DOCSLIB.ORG

The Soil Food Web Tuning in to the World Beneath Our Feet

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Soil Food Web Tuning in to the World Beneath Our Feet The Soil Food Web Tuning in to the World Beneath Our Feet by Mary-Howell R. Martens Elaine Ingham, Ph.D., has been at nseen beneath our feet, there dwells the forefront of Ua teeming microscopic universe of educating farmers complex living organisms that few humans about the value of ever consider. In one teaspoon of soil alone, understanding there may be over 600 million bacterial soil life. cells, and if that soil comes from the im- mediate root zone of a healthy plant, the number can exceed a million bacteria of many different species. These bacterial cells exist in complex predator-prey relation- ships with countless other diverse organ- isms. This topsoil food web forms the foun- dation for healthy soil, for healthy plants, and ultimately for a healthy planet. It is an essential but exceedingly delicate founda- The exchange of minerals and nutrients between plants tion that even the brightest scientists know and fungi represent a critical link to plant health and very little about. productivity. Above, ectomycorrhzial fungi, commonly Dr. Elaine Ingham has been research- associated with trees and grapes, form a protective ing this tiny universe for nearly 20 years. sheath around plant roots, making soil nutrients She has sought to understand the impor- available to the root cells and protecting the plant from tance of these organisms and the relation- pathogenic attack. ships that exist between them, and to elu- cidate the effects that various agricultural Again she found great differences in spe- web? This is not a simple question. The practices have on this vast network of life. cies present and numbers of the typical or- food web has a basic set of expected or- For part of her Ph.D. dissertation in 1981 ganisms in response to other important fac- ganism groups, but the numbers of organ- at Colorado State University, Dr. Ingham tors in the soil. isms and different species in each group researched the soil food web structures in Over the course of Ingham’s education can vary significantly by soil type, climate, Colorado soils that were farmed with and and subsequent career as a professor at plants present and management. Plants and without irrigation. She compared these re- Oregon State University and most recently plant structures are a major component in sults to native grassland soils. Not surpris- with Soil Foodweb Inc., a research and determining the food resources in soil that ingly, she discovered that the introduction consulting firm in Corvallis, Oregon, she will be available to bacteria and fungi. Pho- of agricultural systems altered the species has developed methods to quantify and tosynthesizing living plant material pro- of organisms present, particularly the fun- identify the microbial populations of soils. vides the initial energy to the soil food sys- gi, which are easily destroyed by agricul- She has learned that most traditional tech- tem through their roots. Living plant roots tural pesticides. For her postdoctoral work, niques of petri plate counts grossly under- exude many types of complex high-energy she compared grassland soils to high moun- estimate both number and diversity of spe- nutrient molecules into the surrounding tain meadow and pine forest soils, work- cies present in soil, since the artificial soil. Dead plant material is decomposed by ing across a typical successional gradient. conditions are not suitable for the growth bacteria and fungi, building up even great- of 99.99 percent of bacte- er numbers of these or- Reprinted from “It is important to view the rial species and of most ganisms and their meta- other organisms. To cir- bolic products. The more soil food web as a complex, cumvent this problem, In- diverse the initial plant whole system. When any group gham has developed effec- population, the greater the tive alternative techniques April 2000 - Vol. 30, No. 4 - Cover Story diversity of plant products of organisms in the system is based on direct enumera- that will be released, eliminated or damaged, the tion methods. She uses this information to thereby sustaining an increased variety of assist farmers and researchers by offering microbial organisms. delicate balance of a service that assesses the health and pro- For a healthy soil, unaltered by the appli- interrelationships can ductivity of their soil by measuring the di- cation of lethal agricultural chemicals, these versity and vitality of the soil food web. “microherds” of microbes colonize the root be shifted.” Which organisms compose this soil food zone, the rhizosphere, of the plant. Most are 75 have been studied to determine their ef- fects on soil organisms. The remaining in- gredients have never been studied for their effects on the whole system or on any non- target group. Scientists don’t fully under- stand the effect of any individual ingredi- ent on soil life, much less the synergistic effects of the ingredients, or combination- al effects with inert or soil materials. It is hardly surprising that a soil treated with numerous agricultural chemicals lacks a healthy food web. Plants growing in un- healthy soil require additional fertilizers and pesticides, furthering the deadly spiral. As a plant grows, photosynthesis sup- plies much more than the individual plant’s carbohydrate requirements. It has been documented that plant roots can exude over 50 percent of the carbon fixed through pho- tosynthesis in the form of simple sugars, proteins, amino acids, vitamins, and other complex carbohydrates. The types of mol- ecules released are specific for a variety of plants grown under certain conditions, forming in effect a unique chemical signa- The soil food web is the community of organisms living all or part of their lives in the ture. As these molecules are released into soil. A food web diagram shows a series of conversions (represented by arrows) of the rhizosphere, they serve as food and energy and nutrients as one organism eats another. growth stimulants for a certain mix of mi- crobes. Dr. Joyce Loper, of the USDA Ag- beneficial bacteria and fungi; they do not interrelationships can be shifted. Soil ecol- ricultural Research Service, and other sci- damage living plant tissue and are critical to ogists are just beginning to understand how entists have shown that for each plant making essential minerals available to the plant production can be affected when this species, this characteristic chemical soup plant. These microbes retain large amounts balance is altered. Many species of benefi- stimulates the development of a select, ben- of nitrogen, phosphorous, potassium, sulfur, cial bacteria and fungi die as food supplies eficial company of root-dwelling microbes. calcium, iron and many micronutrients in dwindle. Reduction in natural predators and This microbial population colonizes the their bodies, preventing these nutrients from decreased competition for certain food sup- root zone, producing certain chemicals that being leached or removed by water runoff. plies may allow other species to grow ram- inhibit the growth of pathogenic species. Ideally, they out-compete pathogenic species pantly. Plant nutrient availability often can These organisms also are instrumental in and form a protective layer on the surface of decline, and populations of pathogens can supplying the plant’s unique nutritional living plant roots. It is usually only when the rise. Much research is currently being done needs. beneficial species of bacteria and fungi are on this subject, attempting to comprehend The residual effects of this unique mi- killed by continuous soil disturbance and tox- how such changes occur. crobial population in subsequent years may ic chemicals that pathogenic species have an also help explain why certain crop rotations advantage. HERBICIDES, PESTICIDES work better than others. It is possible that As in more familiar aboveground eco- & FERTILIZERS the microbial population nurtured by one systems, there are other organisms present As part of her research, Dr. Ingham has crop species creates a nutritional or micro- that prey on these herbivores. The preda- shown that herbicides, pesticides and fer- bial environment that is well suited to a par- tors are primarily beneficial nematodes, tilizers have many non- ticular subsequent crop predatory nematodes, protozoa, mites and target effects. The most Reprinted from species but not perhaps other tiny animals which serve to recycle common pesticides are for others. For example, it nutrients in the system and to keep other fairly broad spectrum; that is likely that crops like populations in balance. These predators, in is, they kill much more broccoli, which inhibit the turn, are eaten by other animals, primarily than the target species. April 2000 - Vol. 30, No. 4 - Cover Story growth of mycorrhizal those that spend some portion of their life Residual pesticides that fungi, reduce the produc- aboveground, such as insects, birds and accumulate in soil over many years may tivity of a following crop such as corn, small animals. recombine and form new, unintentional which requires mycorrhizal fungi. While It is important to view the soil food web chemicals that have additional and often this has not been conclusively proven, it as a complex, whole system. When any synergistic negative effects. Out of the 650 could form part of the basis for a better un- group of organisms in the system is elimi- active ingredients used to formulate most derstanding of observable crop rotational nated or damaged, the delicate balance of common agricultural pesticides, only about effects. Certain soil amendments favor the system of nitrogen cycling that has development of a diverse microbial pop- worked brilliantly for the past million ulation. Compost in particular can im- years. prove soil nutritional availability and Compare this system to another famil- soil tilth because of its complex micro- iar situation; when inorganic ammonium bial population. Composts bring with nitrate fertilizer is applied to agricultural them a wide array of bacteria, fungi, pro- soil, ammonium and nitrate ions are rap- tozoa, nematodes and microarthropods, idly released into the soil solution.
Load more

Recommended publications
  • 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.
    [Show full text]
  • The Soil Survey
    The Soil Survey The soil survey delineates the basal soil pattern of an area and characterises each kind of soil so that the response to changes can be assessed and used as a basis for prediction. Although in an economic climate it is necessarily made for some practical purpose, it is not subordinated to the parti­ cular need of the moment, but is conducted in a scientific way that provides basal information of general application and eliminates the necessity for a resurvey whenever a new problem arises. It supplies information that can be combined, analysed, or amplified for many practical purposes, but the purpose should not be allowed to modify the method of survey in any fundamental way. According to the degree of detail required, soil surveys in New Zealand are classed as general, . district, or detailed. General surveys produce sufficient detail for a final map on the scale of 4 miles to an inch (1 :253440); they show the main sets of soils and their general relation to land forms; they are an aid to investigations and planning on the regional or national scale. District surveys, for maps, on the scale of 2 miles to an inch (1: 126720), show soil types or, where the pattern is detailed, combinations of types; they are designed to show the soil pattern in sufficient detail to allow the study of local soil problems and to provide a basis for assembling and distributing information in many fields such as agriculture, forestry, and engineering. Detailed surveys, mostiy for maps on the scale of 40 chains to an inch (1 :31680), delineate soil types and land-use phases, and show the soil pattern in relation to farm boundaries and subdivisional fences.
    [Show full text]
  • Soil Acidification the Unseen Threat to Soil Health and Productivity
    Soil Acidification The unseen threat to soil health and productivity www.ces.vic.gov.au February 2009 Fact Sheet No. 7 This fact sheet is one of a series, developed from material presented in Victoria’s first comprehensive State of the Environment Report. The Report is a major undertaking of the Commissioner for Environmental Sustainability and covers a broad range of environmental issues affecting the State. Its purpose is to improve community understanding of Victoria’s environment, and through the use of recommendations, to ensure its protection for present and future generations. The report was released in December 2008 and is available at www.ces.vic.gov.au Key findings Acidification is also linked to erosion, salinity, and loss of soil biodiversity. Bacteria, earthworms and other soil organisms are • The cost of lost productivity to Victoria due to soil generally sensitive to soil pH and tend to decline as soils become acidification is estimated at $470 million per year. more acidic. • Soil acidification is accelerated by some land management practices and the area of acid soil is increasing. Victoria has up to 8.6 million ha of acidic soils including • Naturally acidic soils can’t be distinguished from soils 4–5 million ha of strongly acidic soils, which mostly occur acidified by agriculture. naturally and are indistinguishable from those with accelerated • The use of acidifying fertiliser, to support more intensive acidification. agriculture, is increasing in Victoria. • Only 5.5% of the area requiring treatment with lime to restore Coastal acid sulfate soils are a different category of acid soils and critical soil pH levels is sufficiently treated.
    [Show full text]
  • Advanced Crop and Soil Science. a Blacksburg. Agricultural
    DOCUMENT RESUME ED 098 289 CB 002 33$ AUTHOR Miller, Larry E. TITLE What Is Soil? Advanced Crop and Soil Science. A Course of Study. INSTITUTION Virginia Polytechnic Inst. and State Univ., Blacksburg. Agricultural Education Program.; Virginia State Dept. of Education, Richmond. Agricultural Education Service. PUB DATE 74 NOTE 42p.; For related courses of study, see CE 002 333-337 and CE 003 222 EDRS PRICE MF-$0.75 HC-$1.85 PLUS POSTAGE DESCRIPTORS *Agricultural Education; *Agronomy; Behavioral Objectives; Conservation (Environment); Course Content; Course Descriptions; *Curriculum Guides; Ecological Factors; Environmental Education; *Instructional Materials; Lesson Plans; Natural Resources; Post Sc-tondary Education; Secondary Education; *Soil Science IDENTIFIERS Virginia ABSTRACT The course of study represents the first of six modules in advanced crop and soil science and introduces the griculture student to the topic of soil management. Upon completing the two day lesson, the student vill be able to define "soil", list the soil forming agencies, define and use soil terminology, and discuss soil formation and what makes up the soil complex. Information and directions necessary to make soil profiles are included for the instructor's use. The course outline suggests teaching procedures, behavioral objectives, teaching aids and references, problems, a summary, and evaluation. Following the lesson plans, pages are coded for use as handouts and overhead transparencies. A materials source list for the complete soil module is included. (MW) Agdex 506 BEST COPY AVAILABLE LJ US DEPARTMENT OFmrAITM E nufAT ION t WE 1. F ARE MAT IONAI. ItiST ifuf I OF EDuCATiCiN :),t; tnArh, t 1.t PI-1, t+ h 4t t wt 44t F.,.."11 4.
    [Show full text]
  • 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.
    [Show full text]
  • A Systemic Approach for Modeling Soil Functions
    SOIL, 4, 83–92, 2018 https://doi.org/10.5194/soil-4-83-2018 © Author(s) 2018. This work is distributed under SOIL the Creative Commons Attribution 4.0 License. A systemic approach for modeling soil functions Hans-Jörg Vogel1,5, Stephan Bartke1, Katrin Daedlow2, Katharina Helming2, Ingrid Kögel-Knabner3, Birgit Lang4, Eva Rabot1, David Russell4, Bastian Stößel1, Ulrich Weller1, Martin Wiesmeier3, and Ute Wollschläger1 1Helmholtz Centre for Environmental Research – UFZ, Permoserstr. 15, 04318 Leipzig, Germany 2Leibniz Centre for Agricultural Landscape Research (ZALF), Eberswalder Straße 84, 15374 Müncheberg, Germany 3TUM School of Life Sciences Weihenstephan, Technical University of Munich, Emil-Ramann-Straße 2, 85354 Freising, Germany 4Senckenberg Museum of Natural History, Sonnenplan 7, 02826 Görlitz, Germany 5Martin-Luther-University Halle-Wittenberg, Institute of Soil Science and Plant Nutrition, Von-Seckendorff-Platz 3, 06120 Halle (Saale), Germany Correspondence: Hans-Jörg Vogel ([email protected]) Received: 13 September 2017 – Discussion started: 4 October 2017 Revised: 2 February 2018 – Accepted: 14 February 2018 – Published: 15 March 2018 Abstract. The central importance of soil for the functioning of terrestrial systems is increasingly recognized. Critically relevant for water quality, climate control, nutrient cycling and biodiversity, soil provides more func- tions than just the basis for agricultural production. Nowadays, soil is increasingly under pressure as a limited resource for the production of food, energy and raw materials. This has led to an increasing demand for concepts assessing soil functions so that they can be adequately considered in decision-making aimed at sustainable soil management. The various soil science disciplines have progressively developed highly sophisticated methods to explore the multitude of physical, chemical and biological processes in soil.
    [Show full text]
  • A New Era of Digital Soil Mapping Across Forested Landscapes 14 Chuck Bulmera,*, David Pare´ B, Grant M
    CHAPTER A new era of digital soil mapping across forested landscapes 14 Chuck Bulmera,*, David Pare´ b, Grant M. Domkec aBC Ministry Forests Lands Natural Resource Operations Rural Development, Vernon, BC, Canada, bNatural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, Quebec, QC, Canada, cNorthern Research Station, USDA Forest Service, St. Paul, MN, United States *Corresponding author ABSTRACT Soil maps provide essential information for forest management, and a recent transformation of the map making process through digital soil mapping (DSM) is providing much improved soil information compared to what was available through traditional mapping methods. The improvements include higher resolution soil data for greater mapping extents, and incorporating a wide range of environmental factors to predict soil classes and attributes, along with a better understanding of mapping uncertainties. In this chapter, we provide a brief introduction to the concepts and methods underlying the digital soil map, outline the current state of DSM as it relates to forestry and global change, and provide some examples of how DSM can be applied to evaluate soil changes in response to multiple stressors. Throughout the chapter, we highlight the immense potential of DSM, but also describe some of the challenges that need to be overcome to truly realize this potential. Those challenges include finding ways to provide additional field data to train models and validate results, developing a group of highly skilled people with combined abilities in computational science and pedology, as well as the ongoing need to encourage communi- cation between the DSM community, land managers and decision makers whose work we believe can benefit from the new information provided by DSM.
    [Show full text]
  • Evaluation of Digital Soil Mapping Approaches with Large Sets of Environmental Covariates
    SOIL, 4, 1–22, 2018 https://doi.org/10.5194/soil-4-1-2018 © Author(s) 2018. This work is distributed under SOIL the Creative Commons Attribution 3.0 License. Evaluation of digital soil mapping approaches with large sets of environmental covariates Madlene Nussbaum1, Kay Spiess1, Andri Baltensweiler2, Urs Grob3, Armin Keller3, Lucie Greiner3, Michael E. Schaepman4, and Andreas Papritz1 1Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland 2Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, 8903 Birmensdorf, Switzerland 3Research Station Agroscope Reckenholz-Taenikon ART, Reckenholzstrasse 191, 8046 Zürich, Switzerland 4Remote Sensing Laboratories, University of Zurich, Wintherthurerstrasse 190, 8057 Zürich, Switzerland Correspondence: Madlene Nussbaum ([email protected]) Received: 19 April 2017 – Discussion started: 9 May 2017 Revised: 11 October 2017 – Accepted: 24 November 2017 – Published: 10 January 2018 Abstract. The spatial assessment of soil functions requires maps of basic soil properties. Unfortunately, these are either missing for many regions or are not available at the desired spatial resolution or down to the required soil depth. The field-based generation of large soil datasets and conventional soil maps remains costly. Mean- while, legacy soil data and comprehensive sets of spatial environmental data are available for many regions. Digital soil mapping (DSM) approaches relating soil data (responses) to environmental
    [Show full text]
  • Ecological Importance of Soil Bacterivores for Ecosystem Functions Jean Trap, Michael Bonkowski, Claude Plassard, Cécile Villenave, Eric Blanchart
    Ecological importance of soil bacterivores for ecosystem functions Jean Trap, Michael Bonkowski, Claude Plassard, Cécile Villenave, Eric Blanchart To cite this version: Jean Trap, Michael Bonkowski, Claude Plassard, Cécile Villenave, Eric Blanchart. Ecological impor- tance of soil bacterivores for ecosystem functions. Plant and Soil, Springer Verlag, 2015, 398 (1-2), pp.1-24. 10.1007/s11104-015-2671-6. hal-01214705 HAL Id: hal-01214705 https://hal.archives-ouvertes.fr/hal-01214705 Submitted on 12 Oct 2015 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Manuscript Click here to download Manuscript: manuscrit.doc Click here to view linked References 1 Number of words (main text): 8583 2 Number of words (abstract): 157 3 Number of figures: 7 4 Number of tables: 1 5 Number of appendix: 1 6 7 Title 8 Ecological importance of soil bacterivores on ecosystem functions 9 10 Authors 11 Jean Trap1, Michael Bonkowski2, Claude Plassard3, Cécile Villenave4, Eric Blanchart1 12 13 Affiliations 14 15 1Institut de Recherche pour le Développement – UMR Eco&Sols, 2 Place Viala, 34060, Version postprint 16 Montpellier, France 17 2Dept. of Terrestrial Ecology, Institut of Zoology, University of Cologne, D-50674 Köln, 18 Germany 19 3Institut National de Recherche Agronomique – UMR Eco&Sols, 2 Place Viala, 34060, 20 Montpellier, France 21 4ELISOL environnement, 10 avenue du Midi, 30111 Congenies, France 22 23 1 Comment citer ce document : Trap, J., Bonkowski, M., Plassard, C., Villenave, C., Blanchart, E.
    [Show full text]
  • The Soil Food Web
    THE SOIL FOOD WEB HEALTHY SOIL HEALTHY ENVIRONMENT The Soil Food Web Alan Sundermeier Extension Educator and Program Leader, Wood County Extension, The Ohio State University. Vinayak Shedekar Postdoctural Researcher, The Ohio State University. A healthy soil depends on the interaction of many organisms that make up the soil food web. These organisms live all or part of their life cycle in the soil and are respon- sible for converting energy as one organism consumes another. Source: Soil Biology Primer The phospholipid fatty acid (PLFA) test can be used to measure the activity of the soil food web. The following chart shows that mi-crobial activity peaks in early summer when soil is warm and moisture is adequate. Soil sampling for detecting soil microbes should follow this timetable to better capture soil microbe activity. The soil food web begins with the ener- gy from the sun, which triggers photo- synthesis in plants. Photosynthesis re- sults in plants using the sun’s energy to fix carbon dioxide from the atmosphere. This process creates the carbon and organic compounds contained in plant material. This is the first trophic level. Then begins building of soil organic matter, which contains both long-last- ing humus, and active organic matter. Active organic matter contains readily available energy, which can be used by simple soil organisms in the second trophic level of the soil food web. Source: Soil Biology Primer SOILHEALTH.OSU.EDU THE SOIL FOOD WEB - PAGE 2 The second trophic level contains simple soil organisms, which Agriculture can enhance the soil food web to create more decompose plant material.
    [Show full text]
  • Unit 2.3, Soil Biology and Ecology
    2.3 Soil Biology and Ecology Introduction 85 Lecture 1: Soil Biology and Ecology 87 Demonstration 1: Organic Matter Decomposition in Litter Bags Instructor’s Demonstration Outline 101 Step-by-Step Instructions for Students 103 Demonstration 2: Soil Respiration Instructor’s Demonstration Outline 105 Step-by-Step Instructions for Students 107 Demonstration 3: Assessing Earthworm Populations as Indicators of Soil Quality Instructor’s Demonstration Outline 111 Step-by-Step Instructions for Students 113 Demonstration 4: Soil Arthropods Instructor’s Demonstration Outline 115 Assessment Questions and Key 117 Resources 119 Appendices 1. Major Organic Components of Typical Decomposer 121 Food Sources 2. Litter Bag Data Sheet 122 3. Litter Bag Data Sheet Example 123 4. Soil Respiration Data Sheet 124 5. Earthworm Data Sheet 125 6. Arthropod Data Sheet 126 Part 2 – 84 | Unit 2.3 Soil Biology & Ecology Introduction: Soil Biology & Ecology UNIT OVERVIEW MODES OF INSTRUCTION This unit introduces students to the > LECTURE (1 LECTURE, 1.5 HOURS) biological properties and ecosystem The lecture covers the basic biology and ecosystem pro- processes of agricultural soils. cesses of soils, focusing on ways to improve soil quality for organic farming and gardening systems. The lecture reviews the constituents of soils > DEMONSTRATION 1: ORGANIC MATTER DECOMPOSITION and the physical characteristics and soil (1.5 HOURS) ecosystem processes that can be managed to In Demonstration 1, students will learn how to assess the improve soil quality. Demonstrations and capacity of different soils to decompose organic matter. exercises introduce students to techniques Discussion questions ask students to reflect on what envi- used to assess the biological properties of ronmental and management factors might have influenced soils.
    [Show full text]
  • Towards an Integrative Understanding of Soil Biodiversity
    Towards an integrative understanding of soil biodiversity Madhav Thakur, Helen Phillips, Ulrich Brose, Franciska de Vries, Patrick Lavelle, Michel Loreau, Jérôme Mathieu, Christian Mulder, Wim van der Putten, Matthias Rillig, et al. To cite this version: Madhav Thakur, Helen Phillips, Ulrich Brose, Franciska de Vries, Patrick Lavelle, et al.. Towards an integrative understanding of soil biodiversity. Biological Reviews, Wiley, 2020, 95, pp.350 - 364. 10.1111/brv.12567. hal-02499460 HAL Id: hal-02499460 https://hal.archives-ouvertes.fr/hal-02499460 Submitted on 5 Mar 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Biol. Rev. (2020), 95, pp. 350–364. 350 doi: 10.1111/brv.12567 Towards an integrative understanding of soil biodiversity Madhav P. Thakur1,2,3∗ , Helen R. P. Phillips2, Ulrich Brose2,4, Franciska T. De Vries5, Patrick Lavelle6, Michel Loreau7, Jerome Mathieu6, Christian Mulder8,WimH.Van der Putten1,9,MatthiasC.Rillig10,11, David A. Wardle12, Elizabeth M. Bach13, Marie L. C. Bartz14,15, Joanne M. Bennett2,16, Maria J. I. Briones17, George Brown18, Thibaud Decaens¨ 19, Nico Eisenhauer2,3, Olga Ferlian2,3, Carlos Antonio´ Guerra2,20, Birgitta Konig-Ries¨ 2,21, Alberto Orgiazzi22, Kelly S.
    [Show full text]