California Department of Resources Recycling and Recovery (CalRecycle)

Organic Materials Management


The following is a glossary of terms dealing with organic materials management in general. You may also be interested in the Conversion and Biomass to Energy Glossary.

Note: All terms in green link to a glossary definition on this page.

Term Explanation
Actinomycetes: Any of a group of generally low-oxygen–utilizing bacteria identified by a branching growth pattern that result in large threadlike structures. Many species occur in soil and are harmless to animals and higher plants.
Adjuvant: An ingredient that improves the properties of a formulation to which it has been added.
Aerate/aeration: To supply with air or expose to the circulation of air: aerate soil or soil aeration. Forced aeration refers to the use of blowers in a compost pile.
Aerobic: To be "with oxygen." Life or biological processes that can occur only in the presence of oxygen, such as the digestion of organic matter by bacteria.
Agricultural material: Material of plant or animal origin, which result from the production and processing of farm, ranch agricultural, horticultural, aquacultural, silvicultural, floricultural, vermicultural, or viticultural products, including manures, orchard and vineyard prunings, and crop residues.
Anaerobic: To be "without oxygen." A biological process occurring in the absence of oxygen, marked by a foul odor. These odors may include acetic acid, butyric acid, or putrescine.
(Greek--joint foot)
Any of numerous invertebrate animals of the phylum (family) Arthropoda, including the insects, crustaceans, arachnids, and myriapods, that are characterized by a chitinous exoskeleton and a segmented body to which jointed appendages are articulated in pairs.
Ash: The residue that remains after a solid waste has burned. Also referred to as bottom ash and fly ash.
Bacteria: Microscopic single-celled organisms lacking a nucleus. They are structured as either rod-shaped, sphere-shaped, or spiral-shaped. They can be aerobic or anaerobic, or facultative anaerobic.
Backyard composting: The on-site process (typically small scale) where the biological decomposition of organic materials such as leaves, grass clippings, brush, and food scraps is processed into a soil amendment.
Beetle mites:
Heavily armored fungus- and needle-eaters.
Best management practices: The most effective and practicable method of preventing or reducing the amount of pollution generated by pollution sources. Often abbreviated as BMPs.
Bioaerosols: Airborne particles of biological origin including bacteria, viruses, fungi and yeasts, pollens, and organic matter.
Bioassay: Appraisal of the biological activity of a substance by testing its effect on an organism and comparing the result with some agreed standard.
Biodiversity: The variability among living organisms on Earth, including the variability within and between species and within and between ecosystems.
Biofiltration: The harnessing of natural processes for volatile organic compounds (VOC) and odor control. Example: an air stream is passed through a biofilter containing microorganisms, which metabolize the VOCs, turning them into carbon dioxide and water.
Bioremediation: The use of plants or microorganisms to clean up contamination and pollution or to solve other environmental problems, and return the environment to its original condition.
Biosolids: The nutrient-rich organic byproduct material resulting from the treatment of sewage sludge and wastewater.
CAFO: Combined animal feeding operation (CAFO). Animal feeding operations (AFOs) are livestock-raising operations, such as hog, cattle and poultry farms, which confine and concentrate animal populations and their wastes. CAFO is the largest category of AFO with greater than 1,000 "animal units" and is a significant contributor to the pollution of waters in the U.S.
Casing layer: A moist layer of peat moss mixed with a small amount of calcium carbonate that growers apply over mycelium to retain moisture and provide a growing surface for mushrooms.
Catchment: a) A catching or collecting of water, especially rainwater, b) A structure, such as a basin or reservoir, used for collecting or draining water, c) The amount of water collected in such structure, d) A catchment area.
Cellobiose: A disaccharide obtained by the hydrolysis of cellulose by cellulase. Formula: C12H22O11
Cellulase: Any enzyme that converts cellulose to the disaccharide cellobiose.
Cellulose: The main substance in the cell walls of plants, which is used in making paper, artificial fibers, and plastics.
Chitin, (pronounced ktin): Main component of the cell walls of arthropods, found in the outer skeleton of insects, crabs, and lobsters and in the internal structures of other invertebrates.
CNMP: Comprehensive Nutrient Management Plan is a conservation plan that is unique to animal feeding operations and which incorporates environmental practices to utilize animal manure and organic by-products as a beneficial resource to ensure that both production and natural resource protection goals are achieved.
Co-composting: The process of blending biosolids with manure or other green waste materials to produce compost. Co-composting includes both the active and curing phases of the composting process.
Compaction: In soil, compaction occurs when weight of grazing animals/livestock or heavy machinery compresses the soil. The soil then is less able to absorb water.
Compost: The product resulting from the decomposition of organic material. Material used to make compost includes landscape trimmings, agricultural crop residues, paper pulp, food scrap, wood chips, manure, and biosolids. These are typically referred to as feedstock.
Composting: The biological decomposition process of organic materials such as leaves, garden waste, coffee grounds, grass clippings, brush, and food waste into a soil amendment.
Construction and demolition waste: Waste from building materials such as rubble, lumber, wire, sheet metal, and miscellaneous metal parts.
Conversion technology: Term used for the technologies that convert unwanted organic materials into high-value products such as energy, alternative fuels, solvents, and other products.
Cover crop: A crop, such as clover, planted between periods of regular crop production to control weeds, prevent soil erosion, and provide humus or nitrogen to the soil.
Crown: The junction of root and stem, usually at the level of the ground.
Decomposer: An organism that feeds on and breaks down organic materials into simpler chemical compounds.
Decomposition: The process by which organic materials chemically break down into simpler compounds.
Dewatering: Removal of water from solid waste and sludge via mechanical or thermal means.
Disaccharide: Any of a class of sugars, such as maltose, lactose, and sucrose, having two linked monosaccharide units per molecule.
Ecosystem: All the living things in an area and the way they affect each other and the environment.
Exoskeleton: An external supportive covering of an animal such as a crab or insect (as an arthropod).
Feedstock: The raw material used for chemical or biological processes. For example, feedstock used for making compost could include grass clippings, leaves, food scraps, plant trimmings, straw, and animal bedding.
Foliage: The leaves of plants or trees.
Food material: Material acquired for animal or human consumption, is separated from the municipal solid waste stream, and does not meet the definition of “agricultural material.”
Food scraps: All excess food, including surplus, spoiled, or unsold food such as vegetables and culls (lower quality vegetables or trimmings such as onion peels or carrot tops), as well as plate scrapings. Food scraps also are commonly called food remnants, food residuals, or food waste.
Food waste: Refers to all surplus food scraps. The term has fallen out of favor with some composters, who prefer to view this material as a resource rather than as waste material. However, this term is interchangeable with food scraps.
Food Web: The totality of interacting food chains within an ecosystem.
Fulvic acid: A yellow to yellow-brown humic substance that is soluble in water under all pH conditions.
Fungi: Saprophytic and parasitic plants that lack chlorophyll and include molds, rusts, mildews, smuts, and mushrooms.
Grasscycling: The natural recycling of grass by leaving clippings on the lawn when mowing. Grass clippings will quickly decompose, returning valuable nutrients to the soil.
Green material: Green material includes, but is not limited to, yard trimmings, untreated wood wastes, natural fiber products, and construction and demolition wood waste. Green material does not include food material, biosolids, mixed solid waste, material processes from commingled collection, wood containing lead-based paint or wood preservative, and mixed construction or mixed demolition debris.
Green waste: A term used to refer to urban landscape waste generally consisting of leaves, grass clippings, weeds, yard trimmings, wood waste, branches and stumps, home garden residues, and other miscellaneous organic materials.
Hazardous Waste: This includes radioactive substances, toxic chemicals, explosives, biological waste (e.g. from hospitals), and flammable waste.
Heavy Metals: A commonly hazardous waste that can damage organisms at low concentrations, including cadmium, mercury, and lead, and which can be found in the waste stream in batteries, televisions, paints, and ink.
Homopteran: Any of an order or suborder of insects (as cicadas, aphids, and scale insects) that have sucking mouthparts, able to pierce plant tissue and suck liquid out.
Humic Acid: Any of various organic acids obtained from humus.
Humus: The organic component of soil formed by the decomposition of animal or vegetable matter.
Hydrolysis: A catch-all term for any reaction in which the water molecule is split.
Hyphae: The plural of hypha, which is any of the filaments that constitute the body (mycelium) of a fungus.
Industrial sludge: Sludge from factories, manufacturing facilities, and refineries. This type does not include any subtypes. For example, this type includes paper pulp sludge and water treatment filter cake sludge.
Inoculate: To implant microorganisms onto or into a culture medium.
Inorganic matter: Refers to non-living source such as rocks, minerals or sand, of nonbiological origin.
Integrated pest management (IPM): Integrated pest management (IPM) is an ecosystem-based strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation, modification of cultural practices, and use of resistant varieties. Pesticides are used only after monitoring indicates they are needed according to established guidelines, and treatments are made with the goal of removing only the target organism.
Invertebrate: An organism lacking a spinal column.
Laminarinase: A polysaccharide that is found in various brown algae and yields only glucose on hydrolysis.
Leachate: A water that has percolated through a solid waste, such as a landfill.
Leftovers: In terms of food scraps or food waste, may refer to food prepared in excess that has not been served but may be collected for a human food donation or recovery program. Leftovers can also refer to plate scrapings that are not appropriate for human consumption.
Lerp Psyllid: A plant-moisture sucking homopterans in the insect family Psyllidae. Redgum lerp psyllid nymphs (immature) form a cover called a "lerp," which is a small white, hemispherical cap composed of solidified honeydew and wax. The UC Berkeley Biological Control of the Red Gum Lerp Psyllid page provides additional information on Lerp Psyllid.
Lignin: A complex polymer, the chief non-carbohydrate constituent of wood that binds to cellulose fibers and hardens and strengthens the cell walls of plants.
Manure: Agricultural material and means accumulated herbivore or avian excrement. This includes feces and urine, and any bedding material, spilled feed, or soil that is mixed with feces or urine.
(Gr.--Cold loving)
Describes bacteria which are active in the temperature range between 40-110 degrees Fahrenheit, but thrive between 70-90 degrees Fahrenheit. Most of the decomposition that takes place in a compost pile is mesophilic.
Methane: A gas created naturally in marshes and bogs, as well as landfills. Considered a potent greenhouse gas.
Microbial spore suspensions: Microscopically visible particles dispersed throughout a less dense liquid from which they are easily filtered but not easily settled because of system viscosity or molecular interactions.
Microorganisms: Microscopic living organisms that digest organic material through metabolic activity.
Mold: A superficial (often woolly) fungus that grows especially on damp or decaying organic matter or on living organisms.
Monosaccharides: A sugar that is not decomposable to simpler sugars by hydrolysis. The simplest form of sugar.
Morphology: The form and structure of an organism or any of its parts
Mulch: A layer of organic material that is spread over the bare surface of soil to block the loss of moisture and to discourage the growth of weeds. Typically applied around plants to minimize moisture evaporation. Mulch is the term for non-composted materials, such as shredded or chipped bark.
Municipal organic materials: Organic materials generated by residential, business, institutional, and agricultural sources, which are then collected and sent to city and county waste facilities.
Municipal solid waste (MSW):   Garbage. Refuse with the potential for energy recovery; includes residential, commercial, and institutional wastes.Means the material part of the municipal solid waste stream and is mixed with or contains nonorganic, processed industrial materials, or plastics. Compostable material that contains mixed demolition or mixed construction debris shall be considered mixed solid waste.
Mycelium: The body of a fungus, composed of many threads of tissue. Mushrooms do not reproduce by seed, but by spores. The spores germinate to produce threadlike structures known as hyphae. Collectively, a mass of hyphae are known as the mycelium.
Myriapoda: Any of a group of arthropods having the body made up of numerous similar segments nearly all of which bear true jointed legs and including the millipedes and centipedes.
Native plant: The native plants of a given area are those that grew there prior to European contact. Native plants have co-evolved with animals, fungi, and microbes to form a complex network of relationships. These plants are the foundation of native ecosystems, or natural communities.
Nematode: Any un-segmented worm of the class Nematoda, having a tough outer cuticle. The group includes free-living forms and disease-causing parasites, such as the hookworm and filaria.
Also called: nematode worm, roundworm
Nitrates: A compound containing nitrogen and oxygen that can exist in the atmosphere or in water and that can have harmful effects on humans and animals at high concentrations.
Non-Aerated: No air or circulation of air.
Nonpoint source pollution: Diffuse discharges of waste throughout the natural environment which are a major cause of water pollution. Difficult to pinpoint physically, but can be classified by type: urban runoff, agriculture, mining, septic tank leach fields, and silviculture.
Organic matter: Material that comes from organisms that were once alive, or derived from or produced through the biological activity of a living thing.
Old corrugated container (OCC): A fabricated container made from linerboard placed around a corrugated medium.
Parasite: An organism that inhabits a living host in a symbiotic relationship, for existence or support. Typical examples include hookworms, tapeworms, and some mites. In plants, a parasitic plant is one that gets its sustenance from an established host plant.
Pathogen: Any organism or infectious agent, capable of causing disease or infection. In the composting process, (found in animal waste material), pathogens are killed by the high temperatures (131 degrees Fahrenheit or higher for three days).
Phyllosphere: The three-dimensional micro-environmental space surrounding a leaf.
Phylloxera: Scientific Name: Daktulosphaira vitifoliae--a tiny aphid-like insect that feeds on Vitis vinifera grape roots, stunting growth of vines or killing them.
Phylum: A series of animals or plants genetically connected by one or more fundamental characteristics that set them apart from all other animals and plants and forming a primary category of the animal or plant kingdom.
Phytophthora cinnamomi: A destructive parasitic fungi causing root rot in plants.
Phytophthora ramorum: A newly identified plant pathogen that causes Sudden Oak Death in a variety of hosts.
Polysaccharide: A carbohydrate that can be decomposed by hydrolysis into two or more molecules of monosaccharides especially: any of the more complex carbohydrates (as cellulose, starch, or glycogen).
Postconsumer food scraps: Food that has been served to diners but is not eaten; also called plate scrapings. This may include vegetables, salad dressings, sauces, cheese, meat, and bones, as well as nonfood items, such as napkins. If the nonfood items are not separated from the food, these and other nonfood contaminants like straws, cups, and plastic utensils will become a part of this blend.
Preconsumer food scraps: Preconsumer scraps may include food processing wastes such as vegetable culls, brewery by-products, coffee grounds, or kitchen preparation wastes. Restaurants, for example, often cut off inedible portions of vegetables in food preparation. This can include carrot tops, potato peels, lettuce leaves, broccoli stems, or similar scraps.
Protozoa: Unicellular or single-celled animals which have varied morphology and physiology, and often complex life cycles. Represented in almost every kind of habitat.
(Gr.--Warmth loving)
Describes bacteria which are active in a low temperature range (below 65 degrees Fahrenheit), but thrive around 55 degrees Fahrenheit.
Putrescine: Produced by the breakdown of amino acids as organisms break down.
Rendering: Related to animal waste, a process that breaks down and converts animal tissue into a usable commodity. Rendering operations can make edible products such as canned pet food, or non-edible products like bone meal.
Rhizome: An underground, horizontal plant stem that produces shoots above and roots below, and is distinguished from a true root in possessing buds, nodes, and usually scale-like leaves. Examples of plants with underground rhizomes include ginger and bamboo; plants with rhizomes that grow above ground include some iris species and ferns.
Rhizosphere: The below-ground area that surrounds the root surface of plants, where root secretions occur and microorganisms consume sugars released by the roots.
Saprophages: Also known as detritus feeders. Refers to organism that contributes to decomposition, obtaining food by absorbing dissolved organic material.
Side dressing: The application of fertilizer or organic matter around a plant, the material being left on the soil surface rather than being dug in. Also known as top dressing.
Silviculture: The care and cultivation of forest trees; forestry.
Soil amendment: A material, such as organic matter or sand, mixed into soil to improve growing conditions.
Soil biology: The study of the organisms and their activity in soil, this includes bacteria, worms, fungi, and nematodes.
Soil food web: A group of plants, soil, organic matter, and organisms that thrive within a system.
Soluble: Susceptible to being dissolved in or as if in a liquid and especially water.
Spawn: The term used for the combination of mycelium and substrate is spawn. This can be thought of as the vegetative part of the mushroom.
Stolon: A horizontal stem at or just below the surface of the ground that roots at the nodes and produces new plants. Also called "runners."
Substrate: Any combination of materials that provide support, water retention, aeration, or nutrient retention for plant growth. In this instance, substrate is compost into which mushroom spawn is distributed.
Sudden Oak Death: A disease infecting oaks and several other ornamental plants that were noticed in recent years in coastal California and a small geographic area of Oregon. The United States Department of Agriculture website provides additional information on Phytophthora ramorum.
Textiles: Items made of thread, yarn, fabric, or cloth. This includes clothes, fabric trimmings, draperies, and all natural and synthetic cloth fibers. This does not include cloth- covered furniture, mattresses, leather shoes, leather bags, or leather belts.
Thatch: A mat of undercomposed plant material (as grass roots) accumulated next to the soil in a grassy area (as a lawn)
(Gr.--Heat loving)
Heat-loving, applied especially to certain bacteria requiring high temperatures for normal development.
Tilth: The condition of soil or land that has been tilled, especially with respect to suitability for promoting plant growth.
Tire: A pneumatic tire or solid tire manufactured for use on any type of motor vehicle.
Trommel: A revolving cylindrical sieve used for screening or sizing compost and mulch.
Vector Control: Related to rats, insects, birds, and vermin. Methods used to control and reduce the risk of exposure to these pests that may transmit disease pathogens to humans.
Vermicomposting: The process whereby worms feed on slowly decomposing materials (e.g., vegetable scraps) in a controlled environment to produce a nutrient-rich soil amendment. Additional terms for the soil amendment are worm castings or worm manure. This material is rich in nutrients and is an excellent soil conditioner. Species typically used for vermicomposting include Red Wigglers and European nightcrawlers.
Volatile Organic Compound (VOC): Carbon-containing compounds that evaporate into the air (with a few exceptions). VOCs contribute to the formation of smog and/or may themselves be toxic. VOCs often have an odor. Typical liquids that release VOCs include gasoline, diesel fuel, pesticides, cleaning supplies, glues, and solvents used in paints.
Watershed: The total land area that contributes water from rain or snowmelt down to a body of water, such as a river, reservoir, wetland, stream, lake, or ocean. Synonymous with drainage area, drainage basin, and catchment.
Wood-overs: Also called compost-overs, these are large, woody parts of the compost pile that have not completely broken down and will not pass through a minus one-half inch trommel screen.
Wood waste: Solid waste consisting of wood pieces or particles which are generated from the manufacturing or production of wood products, harvesting, processing, or storage of raw wood materials, or construction and demolition activities.
Xeriscaping: The practice of landscaping with slow-growing, drought-tolerant plants to eliminate the need for irrigation and lower the need for water consumption.
Yard trimmings: Wastes generated from the maintenance or alteration of public, commercial or residential landscapes including, but not limited to, yard clippings, leaves, tree trimmings, prunings, brush, and weeds.

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Last updated: February 9, 2010
Organic Materials Management