Proper moisture is also vital for the health of the microorganisms that help with the composting process. A moisture content between 40 and 60 percent provides enough dampness to prevent the microorganisms from becoming dormant but not enough so that oxygen is forced out of the pile. The amount of oxygen within the compost pile is also important as an oxygen deficit leads to anaerobic microorganisms taking over, and that can lead to a stinky compost pile.
Oxygen can be added into the compost pile by stirring or turning over the pile. Note: The USDA recommends burying food waste if using an open-composting pile to deter unwanted pests looking for a free meal, such as flies, rodents and raccoons. Commercial composting companies also collect products such as paper carry-out containers for food and compostable dinnerware and flatware that are specifically labeled BPI Certified Compostable.
Dairy products, eggs, meat products and fats are typically not recommended for the composting pile, but there are many larger commercial composting facilities that are well-suited for dealing with the smells and pathogens that may exist in these products.
To help with the more complex waste, livestock manure is often added to commercial composting sites to help increase the heat and the rate of composting. According to North Dakota State University , livestock manure from herbivores , including cows, sheep and goats, already contains a high amount of nitrogen and many of the aerobic microorganisms that are essential to composting.
This type of manure is also typically free of dangerous pathogens that can be found in the manure of meat-eating animals, such as cats and dogs. Many companies are developing more products that can be composted when disposed of, including dinner and flatware , garbage bags and even diapers. Before putting these items in the compost pile, it is important to make sure they are safe to compost at home or accepted by the local compost collector.
Huantian Cao, professor of fashion and apparel studies at the University of Delaware, co-directs a sustainable apparel project that's working on developing compostable apparel. Cao and his team have developed a shoe that is essentially made of mushrooms. The prototype sandal is made from a variety of compostable parts, Cao told Live Science. The midsole is made from a mushroom mycelium composite that can go right into a home composter along with all the food scraps.
The insole and outsole of the shoe are made with biodegradable vegetable-tanned leather and the straps of the sandal are made with cotton, both of which can be composted at larger, commercial composting sites. Randi Cox and Kathy Gutowsky, owners of the commercial composting company, Green Camino , have been composting since they were young and now educate their community about the benefits of composting, whether through use of their company or at home.
Gutowsky said that many of their clients make lifestyle changes to minimize what goes in their waste bins, including not buying products with excess plastic packaging and buying locally when possible. If you don't have access to a commercial composting site, getting started at home is as easy as putting together a pile in the corner of your yard.
Wind-rowing the leaves into long narrow piles one foot high will make the shredding process more efficient. If the mower has an appropriate bag attachment, the shredded leaves can be collected directly.
However, grinding is entirely optional. Temperature of the compost pile is very important to the biological activity taking place. Low outside temperatures slow the activity down, while warmer temperatures speed up decomposition. These high temperatures will help destroy weed seeds and disease organisms within the pile.
There are many organisms that breakdown organic materials. Most are not seen by the human eye, but they are there throughout the process. Others that are large enough to see, are usually associated with the later breakdown stages.
The most important organisms in the breakdown process are the bacteria. The bacteria present in any given pile are dependent upon the raw material present, amount of air in the pile, moisture conditions of the pile, pile temperature and numerous other factors.
Compostable organic materials normally contain a large number and many different types of bacteria, fungi, molds, and other living organisms. Only very limited data are available regarding the variety of different organisms and their specific functions. It appears that more species of bacteria are involved in aerobic decomposition than in anaerobic putrefaction.
Although many types of organisms are required for decomposition of the different materials, the necessary variety is usually present in the materials to be composted, and the organisms thrive when environmental conditions are satisfactory. During decomposition, marked changes take place in the nature and abundance of the biological population. Some of the many species will multiply rapidly at first but will dwindle as the environment changes and other organisms are able to thrive under more varied conditions.
Temperature and changes in the available food supply probably exert the greatest influence in determining the species of organisms comprising the population at any one time. Aerobic composting is a dynamic process in which the work is done by the combined activities of a wide succession of mixed bacteria, actinomycetes, fungi, and other biological populations.
Since each is suited to a particular environment of relatively limited duration and each is most active in decomposition of some particular type of organic matter, the activities of one group complement those of another.
The mixed populations parallel the complex environments afforded by the heterogeneous nature of the compostable material.
Except for short periods during turning, the temperature increases steadily in proportion to the amount of biological activity until equilibrium state of balance with subsequent heat losses is reached, or the material becomes well-stabilized humus-like. In aerobic composting bacteria, actinomycetes, and fungi are the most active.
Thermophilic fungi usually appear after 5 to 10 days, and actinomycetes become prominent in the final stages, when short duration, rapid composting is accomplished. Except in the final stages of the composting period, when the temperature drops, actinomycetes and fungi are confined to a sharply defined outer zone of the stack, 2 to 6 inches in thickness, beginning just under the outer surface.
Some molds also grow in this outer zone. The population of fungi and actinomycetes is often great enough to impart a distinctly grayish white appearance to this outer zone. The sharply defined inner and outer limits of the shell in which actinomycetes and fungi grow during the high temperature active composting period are due to the inability of these organisms to grow at the higher temperatures of the interior of the pile. Frequent turning—such as is sometimes necessary for fly control—inhibits their growth, since the cooler outer shell is turned into the interior before they can develop in large numbers.
Various investigations have shown that many different types of thermophilic bacteria apparently play a major part in decomposing protein and other organic matter. They continue to predominate throughout the process in theinterior of the piles, where temperatures are inhibitory to actinomycetes and fungi.
In spite of being confined primarily to the outer layers and becoming active only during the latter part of the composting period, fungi and actinomycetes play an important role in the decomposition of cellulose, lignins, and other more resistant materials, which are attacked after the more readily decomposed materials have been utilized.
There are many bacteria which attack cellulose. However, in the parts of compost piles populated chiefly by bacteria, cellulose paper breaks down very little, whereas in the layers or areas inhabited by actinomycetes and fungi it becomes almost unrecognizable.
Considerable cellulose and lignin decomposition by actinomycetes and fungi can occur near the end of the composting period when the temperatures have begun to drop and the environment in a larger part of the pile is satisfactory for their growth. It should be noted that since the necessary organisms for composting are usually present and will carry on the process when the environment is suitable, an extensive knowledge of the characteristics of the various organisms is not necessary for understanding a compost pile.
Normal maintenance as described in this manual will help to insure proper balance and numbers of beneficial microorganisms. Most are microscopic, some are large enough to be observed with the unaided eye, but all are beneficial, each having a role in breaking down raw organic matter into finished compost. They are known as decomposers. But there are other microscopic creatures such as actinomycetes, fungi, and protozoa, that also play an important role.
Together, these are chemical decomposers that change the chemistry of the organic wastes. The largerfauna in the heap include mites, millipedes, flatworms, centipedes, sowbugs, snails, slugs, spiders, springtails, beetles, ants, flies, nematodes and, most importantly, earthworms. Collectively, these are called the physical decomposers since they bite, grind, suck, tear and chew the materials into smaller pieces, making them more suitable for the chemical work of the microscopic decomposers.
All of the organisms, from the microscopic bacteria to the largest of the physical decomposers, are part of a complex food chain in the compost pile. They can be categorized as first, second and third level consumers, depending upon whom they eat and by whom they are eaten.
First level consumers attract and become the food of second level consumers, who in turn are consumed by third level consumers. The organisms comprising each level of the food chain serve to keep the populations of the next lower level in check, so that a balance can be maintained throughout the compost. For example, according to Daniel L. Dindal, in Ecology of Compost:. Tiny feather-winged beetles feed on fungal spores.
Nematodes ingest bacteria. Protozoa and rotifers present in water films feed on bacteria and plant particles. Predaceous mites and pseudo- scorpions prey upon nematodes, fly larvae, other mites and collembolans.
Free-living flatworms ingest gastropods, earthworms, nematodes and rotifers. Third level consumers such as centipedes, rove beetles, ground beetles, and ants prey on second level consumers. These creatures function best at medium or mesophilic temperatures, so they will not be in the pile at all times.
These organisms are the initial inhabitants of the pile. Many of them are unseen and come in with the materials that make up the pile. Bacterial populations differ from pile to pile, depending upon the raw materials of the compost, degree of heat, amount of air present, moisture level, geographical location of the pile, and other considerations.
Bacteria are single-celled and can be shaped like a sphere, rod, or a spiral twist. They are so small that it would take 25, bacteria laid end to end to take up one inch on a ruler, and an amount of garden soil the size of a pea may contain up to a billion bacteria.
Most bacteria are colorless and cannot make carbohydrates from sunshine, water, and carbon dioxide the way more complex green plants can.
Some bacteria produce colonies; others are free-living. All reproduce by means of binary fission. In binary fission, the nucleus splits in two and a new cell wall grows crosswise over the middle of the cell. Each half contains one of the two nuclei, so that a new individual is produced from a single bacterial cell. Under the best conditions, a colony of bacteria can multiply into billions in a very short time.
The life span of one generation of bacteria is about 20 to 30 minutes, so that one cell may yield a progeny of billions of individuals in half a day. Bacteria are the most nutritionally diverse of all organisms, which is to say, as a group, they can eat nearly anything. Most compost bacteria are heterotrophic, meaning that they can use living or dead organic materials. Some are so adaptable that they can use more than a hundred different organic compounds as their source of carbon because of their ability to produce a variety of enzymes.
Usually, they can produce the appropriate enzyme to digest whatever material they find themselves on. In addition, respiratory enzymes in the cell membrane make aerobic respiration possible as an energy source for compost bacteria. Since bacteria are smaller, less mobile and less complex than most organisms, they are less able to escape an environment that becomes unfavorable. A decrease in the temperature of the pile or a sharp change in its acidity can render bacteria inactive or kill them.
When the environment of a heap begins to change, bacteria that formerly dominated may be decimated by another species. The characteristically earthy smell of newly plowed soil in the spring is caused by actinomycetes, a higher form of bacteria similar to fungi and molds. Actinomycetes are especially important in the formation of humus. While most bacteria are found in the top foot or so of topsoil, actinomycetes may work many feet below the surface.
Deep under the roots they convert dead plant matter to a peat-like substance. While they are decomposing animal and vegetable matter, actinomycetes liberate carbon, nitrogen and ammonia, making nutrients available for higher plants. They are found on every natural substrate, and the majority are aerobic and mesophilic. The reason bacteria tend to die rapidly as actinomycete populations grow in the compost pile is that actinomycetes have the ability to produce antibiotics, chemical substances that inhibit bacterial growth.
Protozoa are the simplest form of animal organism. Even though they are single-celled and microscopic in size, they are larger and more complex in their activities than most bacteria.
A gram of soil can contain as many as a million protozoa, but a gram of compost has many thousands less, especially during the thermophilic stage. Protozoa obtain their food from organic matter in the same way bacteriado, but because they are present in far fewer numbers than are bacteria, they play a much smaller part in the composting process. Fungi are many-celled, filamentous or single-celled primitive plants. Unlike more complex green plants, they lack chlorophyll, and, therefore, lack the ability to make their own carbohydrates.
Most of them are classified as saprophytes because they live on dead or dying material and obtain energy by breaking down organic matter in dead plants and animals. A biologically active soil is a healthy soil, so as you improve the soil in your garden, you should expect a faster decomposition of organic matter.
Anything that affects the microbes and other living organisms in your soil, as a result, will affect the rate of organic matter break down. Like all living organisms, the creatures in your soil need oxygen to live. Oxygen comes from the air above the soil, so there must be a means for air to penetrate into the soil. Soil with a loose structure allows for ample spaces between soil particles for oxygen to collect. In such soils, organic matter will decompose faster.
The amount of water in the soil, both indirectly and directly, affects the decomposition rate of organic matter.
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