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Compost (Wikipedia)

Community-level composting in a rural area in Germany
Backyard composter

Compost (/ˈkɒmpɒst/ or /ˈkɒmpst/) is made by decomposing organic materials into simpler organic and inorganic compounds in a process called composting. This process recycles various organic materials otherwise regarded as waste products. A good compost is rich in plant nutrients and beneficial organisms.

Compost is used to improve the soil fertility in gardens, landscaping, horticulture, urban agriculture and organic farming. The benefits of compost include providing nutrients as fertilizer to the crop, acting as soil conditioner, increasing the humus or humic acids content of the soil, and introducing beneficial colonies of microbes in the soil. The natural interaction of the soil, plant roots and nutrient / microorganisms of compost improves the soil structure. An improved soil structure will increase the soil water retention ability and control soil erosion. Compost can be used for land and stream reclamation and ecofriendly wetland construction. As a landfill cover, compost provides a healthy utilization of waste organic materials.

At its simplest level, composting requires gathering a mix of 'Greens' and 'Browns'. Greens are materials rich in nitrogen such as leaves, grass, and food scraps. Browns are more woody materials rich in carbon-like stalks, paper, and wood chips. The materials are wetted to break them down into humus, a process that occurs over a period of months. Most organic standards demand at least a 60 days composting process, however, composting can also take place as a multi-step, closely monitored process with measured inputs of water, air, and carbon- and nitrogen-rich materials. The decomposition process is aided by shredding the plant matter, adding water, and ensuring proper aeration by regularly turning the mixture when open piles or "windrows" are used. Fungi, earthworms and other detritivores further break up the organic material. Aerobic bacteria and fungi manage the chemical process by converting the inputs into heat, carbon dioxide, and ammonium.

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