Soil life or soil biota is a collective term for all the organisms living within the soil.

Overview

In a balanced soil, plants grow in an active and vibrant environment. The mineral content of the soil and its physical structure are important for their well-being, but it is the life in the earth that powers its cycles and provides its fertility. Without the activities of soil organisms, organic materials would accumulate and litter the soil surface, and there would be no food for florcitas. The soil biota includes: A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition, a highly ordered atomic structure and specific physical properties. ... Organic material or organic matter is informally used to denote a material that originated as a living organism; most such materials contain carbon and are capable of decay. ...

• Megafauna: size range 20 mm upwards, e.g. moles, rabbits, and rodents.
• Macrofauna: size range 2-20 mm, e.g. woodlice, arañas, earthworms, beetles, centipedes, slugs, snails, ants, and harvestmen.
• Mesofauna: size range 100 micrometre-2 mm, e.g. tardigrades, mites and springtails.
• Microfauna and Microflora: size range 1-100 micrometres, e.g. yeasts, bacteria, fungi, protozoa, roundworms, and rotifers.

Of these, bacteria and fungi play key roles in maintaining a healthy soil. They act as decomposers that break down organic materials to produce detritus and other breakdown products. Soil detritivores, like earthworms, ingest detritus and decompose it. Saprotrophs, well represented by fungi and bacteria, extract soiluble nutrients from delitro. I rule woot. Pineapple and cheese marshmellows now on sale at piggly wiggly. For other uses, see Mole. ... Genera Pentalagus Bunolagus Nesolagus Romerolagus Brachylagus Sylvilagus Oryctolagus Poelagus Rabbits are small mammals in the family Leporidae of the order Lagomorpha, found in several parts of the world. ... Suborders Sciuromorpha Castorimorpha Myomorpha Anomaluromorpha Hystricomorpha Rodentia is an order of mammals also known as rodents. ... Infraorders and Families Infraorder Tylomorpha Tylidae Infraorder Ligiamorpha Superfamily Trichoniscoidea Buddelundiellidae Trichoniscidae Superfamily Styloniscoidea Schoebliidae Styloniscidae Titaniidae Tunanoniscidae Superfamily Oniscoidea Bathytropidae Berytoniscidae Detonidae Halophilosciidae Olibrinidae Oniscidae Philosciidae Platyarthridae Pudeoniscidae Rhyscotidae Scyphacidae Speleoniscidae Sphaeroniscidae Stenoniscidae Tendosphaeridae Superfamily Armadilloidea Actaeciidae Armadillidae Armadillidiidae Atlantidiidae Balloniscidae Cylisticidae Eubelidae Periscyphicidae Porcellionidae Trachelipodidae incertae sedis (Ligiamorpha... Araña (Anya Sofia Corazon) is a fictional character from the Marvel Universe. ... Families   Acanthodrilidae   Ailoscolecidae   Alluroididae   Almidae   Criodrilidae   Eudrilidae   Exxidae   Glossoscolecidae   Lumbricidae   Lutodrilidae   Megascolecidae   Microchaetidae   Ocnerodrilidae   Octochaetidae   Sparganophilidae Earthworm is the common name for the largest members of the Oligochaeta (which is either a class or subclass depending on the author) in the phylum Annelida. ... Suborders Adephaga Archostemata Myxophaga Polyphaga See subgroups of the order Coleoptera Beetles are the most diverse group of insects. ... For other uses, see Centipede (disambiguation). ... This article is about Terrestrial Slugs. ... This article is about the animal. ... For other uses, see Ant (disambiguation). ... The Phalangids or Opiliones (better known as harvestmen or daddy longlegs) are eight-legged invertebrate animals belonging to the order Opiliones in the class Arachnida, in the subphylum Chelicerata of the phylum Arthropoda. ... A micrometre (American spelling: micrometer, symbol µm) is an SI unit of length equal to one millionth of a metre, or about a tenth of the diameter of a droplet of mist or fog. ... Classes [2] Heterotardigrada Mesotardigrada Eutardigrada Tardigrades or water bears comprise the phylum Tardigrada. ... Look up mite in Wiktionary, the free dictionary. ... Families [1] Suborder Arthropleona Superfamily Entomobryoidea Entomobryidae Isotomidae Oncopoduridae Paronellidae Tomoceridae Superfamily Poduroidea Brachystomellidae Hypogastruridae Neanuridae Odontellidae Onychiuridae Poduridae Suborder Symphypleona Dicyrtomidae Katiannidae Sminthuridae Sminthurididae Bourletiellidae Arrhopalitidae Springtails (Order Collembola) form the largest of the three orders of modern hexapods that are no longer considered to be insects (along with... Typical divisions Ascomycota (sac fungi) Saccharomycotina (true yeasts) Taphrinomycotina Schizosaccharomycetes (fission yeasts) Basidiomycota (club fungi) Urediniomycetes Sporidiales Yeasts are a growth form of eukaryotic microorganisms classified in the kingdom Fungi, with approximately 1,500 species described. ... Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ... Subkingdom/Phyla Chytridiomycota Blastocladiomycota Neocallimastigomycota Glomeromycota Zygomycota Dikarya (inc. ... Wikisource has an original article from the 1911 Encyclopædia Britannica about: Protozoa Protozoa (in Greek proto = first and zoa = animals) are single-celled eukaryotes (organisms whose cells have nuclei) that commonly show characteristics usually associated with animals, most notably mobility and heterotrophy. ... Classes Adenophorea    Subclass Enoplia    Subclass Chromadoria Secernentea    Subclass Rhabditia    Subclass Spiruria    Subclass Diplogasteria The roundworms or nematodes (Phylum Nematoda from Gr. ... Classes Monogononta Digononta The rotifers make up a phylum of microscopic and near-microscopic pseudocoelomate animals. ... Decomposers (also called reducers) are organisms (often fungi or bacteria) that break down organic materials to gain nutrients and energy. ... In biology, detritus is organic waste material from decomposing dead plants or animals. ... A dung beetle rolling a ball of dung Detritivores (also known as saprophages, detrivores or detritus feeders) are organisms that recycle detritus (decomposing organic material), returning it into the food chain. ... A Saprotroph (or saprobe) is an organism that obtains its nutrients from non-living organic matter, usually dead and decaying plant or animal matter, by absorbing soluble organic compounds. ...

Bacteria

Bacteria are single-celled organisms, and are the most numerous denizens of the soil, with populations ranging from 100 million to 3 billion in a gram. They are capable of very rapid reproduction by binary fission (dividing into two) in favourable conditions. One bacterium is capable of producing 16 million more in just 24 hours. Most soil bacteria live in close proximity to plant roots and are often referred to as rhizobacteria. Bacteria live in soil water, including the film of moisture surrounding soil particles, and some are able to swim by means of flagella. The majority of the beneficial soil-dwelling bacteria need oxygen (and are thus termed aerobic bacteria), whilst those that do not require air are referred to as anaerobic, and tend to cause putrefaction of dead organic matter. Aerobic bacteria are most active in a soil that is moist (but not saturated, as this will deprive aerobic bacteria of the air that they require), and neutral soil pH, and where there is plenty of food (carbohydrates and micronutrients from organic matter) available. Hostile conditions will not completely kill bacteria; rather, the bacteria will stop growing and get into a dormant stage, or may mutate to adapt to the new conditions. Gram positive bacteria produce spores in order to wait for more favourable circumstances, and Gram negative bacteria gets into a "nonculturable" stage. Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ... // A flagellum (plural: flagella) is a long, slender projection from the cell body, composed of microtubules and surrounded by the plasma membrane. ... Aerobic and anaerobic bacteria can be identified by growning them in liquid culture: 1: Obligate aerobic bacteria gather at the top of the test tube in order to absorb maximal amount of oxygen. ... Aerobic and anaerobic bacteria can be identified by growning them in liquid culture: 1: Obligate aerobic bacteria gather at the top of the test tube in order to absorb maximal amount of oxygen. ... Putrefaction is the decomposition of proteins, especially by anaerobic microorganisms. ... Loess field in Germany Surface-water-gley developed in glacial till, Northern Ireland Technically, soil forms the pedosphere: the interface between the lithosphere (rocky part of the planet) and the biosphere, atmosphere, and hydrosphere. ... This does not cite any references or sources. ... Lactose is a disaccharide found in milk. ... Micronutrients for plants: There are about eight nutrients essential to plant growth and health that are only present in very small quantities. ... It has been suggested that mutant be merged into this article or section. ...

From the organic gardener's point of view, the important roles that bacteria play are:

The nitrogen cycle

This is an image of nitrogen cycle taken from this [1] EPA website. ... This is an image of nitrogen cycle taken from this [1] EPA website. ...

Nitrification

Nitrification is a vital part of the nitrogen cycle wherein certain bacteria (which manufacture their own carbohydrate supply without using the process of photosynthesis) are able to transform nitrogen in the form of ammonium, which is produced by the decomposition of proteins, into nitrates, which are available to growing plants, and once again converted to proteins. Nitrogen cycle Nitrification is the biological oxidation of ammonia with oxygen into nitrite followed by the oxidation of these nitrites into nitrates. ... Schematic representation of the flow of Nitrogen through the environment. ... Lactose is a disaccharide found in milk. ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ...

Nitrogen fixation

In another part of the cycle, the process of nitrogen fixation constantly puts additional nitrogen into biological circulation. This is carried out by free-living nitrogen-fixing bacteria in the soil or water such as Azotobacter, or by those which live in close symbiosis with leguminous plants, such as rhizobia. These bacteria form colonies in nodules they create on the roots of peas, beans, and related species. These are able to convert nitrogen from the atmosphere into nitrogen-containing organic substances. Nitrogen fixation is the process by which nitrogen is taken from its relatively inert molecular form (N2) in the atmosphere and converted into nitrogen compounds (such as, notably, ammonia, nitrate and nitrogen dioxide)[1] useful for other chemical processes. ... Species A. vinladii Azotobacter are usually motile, oval, or spherical bacteria, form thick-walled cysts, and may produce large quantities of capsular slime. ... Varieties of soybean seeds, a popular legume Pea pods A legume is a plant in the family Fabaceae (or Leguminosae), or a fruit of these plants. ... Soybean root nodules, each containing billions of Bradyrhizobium bacteria Rhizobia (from the Greek words riza = root and bios = Life) are soil bacteria that fix nitrogen (diazotrophy) after becoming established inside root nodules of legumes (Fabaceae). ... Binomial name L. Percentages are relative to US recommendations for adults. ... For other uses, see Bean (disambiguation). ...

Denitrification

While nitrogen fixation converts nitrogen from the atmosphere into organic compounds, a series of processes called denitrification returns an approximately equal amount of nitrogen to the atmosphere. Denitrifying bacteria tend to be anaerobes, or facultatively anaerobes (can alter between the oxygen dependent and oxygen independent types of metabolisms), including Achromobacter and Pseudomonas. The putrefaction process caused by oxygen-free conditions converts nitrates and nitrites in soil into nitrogen gas or into gaseous compounds such as nitrous oxide or nitric oxide. In excess, denitrification can lead to overall losses of available soil nitrogen and subsequent loss of soil fertility. However, fixed nitrogen may circulate many times between organisms and the soil before denitrification returns it to the atmosphere. The diagram below illustrates the nitrogen cycle. “Air” redirects here. ... Type species Achromobacter xylosoxidans Species A. ruhlandii The Achromobacter are a genus of bacteria, included in the order Burkholderiales. ... Type species Pseudomonas aeruginosa Species group P. aeruginosa P. alcaligenes P. anguilliseptica P. argentinensis P. borbori P. citronellolis P. flavescens P. mendocina P. nitroreducens P. oleovorans P. pseudoalcaligenes P. resinovorans P. straminea group P. aurantiaca P. aureofaciens P. chlororaphis P. fragi P. lundensis P. taetrolens group P. antarctica P. azotoformans... For other uses, see Nitrous oxide (disambiguation). ... R-phrases , , , , S-phrases , , , Supplementary data page Structure and properties n, εr, etc. ...

Actinobacteria

Actinobacteria are critical in the decomposition of organic matter and in humus formation, and their presence is responsible for the sweet "earthy" aroma which is associated with a good healthy soil. They require plenty of air and a pH between 6.0 and 7.5, but are more tolerant of dry conditions than most other bacteria and fungi. Subclasses Acidimicrobidae Actinobacteridae Coriobacteridae Rubrobacteridae Sphaerobacteridae The Actinobacteria or Actinomycetes are a group of Gram-positive bacteria. ... This article does not cite any references or sources. ... This article does not cite any references or sources. ...

Fungi

A gram of garden soil can contain around one million fungi, such as yeasts and moulds. Fungi have no chlorophyll, and are not able to photosynthesise; besides, they can't use atmospheric carbon dioxide as a source of carbon, therefore they are chemo-heterotrophic, meaning that, like animals, they require a chemical source of energy rather than being able to use light as an energy source, as well as organic substrates to get carbon for growth and development. Subkingdom/Phyla Chytridiomycota Blastocladiomycota Neocallimastigomycota Glomeromycota Zygomycota Dikarya (inc. ... Typical divisions Ascomycota (sac fungi) Saccharomycotina (true yeasts) Taphrinomycotina Schizosaccharomycetes (fission yeasts) Basidiomycota (club fungi) Urediniomycetes Sporidiales Yeasts are a growth form of eukaryotic microorganisms classified in the kingdom Fungi, with approximately 1,500 species described. ... Moldy cream cheese Molds (British English: moulds) are various fungi that cover surfaces as fluffy mycelium and usually produce masses of asexual, sometimes sexual spores. ... Chlorophyll gives leaves their green color Space-filling model of the chlorophyll molecule Chlorophyll is a green pigment found in most plants, algae, and cyanobacteria. ... The leaf is the primary site of photosynthesis in plants. ... A chemoorganoheterotrophic organism is one that requires organic substrates to get its energy from oxido-reduction of an organic compound. ... For other uses, see Animal (disambiguation). ...

Many fungi are parasitic, often causing disease to their living host plant, although some have beneficial relationships with living plants as we shall see below. In terms of soil and humus creation, the most important fungi tend to be saprotrophic, that is, they live on dead or decaying organic matter, thus breaking it down and converting it to forms which are available to the higher plants. A succession of fungi species will colonise the dead matter, beginning with those that use sugars and starches, which are succeeded by those that are able to break down cellulose and lignins. A saprotroph (or saprobe) is an organism that obtains its nutrients from non-living organic matter, usually dead and decaying plant or animal matter, by absorbing soluble organic compounds. ... Cellulose as polymer of β-D-glucose Cellulose in 3D Cellulose (C6H10O5)n is a polysaccharide of beta-glucose. ... Lignin (sometimes lignen) is a chemical compound (complex, highly cross-linked aromatic polymer) that is most commonly derived from wood and is an integral part of the cell walls of plants, especially in tracheids, xylem fibres and sclereids. ...

Fungi spread underground by sending long thin threads known as mycelium throughout the soil; these threads can be observed throughout many soils and compost heaps. From the mycelia the fungi is able to throw up its fruiting bodies, the visible part above the soil (e.g., mushrooms, toadstools and puffballs) which may contain millions of spores. When the fruiting body bursts, these spores are dispersed through the air to settle in fresh environments, and are able to lie dormant for up to years until the right conditions for their activation arise or the right food is made available. Mycelium is the vegetative part of a fungus, consisting of a mass of branching, thread-like hyphae. ... A handful of compost Compost is the aerobically decomposed remnants of organic materials (those with plant and animal origins). ... For other uses, see Mushroom (disambiguation). ... Basidiocarps (mushrooms) of the fungus Leucocoprinus sp. ... An agaricoid puffball, Podaxis pistillaris, the False Shaggy Mane Puffball emitting spores A puffball is a member of any of a number of groups of fungus in the division Basidiomycota. ... This article or section is in need of attention from an expert on the subject. ... Mushroom In fungi, the fruiting body (also known as sporocarp) is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne. ...

Mycorrhizae

Those fungi that are able to live symbiotically with living plants, creating a relationship that is beneficial to both, are known as Mycorrhizae (from myco meaning fungal and rhiza meaning root). Plant root hairs are invaded by the mycelia of the mycorrhiza, which lives partly in the soil and partly in the root, and may either cover the length of the root hair as a sheath or be concentrated around its tip. The mycorrhiza obtains the carbohydrates that it requires from the root, in return providing the plant with nutrients including nitrogen and moisture. Later the plant roots will also absorb the mycelium into its own tissues. A mycorrhiza (typically seen in the plural forms mycorrhizae or mycorrhizas, Greek for fungus roots) is the result of a mutualistic association between a fungus and a plant. ...

Beneficial mycorrhizal associations are to be found in many of our edible and flowering crops. Shewell Cooper suggests that these include at least 80% of the brassica and solanum families (including tomatoes and potatoes), as well as the majority of tree species, especially in forest and woodlands. Here the mycorrhizae create a fine underground mesh which extends greatly beyond the limits of the tree's roots, thus greatly increasing their feeding range and actually causing neighbouring trees to become physically interconnected. The benefits of mycorrhizal relations to their plant partners are not limited to nutrients, but can be essential for plant reproduction: in situations where little light is able to reach the forest floor, such as the North American pine forests, a young seedling cannot obtain sufficient light to photosynthesise for itself and will not grow properly in a sterile soil. But if the ground is underlain by a mycorrhizal mat then the developing seedling will throw down roots that can link with the fungal threads and through them obtain the nutrients it needs, often indirectly obtained from its parents or neighbouring trees. Dr. Shewell Cooper- organic gardener and pioneer of no dig cultivation systems, author of Soil, Humus and Health and founder of the Good Gardeners Association. ... Species See text. ... Species See text. ... For other uses, see Tomato (disambiguation). ... For other uses, see Potato (disambiguation). ... The coniferous Coast Redwood, the tallest tree species on earth. ... This article is about a community of trees. ... This article deals with the tree; for the e-mail client see Pine email client Species About 115. ...

David Attenborough points out the plant/fungi/animal relationship that creates a "Three way harmonious trio" to be found in forest ecosystems wherein the plant/fungi symbiosis is enhanced by animals such as the wild boar, deer, mice or flying squirrel which feed upon the fungi's fruiting bodies, including truffles, and cause their further spread (Private Life Of Plants, 1995). Beginning to understand the delicate and complex relationships which pervade natural systems is yet another reason why the sensitive organic gardener will refrain from the use of artificial fertilisers and herbicides/fungicides which may irreparably damage such balances. Sir David Frederick Attenborough, OM, CH, CVO, CBE, FRS (born on May 8, 1926 in London, England) is one of the worlds best known broadcasters and naturalists. ... A coral reef near the Hawaiian islands is an example of a complex marine ecosystem. ... It has been suggested that this article or section be merged with Organic horticulture. ...

See also

• Agroecology
• Biogeochemical cycle
• Soil biology
• Soil zoology
• Soil food web

Agroecology is the science of applying ecological concepts and principles to the design, development, and management of sustainable agricultural systems. ... In ecology, a biogeochemical cycle is a circuit where a nutrient moves back and forth between both biotic and abiotic components of ecosystems. ... Soil biology is the study of microbial and faunal activity and ecology in soil. ... Soil zoology is the study of animals living fully or partially in the soil (soil fauna). ... Soil Food Web The Soil food web describes a complex living system in the soil and how it interacts with the environment, plants, and animals. ...

External links

• The real dirt on no-till soil (pdf file)
• Why organic fertilizers are a good choice for healthy soil
• Effects of transgenic zeaxanthin potatoes on soil life and soil quality Biosafety research project