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Etymology
The word manure came from Middle English "manuren" meaning "to cultivate land," and initially from French "main-oeuvre" = "hand work" alluding to the work which involved manuring land.
Types
There are two main classes of manures in soil management: green manures and animal manures. Compost is distinguished from manure in that it is the decomposed remnants of organic materials (which may, nevertheless, include manure).
Most animal manure is feces — excrement of plant-eating mammals (herbivores) and poultry — or plant material (often straw) which has been used as bedding for animals and thus is heavily contaminated with their feces and urine.
Green manures are crops grown for the express purpose of plowing them under. In so doing, fertility is increased through the nutrients and organic matter that are returned to the soil. Leguminous crops, such as clover, also "fix" nitrogen through rhizobia bacteria in specialized nodes in the root structure.
Other types of plant matter used as manure or fertilizer include: the contents of the rumens of slaughtered ruminants; spent hops left over from making beer.
Uses of manure
Manure has been used for centuries as a fertilizer for farming, as it is rich in nitrogen and other nutrients which facilitate the growth of plants. Liquid manure from pig/hog operations is usually knifed (injected) directly into the soil to reduce the unpleasant odors. Manure from hogs and cattle is spread on fields using a Manure spreader. Due to the relatively lower level of proteins in grasses, which herbivores eat, cattle manure has a milder smell than the dung of carnivores — for example, elephant dung is practically odorless. However, due to the quantity of manure applied to fields, odor can be a problem in some agricultural regions. Poultry droppings are harmful to plants when fresh but after a period of composting are valuable fertilizers.
The dried manure of animals has been used as fuel throughout history. Dried manure (usually known as dung) of cow was, and still is, an important fuel source in countries such as India, while camel dung may be used in treeless regions such as deserts. On the Oregon Trail, pioneering families collected large quantities of "buffalo chips" in lieu of scarce firewood. It has been used for many purposes, in cooking fires and to combat the cold desert nights.
Another use of manure is to make paper, this has been done with dung from elephants where it is a small industry in Africa and Asia, and also horses, llamas, and kangaroos. Other than the llama, these animals are not ruminants and thus tend to pass plant fibres undigested in their dung.
In 2008, chemists at the National Institute of Standards and Technology (NIST) developed the first detailed chemical analysis revealing what processing is needed to transform pig manure derived 'crude oil' into fuel for vehicles or heating. Mass production of this type of biofuel could help consume a waste product overflowing at U.S. farms, but it will require a lot of refining.[2] Their analysis is described in the 2008 issue of Fuel.[3]
Precautions
Manure generates heat as it decomposes, and it is not unheard of for manure to ignite spontaneously should it be stored in a massive pile.[4] Once such a large pile of manure is burning, it will foul the air over a very large area and require considerable effort to extinguish. Large feedlots must therefore take care to ensure that piles of fresh manure (faeces) do not get excessively large. There is no serious risk of spontaneous combustion in smaller operations.citation needed
There is also a risk of insects carrying feces to food and water supplies, making them unsuitable for human consumption.
Livestock antibiotics and hormones
In 2007, a University of Minnesota study [5] indicated that foods such as corn, lettuce and potatoes have been found to accumulate antibiotics from soils spread with animal manure that contains these drugs, and organic foods are most likely to contain these drugs because manure is often the main source of crop nutrients for organic food production.
A two part webcast series about the science available on potential risks and best management practices related to antibiotics and hormones from animal manure is available at [1].
See also
Notes
- ^ Ronald Fisher seems to have used the word manure systematically for what we would call fertilizer today.
- ^ Chemists Get Scoop on Crude ‘Oil’ from Pig Manure Newswise, Retrieved on June 30, 2008.
- ^ Ott LS, Smith BL,Bruno TJ (2008). "Advanced distillation curve measurement: Application to a bio-derived crude oil prepared from swine manure.". Fuel..
- ^ Spontaneous combustion of manure starts 200-acre blaze
- ^ Livestock Antibiotics Can End Up in Human Foods
Further reading
- Anderson, S., and F. Ertug-Yaras. (1998.). "Fuel fodder and faeces: an ethnographic and botanical study of dung fuel use in central Anatolia.". Environmental Archaeology 1: 99–109.
- Charles, M. P. (1998.). "Fodder from dung: the recognition and interpretation of dung derived plant material from archaeological sites". Environmental Archaeology 1: 111–122.
- Fenton, Alexander (1985). "A fuel of necessity: animal manure". Alexander Fenton The Shape of the Past. Essays in Scottish Ethnology: 96-111, Edinburgh: John Donald.
- Miller, N. F. (1984.). "The use of dung as fuel: an ethnographic example and an archaeological application". Paléorient 10: 71–79.
- Winterhalder, B., R. Larsen, and R. B. Thomas. (1974.). "Dung as an essential resource in a highland Peruvian community". Human Ecology 2: 89–104. doi:.
External Links
- Livestock and Poultry Environmental Learning Center, an eXtension community of practice about animal manure management
