fact that decomposing organisms have increased the use of soil organic matter. Detritus input reduction had a significantly greater effect on soil respiration and organic matter content than detritus input duplication of the same extent. The latter did not cause any significant change compared to the control. litter manipulation / soil respiration / DIRT Project / humus content / climate change Kivonat – Az avarinput hatása a talaj szerves anyag tartalmára és szén-dioxid kibocsátására egy Közép-európai lombhullató erd őben. -
Basic Soil Science W
Basic Soil Science W. Lee Daniels See http://pubs.ext.vt.edu/430/430-350/430-350_pdf.pdf for more information on basic soils! [email protected]; 540-231-7175 http://www.cses.vt.edu/revegetation/ Well weathered A Horizon -- Topsoil (red, clayey) soil from the Piedmont of Virginia. This soil has formed from B Horizon - Subsoil long term weathering of granite into soil like materials. C Horizon (deeper) Native Forest Soil Leaf litter and roots (> 5 T/Ac/year are “bio- processed” to form humus, which is the dark black material seen in this topsoil layer. In the process, nutrients and energy are released to plant uptake and the higher food chain. These are the “natural soil cycles” that we attempt to manage today. Soil Profiles Soil profiles are two-dimensional slices or exposures of soils like we can view from a road cut or a soil pit. Soil profiles reveal soil horizons, which are fundamental genetic layers, weathered into underlying parent materials, in response to leaching and organic matter decomposition. Fig. 1.12 -- Soils develop horizons due to the combined process of (1) organic matter deposition and decomposition and (2) illuviation of clays, oxides and other mobile compounds downward with the wetting front. In moist environments (e.g. Virginia) free salts (Cl and SO4 ) are leached completely out of the profile, but they accumulate in desert soils. Master Horizons O A • O horizon E • A horizon • E horizon B • B horizon • C horizon C • R horizon R Master Horizons • O horizon o predominantly organic matter (litter and humus) • A horizon o organic carbon accumulation, some removal of clay • E horizon o zone of maximum removal (loss of OC, Fe, Mn, Al, clay…) • B horizon o forms below O, A, and E horizons o zone of maximum accumulation (clay, Fe, Al, CaC03, salts…) o most developed part of subsoil (structure, texture, color) o < 50% rock structure or thin bedding from water deposition Master Horizons • C horizon o little or no pedogenic alteration o unconsolidated parent material or soft bedrock o < 50% soil structure • R horizon o hard, continuous bedrock A vs. -
Fractionation and Characterization of Natural Organic Matter from Certain Rivers and Soils by Free-Flow Electrophoresis
Fractionation and Characterization of Natural Organic Matter from Certain Rivers and Soils by Free-Flow Electrophoresis GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1817-E Fractionation and Characterzation of Natural Organic Matter from Certain Rivers and Soils by Free-Flow Electrophoresis By J. A. LEENHEER and R. L. MALCOLM ORGANIC SUBSTANCES IN WATER GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1817-E UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1973 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Library of Congress catalog-card No. 73-600209 For sale by the Superintendent of Documents, U. S. Government Printing Office Washington, D. C. 20402 - Price 35 cents (paper cov«?r) Stock No. 2401-02400 CONTENTS Page Abstract ___________________________________________ El Introduction __________________________________ __ 1 Methods and materials __________________________________ 3 Sample preparation ______ _______ _ __ 3 Sample description _________________________________ 3 Separation procedure _______ ___________ __ 4 Assay of fractions ___________________________________ 4 Results and discussion _ _______________ 5 Conclusions ________________________________________ 12 References _____________________________________ __ 14 ILLUSTRATIONS Page FIGURES 1-3. Graphs showing: 1. Organic-carbon and optical-density electrophoretic fraction- ation curves for organic materials from soil and from river water ___________________________ E6 2. Organic-carbon and polysaccharide electrophoretic -
Terrestrial Decomposition
Terrestrial Decomposition • Objectives – Controls over decomposition • Litter breakdown • Soil organic matter formation and dynamics – Carbon balance of ecosystems • Soil carbon storage 1 Overview • In terrestrial ecosystems, soils (organic horizon + mineral soil) > C than in vegetation and atmosphere combined 2 Overview • Decomposition is: 1. Major pathway for C loss from ecosystems 2. Central to ecosystem C loss and storage 3 Overview 4 Incorporation 1 year later Overview • Predominant controls on litter decomposition are fairly well constrained 1. Temperature and moisture 2. Litter quality • N availability • Lignin concentration • Lignin:N • Mechanisms for soil organic matter stabilization: 1. Recalcitrance (refers to chemistry) 2. Physical protection • Within soil aggregates • Organo-mineral associations 3. Substrate supply regulation (energetic limitation) 5 Overview • Disturbance can override millenia in a matter of days or years: 1. Land use change 2. Invasive species 3. Climate change • Understanding the mechanistic drivers of decomposition, soil organic matter formation, and carbon stabilization help us make management decisions, take mitigation steps, and protect resources. 6 Overview Native Ōhiʻa - Koa forest Conversion to Reforestation in grass-dominated pasture (80 yr) Eucalyptus plantation (10 yr) Conventional sugar cane harvest. 20° C 18° C 16° C 14° C 7 Sustainable ratoon harvest. Decomposition • Decomposition is the biological, physical and chemical breakdown of organic material – Provides energy for microbial growth -
Determining the Fraction of Organic Carbon RISC Nondefault Option
Indiana Department of Environmental Management Office of Land Quality 100 N. Senate Indianapolis, IN 46204-2251 GUIDANCE OLQ PH: (317) 232-8941 Indiana Department of Environmental Management Office of Land Quality Determining the Fraction of Organic Carbon RISC Nondefault Option Background Soil can be a complex mixture of mineral-derived compounds and organic matter. The ratios of each component can vary widely depending on the type of soil being investigated. Soil organic matter is a term used by agronomists for the total organic portion of the soil and is derived from decomposed plant matter, microorganisms, and animal residues. The decomposition process can create complex high molecular weight biopolymers (e.g., humic acid) as well as simpler organic compounds (decomposed lignin or cellulose). Only the simpler organic compounds contribute to the fraction of organic carbon. There is not a rigorous definition of the fraction of organic carbon (Foc). However, it can be thought of as the portion of the organic matter that is available to adsorb the organic contaminants of concern. The higher the organic carbon content, the more organic chemicals may be adsorbed to the soil and the less of those chemicals will be available to leach to the ground water. A nondefault option in the Risk Integrated System of Closure (RISC) is to use Foc in the Soil to Ground Water Partitioning Model to calculate a site specific migration to ground water closure level. In the Soil to Ground Water Partition Model, the coefficient, Kd, for organic compounds is the Foc multiplied by the chemical-specific soil organic carbon water partition coefficient, Koc. -
Slope Stability Back Analysis Using Rocscience Software
Slope Stability Back Analysis using Rocscience Software A question we are frequently asked is, “Can Slide do back analysis?” The answer is YES, as we will discover in this article, which describes various methods of back analysis using Slide and other Rocscience software. In this article we will discuss the following topics: Back analysis of material strength using sensitivity or probabilistic analysis in Slide Back analysis of other parameters (e.g. groundwater conditions) Back analysis of support force for required factor of safety Manual and advanced back analysis Introduction When a slope has failed an analysis is usually carried out to determine the cause of failure. Given a known (or assumed) failure surface, some form of “back analysis” can be carried out in order to determine or estimate the material shear strength, pore pressure or other conditions at the time of failure. The back analyzed properties can be used to design remedial slope stability measures. Although the current version of Slide (version 6.0) does not have an explicit option for the back analysis of material properties, it is possible to carry out back analysis using the sensitivity or probabilistic analysis modules in Slide, as we will describe in this article. There are a variety of methods for carrying out back analysis: Manual trial and error to match input data with observed behaviour Sensitivity analysis for individual variables Probabilistic analysis for two correlated variables Advanced probabilistic methods for simultaneous analysis of multiple parameters We will discuss each of these various methods in the following sections. Note that back analysis does not necessarily imply that failure has occurred. -
Soil and Rock Properties
Soil and rock properties W.A.C. Bennett Dam, BC Hydro 1 1) Basic testing methods 2) Soil properties and their estimation 3) Problem-oriented classification of soils 2 1 Consolidation Apparatus (“oedometer”) ELE catalogue 3 Oedometers ELE catalogue 4 2 Unconfined compression test on clay (undrained, uniaxial) ELE catalogue 5 Triaxial test on soil ELE catalogue 6 3 Direct shear (shear box) test on soil ELE catalogue 7 Field test: Standard Penetration Test (STP) ASTM D1586 Drop hammers: Standard “split spoon” “Old U.K.” “Doughnut” “Trip” sampler (open) 18” (30.5 cm long) ER=50 ER=45 ER=60 Test: 1) Place sampler to the bottom 2) Drive 18”, count blows for every 6” 3) Recover sample. “N” value = number of blows for the last 12” Corrections: ER N60 = N 1) Energy ratio: 60 Precautions: 2) Overburden depth 1) Clean hole 1.7N 2) Sampler below end Effective vertical of casing N1 = pressure (tons/ft2) 3) Cobbles 0.7 +σ v ' 8 4 Field test: Borehole vane (undrained shear strength) Procedure: 1) Place vane to the bottom 2) Insert into clay 3) Rotate, measure peak torque 4) Turn several times, measure remoulded torque 5) Calculate strength 1.0 Correction: 0.6 Bjerrum’s correction PEAK 0 20% P.I. 100% Precautions: Plasticity REMOULDED 1) Clean hole Index 2) Sampler below end of casing ASTM D2573 3) No rod friction 9 Soil properties relevant to slope stability: 1) “Drained” shear strength: - friction angle, true cohesion - curved strength envelope 2) “Undrained” shear strength: - apparent cohesion 3) Shear failure behaviour: - contractive, dilative, collapsive -
Humus-Producing Materials and the Making and Use of Compost
174 August, 1926 No seed of the Carolina clover is available commercially; but where it is abundant, seedheads can readily be gathered and scattered where wanted. Seed of the low hop clover is not to be had in quan- tity, but that of the least hop clover can be bought in England under the name suckling clover or Trifolium minus. It can also be had from certain seed dealers in Oregon, who clean it out of alsike clover seed; but the Oregon seed is usually quite foul with weed seeds and there is at present no information as to how these weeds will behave in the East. Seeding of all of these clovers should be done in early fall or late summer. Much of the seed of the Carolina clover is hard, so that if a quick stand is wanted a rather heavy seeding must be made. No experiments have been made with these plants, but in view of the small size of the seed it seems as though five pounds per acre of the hop clovers and eight pounds of Carolina clover should be enough. To insure even distribution it is well to mix the seed with sifted loam or sand. Humus-Producing Materials and the Making and Use of Compost By R. A. Oakley and H. L. 'Vest oyer Organic matter, or humus, as a constituent of soil, bears a very important relation to the growth of plants. This is a fact that was discovered by man early in his agricultural efforts. Just as he had a knowledge of the plants that were worth his while to grow, it is reasonable to suppose he early learned the difference between poor and productive soils, and what common substances he could add to them to increase their productivity. -
Dynamics of Carbon 14 in Soils: a Review C
Radioprotection, Suppl. 1, vol. 40 (2005) S465-S470 © EDP Sciences, 2005 DOI: 10.1051/radiopro:2005s1-068 Dynamics of Carbon 14 in soils: A review C. Tamponnet Institute of Radioprotection and Nuclear Safety, DEI/SECRE, CADARACHE, BP. 1, 13108 Saint-Paul-lez-Durance Cedex, France, e-mail: [email protected] Abstract. In terrestrial ecosystems, soil is the main interface between atmosphere, hydrosphere, lithosphere and biosphere. Its interactions with carbon cycle are primordial. Information about carbon 14 dynamics in soils is quite dispersed and an up-to-date status is therefore presented in this paper. Carbon 14 dynamics in soils are governed by physical processes (soil structure, soil aggregation, soil erosion) chemical processes (sequestration by soil components either mineral or organic), and soil biological processes (soil microbes, soil fauna, soil biochemistry). The relative importance of such processes varied remarkably among the various biomes (tropical forest, temperate forest, boreal forest, tropical savannah, temperate pastures, deserts, tundra, marshlands, agro ecosystems) encountered in the terrestrial ecosphere. Moreover, application for a simplified modelling of carbon 14 dynamics in soils is proposed. 1. INTRODUCTION The importance of carbon 14 of anthropic origin in the environment has been quite early a matter of concern for the authorities [1]. When the behaviour of carbon 14 in the environment is to be modelled, it is an absolute necessity to understand the biogeochemical cycles of carbon. One can distinguish indeed, a global cycle of carbon from different local cycles. As far as the biosphere is concerned, pedosphere is considered as a primordial exchange zone. Pedosphere, which will be named from now on as soils, is mainly located at the interface between atmosphere and lithosphere. -
World Reference Base for Soil Resources 2014 International Soil Classification System for Naming Soils and Creating Legends for Soil Maps
ISSN 0532-0488 WORLD SOIL RESOURCES REPORTS 106 World reference base for soil resources 2014 International soil classification system for naming soils and creating legends for soil maps Update 2015 Cover photographs (left to right): Ekranic Technosol – Austria (©Erika Michéli) Reductaquic Cryosol – Russia (©Maria Gerasimova) Ferralic Nitisol – Australia (©Ben Harms) Pellic Vertisol – Bulgaria (©Erika Michéli) Albic Podzol – Czech Republic (©Erika Michéli) Hypercalcic Kastanozem – Mexico (©Carlos Cruz Gaistardo) Stagnic Luvisol – South Africa (©Márta Fuchs) Copies of FAO publications can be requested from: SALES AND MARKETING GROUP Information Division Food and Agriculture Organization of the United Nations Viale delle Terme di Caracalla 00100 Rome, Italy E-mail: [email protected] Fax: (+39) 06 57053360 Web site: http://www.fao.org WORLD SOIL World reference base RESOURCES REPORTS for soil resources 2014 106 International soil classification system for naming soils and creating legends for soil maps Update 2015 FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS Rome, 2015 The designations employed and the presentation of material in this information product do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations (FAO) concerning the legal or development status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. The mention of specific companies or products of manufacturers, whether or not these have been patented, does not imply that these have been endorsed or recommended by FAO in preference to others of a similar nature that are not mentioned. The views expressed in this information product are those of the author(s) and do not necessarily reflect the views or policies of FAO. -
The Nature and Dynamics of Soil Organic Matter: Plant Inputs, Microbial Transformations, and Organic Matter Stabilization
Soil Biology & Biochemistry 98 (2016) 109e126 Contents lists available at ScienceDirect Soil Biology & Biochemistry journal homepage: www.elsevier.com/locate/soilbio Review paper The nature and dynamics of soil organic matter: Plant inputs, microbial transformations, and organic matter stabilization Eldor A. Paul Natural Resource Ecology Laboratory and Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO 80523-1499, USA article info abstract Article history: This review covers historical perspectives, the role of plant inputs, and the nature and dynamics of soil Received 19 November 2015 organic matter (SOM), often known as humus. Information on turnover of organic matter components, Received in revised form the role of microbial products, and modeling of SOM, and tracer research should help us to anticipate 31 March 2016 what future research may answer today's challenges. Our globe's most important natural resource is best Accepted 1 April 2016 studied relative to its chemistry, dynamics, matrix interactions, and microbial transformations. Humus has similar, worldwide characteristics, but varies with abiotic controls, soil type, vegetation inputs and composition, and the soil biota. It contains carbohydrates, proteins, lipids, phenol-aromatics, protein- Keywords: Soil organic matter derived and cyclic nitrogenous compounds, and some still unknown compounds. Protection of trans- 13C formed plant residues and microbial products occurs through spatial inaccessibility-resource availability, 14C aggregation of mineral and organic constituents, and interactions with sesquioxides, cations, silts, and Plant residue decomposition clays. Tracers that became available in the mid-20th century made the study of SOM dynamics possible. Soil carbon dynamics Carbon dating identified resistant, often mineral-associated, materials to be thousands of years old, 13 Humus especially at depth in the profile. -
Soil Stratification Using the Dual- Pore-Pressure Piezocone Test
68 TRANSPORTATION RESEARCH RECORD 1235 Soil Stratification Using the Dual Pore-Pressure Piezocone Test ILAN JURAN AND MEHMET T. TUMAY Among in situ testing techniques presently used in soil stratification urated soil to dilate or contract during shearing. The pore and identification, the electric quasistatic cone penetration test water pressures measured at the cone tip and the shaft imme (QCPT) is recognized as a reliable, simple, fast, and economical diately behind the cone tip were found to be highly dependent test. Installation of pressure transducers inside cone penetrometers upon the stress history, sensitivity, and stiffness-to-strength to measure pore pressures generated during a sounding has added ratio of the soil. Therefore, several charts dealing with soil a new dimension to QCPT-the piezocone penetration test (PCPT). classification and stress history [i.e., overconsolidation ratio In this paper, some of the major design, testing, de-airing, and interpretive problems with regard to a new piezocone penetro· (OCR)] have been developed using the point resistance and meter with dual pore pressure measurement (DPCPT) are addressed. the excess pore water pressures measured immediare/y behind Results of field investigations indicate that DPCPT provides an the tip (18-20) and at the cone tip (6,16), respectively. enhanced capability of identifying and classirying minute loose or Interpretation of excess pore water pressures (ilu = u, - dense sand inclusions in low-permeability clay deposits. u0 , where u0 is hydrostatic water pressure) measured in sandy soils, and their use in soil classification, are more complex The construction of highway embankments and reclamation because the magnitude of these pore water pressures is highly projects in deltaic zones often requires continuous soil pro dependent upon the ratio of the penetration rate to hydraulic filing to establish the stratification of heterogeneous soil conductivity of the soil.