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    Compost & Composting Experiments

    Compost & Composting


    Compost is a combination of decomposed plant and animal materials and other organic materials that are being decomposed largely through aerobic decomposition into a rich black soil.

    Composting is the purposeful biodegradation of organic matter, such as yard and food waste.


    Compost is a type of fertilizer that is made from rotting plants. It is easy and cheap to make, as all it really requires is vegetable waste. The vegetable waste is broken down by bacteria (germs), and made into compost.

    To make a compost heap, you need some space fairly far from anyone who might have a problem with the smell. The bottom corner of a garden, or some other place a distance from the house is a good place. Compost heaps should also be placed on soil, or grass: a paved yard or concrete are bad places. The compost heap should not be in a dark or closed corner.

    The best base for a compost heap is a layer of sand, bricks or gravel about 1m long by 1m wide. This is not needed, but it can be a good idea. If using bricks, leave spaces to allow the air to move through. It also allows for the water to run away. The best compost heaps have lots of little spaces inside, to allow air to move around and encourage.

    Once the first layer is down, one can begin adding the waste.

    Some good types of waste are:

    • Vegetable/fruit peels and scraps
    • Spoiled, rotten or moldy fruit
    • Cut grass
    • Leaves
    • Straw
    • Sawdust
    • Eggshells

    Adding meat scraps is a bad idea, as they rot slowly, smell bad and attract rats and other vermin. Human or pet feces is also a very bad idea, as this can transmit disease. Waste from plants that have died of disease is also bad. The disease can spread to the plants that the compost is used with.

    When making a compost heap, different types of waste should be layered. A layer of cut grass can be followed by a layer of vegetable waste and table scraps.

    Watering the compost heap is a good idea, especially in dry areas. The water helps encourage the waste to rot and turn into compost.

    In anywhere from 3 to 6 months, the compost will be ready. The compost is ready when it smells like thick earth, with no smell of decay or rot. Of course, if you've been adding waste all this time, the compost will all be at the bottom of the heap, and will have to be dug out.

    The stuff that hasn't rotted can be used as part of a new compost heap.

    Topics of Interest

    Compost is a combination of decomposed plant and animal materials and other organic materials that are being decomposed largely through aerobic decomposition into a rich black soil. The process of composting is simple and practiced by individuals in their homes, farmers on their land, and industrially by industries and cities.

    Compost soil is very rich soil and used for many purposes. A few of the places that it is used are in gardens, landscaping, horticulture, and agriculture. The compost soil itself is beneficial for the land in many ways, including as a soil conditioner, a fertilizer to add vital humus or humic acids, and as a natural pesticide for soil. In ecosystems, compost soil is useful for erosion control, land and stream reclamation, wetland construction, and as landfill cover (see compost uses).

    History: Composting as a recognized practice dates to at least the early Roman era since Pliny the Elder (AD 23-79) who refers to compost in his writings. Traditionally, composting was to pile organic materials and let them stand for about a year, or until the next planting season, at which time the materials would be ready for soil application. The main advantage of this method is that little working time or effort is required from the composter and it fits in naturally with agricultural practices in temperate climates. Disadvantages (from the modern perspective) are that space is used for a whole year, some nutrients might be leached due to exposure to rainfall, and disease producing organisms, some weeds, weed seeds and insects may not be adequately controlled.

    Ingredients: Compost educator displaying finished compost to student groupGiven enough time, all biodegradable material will oxidize to "compost". One objective of composting today is to treat readily degradable materials that may otherwise enter landfills, and decompose anaerobically, releasing greenhouse gases. Most small-scale domestic systems are not maintained at the thermophilic temperatures required to eliminate possible pathogens and disease vectors, or deter vermin, therefore pet droppings, meat scrap, and dairy products are best left to larger scale high-rate, aerobic composting systems. A local organics recycling facility may operate such a system. However, hobby animal manure (horses, goats, sheep, chickens), fruit and vegetable food materials and garden materials are excellent raw materials for home composting.

    Uses: Compost is generally recommended as an additive to soil, or other matrices such as coir and peat, as a tilth improver, supplying humus and nutrients. It provides a rich growing medium, or a porous, absorbent material that holds moisture and soluble minerals, providing the support and nutrients in which plants can flourish, although it is rarely used alone, being primarily mixed with soil, sand, grit, bark chips, vermiculite, perlite, or clay granules to produce loam.

    As an alternative to landfilling: As concern about landfill space increases, worldwide interest in recycling by means of composting is growing, since composting is a process for converting decomposable organic materials into useful stable products. Industrial scale composting in the form of in-vessel composting, aerated static pile composting, and anaerobic digestion takes place in most Western countries now, and in many areas is mandated by law. There are process and product guidelines in Europe that date to the early 1980s (Germany, Holland, Switzerland) and only more recently in the UK and the US. In both these countries, private trade associations within the industry have established loose standards, some say as a stop-gap measure to discourage independent government agencies from establishing tougher consumer-friendly standards. The USA is the only Western country that does not distinguish sludge-source compost from green-composts, and by default in the USA 50% of states expect composts to comply in some manner with the federal EPA 503 rule promulgated in 1984 for sludge products. Compost is regulated in Canada and Australia as well.

    A composting toilet is an aerobic processing system that treats excreta, typically with no water or small volumes of flush water, via composting or managed aerobic decomposition. This is usually a faster process than the anaerobic decomposition at work in most wastewater systems, such as septic systems.

    Home composting is the small scale domestic application of the principles of sustainable, biodegradable waste management, i.e. composting. The general principles involved in composting apply to any scale, from "backyard" to industrial, but the techniques will vary for each with the size of the waste stream, the cost, amount of effort, and the organization required. Industrial scale systems are invariably capital and/or labor intensive, but on the home or small-farm scale, composting can be managed to require varying outlay of capital and labor. For the small urban household, an indoor Bokashi or worm bin may suffice, for a suburban property with a larger yard and a food garden, a bin system would be preferable, while in small farm settings, a seasonal windrow system might be called for.

    Vermicompost is the product or process of composting utilizing various species of worms, specifically red wigglers, white worms, and earthworms creating the heterogeneous mixture of decomposing vegetable or food waste, bedding materials, and pure vermicast produced during the course of normal vermiculture operations. Vermicast, similarly known as worm castings, worm humus or worm manure, is the end-product of the breakdown of organic matter by the species of earthworm.

    Bokashi is a method of intensive composting. It can use an aerobic or anaerobic inoculation to produce the compost. Once a starter culture is made, it can be re-used, like yogurt culture. Since the popular introduction of effective microorganisms (EM), Bokashi is commonly made with only molasses, water, EM, and wheat bran.

    Composting is the purposeful biodegradation of organic matter, such as yard and food waste. The decomposition is performed by micro-organisms, mostly bacteria, but also yeasts and fungi. In low temperature phases a number of macro-organisms, such as springtails, ants, nematodes, isopods and red wigglers also contribute to the process, as well as soldier fly, fruit flies and fungus gnats. There are a wide range of organisms in the decomposer community.

    Composting upcycles organic kitchen and yard waste and manures into an extremely useful humus-like, soil end product, permitting the return of vital organic matter, nutrients, and particularly bacteria, that are vital to plant nutrition to the soil. Managed aerobic composting arranges environmental conditions so they are optimal for the natural processes to take place. There is a popular expression: "compost happens", but it is helpful to engineer the best possible circumstances for large amounts of organic waste to decompose quickly and efficiently, with the greatest conservation of useful nutrients and mass. Uncontrolled composting is when compost "happens", and although that may be functional in some circumstances, as with forest floor detritus, a neglected heap of kitchen and yard wastes will more likely result in "smells happen", or "rodents happen" long before useful compost does.

    Composting organisms require four equally important things to work effectively:

    • Carbon ("C" or carbohydrates), for energy - the microbial oxidation of carbon produces the heat. High carbon materials tend to be brown and dry.
    • Nitrogen ("N" or protein), to grow and reproduce more organisms to oxidize the carbon. High nitrogen materials tend to be green (or colorful, like fruits and vegetables) and wet.
    • Oxygen, for oxidizing the carbon, the decomposition process.
    • Water, in the right amounts to maintain activity without causing anaerobic conditions.

    Certain ratios of these elements will provide beneficial bacteria with the nutrients to work at a rate that will heat up the pile. In that process much water will be released as vapor ("steam"), and the oxygen will be quickly depleted, explaining the need to actively manage the pile. The hotter the pile gets, the more often added air and water is necessary; the air/water balance is critical to maintaining high temperatures until the materials are broken down. At the same time, too much air or water also slows the process, as does too much C (or too little N).

    Active (Intensively Managed) Composting: Hot thermophilic composting is essential with some materials, such as meat and other animal products, dairy products, eggs, grease, cooking oil, manure of non-herbivores, and residuals from the treatment of wastewater, in order to kill pathogens; but these materials are not generally recommended in home composting because of the likelihood of creating odors and attracting rodents. Human waste can be composted by industrial methods as well as composting toilets. When high temperatures are reached, the resulting compost can be safely used for agricultural or horticultural purposes, providing local health regulations are met. Humanure fertilizer (as opposed to night soil) is used throughout the developing world and is becoming more accepted as a garden amendment in the developed world.

    Passive (Non-intensive) Composting: Ambient composting, typical of "sheet composting" methods espoused in early organic farming, usually results in temperatures not climbing substantially above background temperatures, hence the expression ambient. It is slower, and is the more common type of composting in domestic gardening, particularly in home composting where compost piles are less than 1.3 cu. yd (1 cubic meter) in volume. Such composting systems may be in open or closed containers of wood or plastic, or in open exposed piles. Kitchen scraps are put in the garden compost bin and left untended. This scrap bin can have a very high water content which reduces aeration, and may become odorous. To improve drainage and airflow, and reduce odor, carbon-rich materials, or 'browns', such as wood chips, shredded bark, leaves, or twigs may be added to mix and cover each wet addition, or holes made occasionally in the pile. The amount of attention may vary from none through occasional to "regular".

    An unusual form of composting in nature is seen in the case of the mound-builders (megapodes) of the Australasian region. These Megapodes are fowl-sized birds famous for building nests in the form of compost heaps containing organic litter, in which they incubate their eggs. The male birds work assiduously to maintain the correct incubation temperatures, by adding and removing litter from the compost pile.

    Industrial composting systems are increasingly being installed as a waste management alternative to landfills, along with other advanced waste processing systems. Mechanical sorting of mixed waste streams combined with anaerobic digestion or in-vessel composting, is called mechanical biological treatment, increasingly used in developed countries due to regulations controlling the amount of organic matter allowed in landfills. Treating biodegradable waste before it enters a landfill reduces global warming from fugitive methane; untreated waste breaks down anaerobically in a landfill, producing landfill gas that contains methane, a potent greenhouse gas.

    Compost is an important source of nutrients commonly used in modern agriculture. Through steaming, compost can be sanitized and prepared for further use.

    Source: Wikipedia (All text is available under the terms of the GNU Free Documentation License and Creative Commons Attribution-ShareAlike License.)

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