Compost
As organic matter decomposes, it recomposes, yielding a composition known as compost. Compost is a dark, crumbly, earthy-smelling material. Composting is a controlled, aerobic (oxygen-required) process that converts organic waste into a nutrient-rich soil amendment or mulch. Microorganisms feed on organic waste -- the compost pile -- during this process. They need carbon to generate heat, nitrogen to grow and reproduce, water to digest materials, and oxygen to breathe.[1]
Integral to Food Sovereignty.
Definition
late 14c., compote, "mixture of stewed fruits, a preserve," from Old French composte "mixture of leaves, manure, etc., for fertilizing land" (13c.), also "condiment," from Vulgar Latin *composita, noun use of fem. of Latin compositus, past participle of componere "to put together," from com "with, together" (see com-) + ponere "to place".
The fertilizer sense is attested in English from 1580s, and the French word in this sense is a 19th century borrowing from English. The condiment sense now goes with compote, a later borrowing from French.[2]
Historical
Technical
Per the Practical Handbook of Compost Engineering the process of "composting" is, technically:
the biological decomposition and stabilization of organic substrates, under conditions that allow development of thermophilic temperatures as a result of biologically produced heat, to produce a final product [=compost] that is stable, free of pathogens and plant seeds, and can be beneficially applied to land. Thus, composting is a form of waste stabilization, but one that requires special conditions of moisture and aeration to produce thermophilic temperatures . . . considered to be above about 45°C (113°F). Maintenance of thermophilic temperatures is the primary mechanism for pathogen inactivation and seed destruction.[3]
Production
Composting organisms require four equally important ingredients to work effectively:
- Brown Earth (carbon) provides fuel; the microbial oxidation of carbon produces the heat required for other parts of the composting process. High carbon materials tend to be brown and dry.
- Green Earth (nitrogen) feeds the microbiome driving this heat reaction through its growth + reproduction. High nitrogen materials tend to be green and wet, but include colorful foods.
- Air oxidizes the carbon, stoking the digestive fire. Aerobic bacteria typically need oxygen levels above 5% to compost.
- Water nourishes the decomposition activity, although too much will cause anaerobic conditions.
Feedstocks
GREENS + BROWNS
Biochar
When biochar is added to fresh compost feedstock prior to the composting process (co-composting), multiple benefits have been shown to occur. Emissions of greenhouse gases and odor during composting should decrease, as does the time needed for the compost to mature. Further, the properties of the co-composted product are improved, making it more suitable for agroecological applications.[5] These benefits include increased water retention[6], microbial habitat[7], soil texture[8], nutrient retention[9], and carbon sequestration.[10]
Reactors
Commons
- Toilets
- Moundculture
Household
- Bokashi
Ag / Industry
- Windrow
The windrow system is the most popular example of a nonreactor, agitated solids bed system. Mixed feedstocks are placed in rows and turned periodically, usually by mechanical equipment. Height, width, and shape of the windrows vary depending on the nature of the feed material and the type of equipment used for turning. Oxygen is supplied primarily by natural ventilation resulting from the buoyancy of hot gases in the windrow, and to a lesser extent, by gas exchange during turning. In the forced aeration windrow system, oxygen transfer into the windrow is aided by forced or induced aeration from blowers. In most composting literature the term "forced" aeration is used regardless of whether aeration is forced or induced. Strictly speaking, forced aeration applies to cases where ambient air is forced into the material under positive pressure. Induced aeration applies to cases where gases are pulled from the material under negative pressure. In either case, periodic agitation by turning is used to restructure the windrow. As a result, considerable mixing can be expected along the height and width of the row, but little mixing will occur along the length.[3]
- BEAM: Biologically Enhanced Agricultural Management
- high in mycelium and carbon burial - alternative to "holistic management"
Application
Sources
- ↑ 1.0 1.1 https://www.epa.gov/recycle/composting-home
- ↑ Online Etymology Dictionary, "Compost" https://www.etymonline.com/word/compost
- ↑ 3.0 3.1 Haug, R.T. and Haug, H.T. (1993) Practical Handbook of Compost Engineering. Lewis Publishers, Boca Raton.
- ↑ https://en.wikipedia.org/wiki/Compost [accessed 2-2-23]
- ↑ https://s3.us-west-2.amazonaws.com/wp2.cahnrs.wsu.edu/wp-content/uploads/sites/32/2022/01/Biomass2Biochar-ExecutiveSummary1.1.pdf, Biomass to Biochar: Maximizing the Carbon Value, v1.1 (January 2022), p. 14; The Center for Sustaining Agriculture and Natural Resources
- ↑ https://www.frontiersin.org/articles/10.3389/fpls.2015.00733/full
- ↑ http://ijrsset.org/pdfs/v5-i5/2.pdf
- ↑ https://pubs.acs.org/doi/abs/10.1021/acssuschemeng.9b03536>
- ↑ https://pubs.acs.org/doi/abs/10.1021/acssuschemeng.9b03536>
- ↑ https://www.nature.com/articles/s41598-019-41953-0