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In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to free range (roam around) and consume wild in order to convert the otherwise indigestible (by human gut) cellulose within grass and other into meat, milk, wool and other , often on land that is unsuitable for arable farming.
Farmers may employ many different strategies of grazing for crop yield: grazing may be continuous, seasonal, or rotational within a grazing period. Longer rotations are found in ley farming, alternating arable and fodder crops; in rest rotation, deferred rotation, and mob grazing, giving grasses a longer time to recover or leaving land fallow. Patch-burn sets up a rotation of fresh grass after burning with two years of rest. Conservation grazing proposes to use grazing animals to improve the biodiversity of a site.
Grazing has existed since the beginning of agriculture; sheep and were domesticated by before the first permanent settlements were constructed around 7000 BC, enabling cattle and to be kept.
Livestock grazing contributes to many negative effects on the environment, including deforestation, extinction of native wildlife, pollution of streams and rivers, overgrazing, soil degradation, ecological disturbance, desertification, and ecosystem stability.
In America, livestock were grazed on Federal lands from the Civil War. The Taylor Grazing Act of 1934 was enacted after the Great Depression to regulate the use of public land for grazing purposes. "History of Public Land Livestock Grazing". Retrieved 1 Dec 2008
A proper land use and grazing management technique balances
It does this by allowing sufficient recovery periods for regrowth. Producers can keep a low density on a pasture, so as not to overgraze. Controlled burning of the land can help in the regrowth of plants. Although grazing can be problematic for the ecosystem, well-managed grazing techniques can reverse damage and improve the land.
On Common land in England and Wales, rights of pasture (grassland grazing) and pannage (forest grazing) for each commoner are tightly defined by number and type of animal, and by the time of year when certain rights can be exercised. For example, the occupier of a particular cottage might be allowed to graze fifteen cattle, four , pony or , and fifty geese, while the numbers allowed for their neighbours would probably be different. On some commons (such as the New Forest and adjoining commons), the rights are not limited by numbers, and instead a 'marking fee' is paid each year for each animal 'turned out'. Forest rights . However, if excessive use was made of the common, for example, in overgrazing, a common would be 'stinted'; that is, a limit would be put on the number of animals each commoner was allowed to graze. These regulations were responsive to demographic and economic pressure. Thus, rather than let a common become degraded, access was restricted even further.
Grazer urine and faeces "recycle nitrogen, phosphorus, potassium and other plant nutrients and return them to the soil". "Benefits of Grazing Cattle on the Prairie". Native Habitat Organization. Retrieved 1 Dec 2008 Grazing can reduce the accumulation of litter (organic matter) in some seasons and areas, but can also increase it, which may help to combat soil erosion. Dalrymple, R.L.. "Fringe Benefits of Rotational Stocking". Intensive Grazing Benefits. Noble Foundation. Retrieved 1 Dec 2008 This acts as nutrition for insects and organisms found within the soil. These organisms "aid in carbon sequestration and water filtration".
When grass is grazed, dead grass and litter are reduced, which is advantageous for birds such as waterfowl. Grazing can increase biodiversity. Without grazing, many of the same grasses grow, for example Bromus and Poa, consequently producing a monoculture. The ecosystems of North American tallgrass prairies are controlled to a large extent by nitrogen availability, which is itself controlled by interactions between fires and grazing by large herbivores. Fires in spring enhance the growth of certain grasses. Herbivores preferentially graze these grasses, producing a system of checks and balances, and allowing higher plant biodiversity. In Europe heathland is a cultural landscape which requires grazing by cattle, sheep or other grazers to be maintained.
Much grazing land has resulted from a process of clearance or drainage of other habitats such as woodland or wetland.
According to the opinion of the Center for Biological Diversity, extensive grazing of livestock in the arid lands of the southwestern United States has many negative impacts on the local biodiversity there.Center for Biological Diversity|source= Grazing
In arid climates such as the southwestern United States, livestock grazing has severely degraded riparian areas, the wetland environment adjacent to rivers or streams. The Environmental Protection Agency states that agriculture has a greater impact on stream and river contamination than any other nonpoint source. Improper grazing of riparian areas can contribute to nonpoint source pollution of riparian areas. Riparian zones in arid and semiarid environments have been called biodiversity hotspots. The water, higher biomass, favorable microclimate and periodic flood events together produce higher biological diversity than in the surrounding uplands. In 1990, "according to the Arizona state park department, over 90% of the original riparian zones of Arizona and New Mexico are gone". A 1988 report of the Government Accountability Office estimated that 90% of the 5,300 miles of riparian habitat managed by the Bureau of Land Management in Colorado was in an unsatisfactory condition, as was 80% of Idaho's riparian zones, concluding that "poorly managed livestock grazing is the major cause of degraded riparian habitat on federal rangelands".
A 2013 FAO report estimated livestock were responsible for 14.5% of anthropogenic greenhouse gas emissions. Grazing is common in New Zealand; in 2004, methane and nitrous oxide from agriculture made up somewhat less than half of New Zealand's greenhouse gas emissions, of which most is attributable to livestock. A 2008 United States Environmental Protection Agency report on emissions found agriculture was responsible for 6% of total United States greenhouse gas emissions in 2006. This included rice production, enteric fermentation in domestic livestock, livestock manure management, and agricultural soil management, but omitted some things that might be attributable to agriculture. Studies comparing the methane emissions from grazing and feedlot cattle concluded that grass-fed cattle produce much more methane than grain-fed cattle. One study in the Journal of Animal Science found four times as much, and stated: "these measurements clearly document higher CH4 production for cattle receiving low-quality, high-fiber diets than for cattle fed high-grain diets".
Conservation
An author of the Food and Agriculture Organization (FAO) report Livestock's Long Shadow, stated in an interview:
Agrivoltaics
Agrivoltaics for grazing would allow for shade for the animals as well as the Vegetation so the soil retains a higher moisture level. This approach not only reduces maintenance costs by minimizing the need for mechanical mowing but also enhances land productivity by integrating renewable energy production with agricultural use.
See also
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