ANIMAL FORUM

On Sat, 24 Feb 2007 18:33:34 -0000, pearl wrote:


Environmental Benefits

Well-managed perennial pastures have several environmental
advantages over tilled land: they dramatically decrease soil
erosion potential. require minimal pesticides and fertilizers,
and decrease the amount of barnyard runoff.

Data from the Soil Conservation Service shows that in 1990, an
average of 4.8 tons of soil per acre was lost to erosion on
Wisconsin cropland and an average of 2.6 tons of soil per acre
was lost on Minnesota cropland. Converting erosion-prone land to
pasture is a good way to minimize this loss since perennial
pastures have an average soil loss of only 0.8 tons per acre. It
also helps in complying with the nationwide T by 2000 legislation
whose goal is that erosion rates on all fields not exceed tolerable
limits (T) by the year 2000. Decreasing erosion rates will preserve
the most fertile soil with higher water holding capacity for future
crop production. It will also protect our water quality.

High levels of nitrates and pesticides in our ground and surface waters
can cause human, livestock, and wildlife health problems. Pasturing has
several water quality advantages. It reduces the amount of nitrates and
pesticides which leach into our ground water and contaminate surface
waters. It also can reduce barnyard runoff which may destroy fish and
wildlife habitat by enriching surface waters with nitrogen and
phosphorous which promotes excessive aquatic plant growth (leading to
low oxygen levels in the water which suffocates most water life).

Wildlife Advantages

Many native grassland birds, such as upland sandpipers, bobolinks, and
meadowlarks, have experienced significant population declines within
the past 50 years. Natural inhabitants of the prairie, these birds
thrived in the extensive pastures which covered the state in the early
1900s. With the increased conversion of pasture to row crops and
frequently-mowed hay fields, their habitat is being disturbed and their
populations are now at risk.

Rotational grazing systems have the potential to reverse this decline
because the rested paddocks can provide undisturbed nesting habitat.
(However, converting existing under-grazed pasture into an intensive
rotational system where forage is used more efficiently may be
detrimental to wildlife.) Warm-season grass paddocks which arent grazed
until late June provide especially good nesting habitat. Game birds, such
as pheasants, wild turkey, and quail also benefit from pastures, as do
bluebirds whose favorite nesting sites are fenceposts. The wildlife
benefits of rotational grazing will be greatest in those instances where
cropland is converted to pasture since grassland, despite being grazed,
provides greater nesting opportunity than cropland.

Pesticides can be very damaging to wildlife. though often short lived in
the environment, some insecticides are toxic to birds and mammals
(including humans). Not only do they kill the target pest but many kill a
wide range of insects, including predatory insects that could help prevent
future pest out breaks. Insecticides in surface waters may kill aquatic
invertebrates (food for fish, shorebirds, and water fowl.) Herbicides can
also be toxic to animals and may stunt or kill non-target vegetation which
may serve as wildlife habitat.

http://www.forages.css.orst.edu/Topics/Pastures/Grazing/Systems/Techniques/MIG/Why.html
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wrote in message news:2qf3u29immv1543lctorpsjc9vaoi6cptd@4ax.com...

Livestock a major threat to environment
..
... a steep environmental price, according to the FAO report,
Livestocks Long Shadow -Environmental Issues and Options.
The environmental costs per unit of livestock production must
be cut by one half, just to avoid the level of damage worsening
beyond its present level, it warns.

When emissions from land use and land use change are included, the
livestock sector accounts for 9 percent of CO2 deriving from human-
related activities, but produces a much larger share of even more
harmful greenhouse gases. It generates 65 percent of human-related
nitrous oxide, which has 296 times the Global Warming Potential
(GWP) of CO2. Most of this comes from manure.

And it accounts for respectively 37 percent of all human-induced
methane (23 times as warming as CO2), which is largely produced
by the digestive system of ruminants, and 64 percent of ammonia,
which contributes significantly to acid rain.

Livestock now use 30 percent of the earths entire land surface, mostly
permanent pasture but also including 33 percent of the global arable
land used to producing feed for livestock, the report notes. As forests
are cleared to create new pastures, it is a major driver of deforestation,
especially in Latin America where, for example, some 70 percent of
former forests in the Amazon have been turned over to grazing.

Land and water

At the same time herds cause wide-scale land degradation, with about
20 percent of pastures considered as degraded through overgrazing,
compaction and erosion. This figure is even higher in the drylands
where inappropriate policies and inadequate livestock management
contribute to advancing desertification.

The livestock business is among the most damaging sectors to the
earths increasingly scarce water resources, contributing among other
things to water pollution, euthropication and the degeneration of coral
reefs. The major polluting agents are animal wastes, antibiotics and
hormones, chemicals from tanneries, fertilizers and the pesticides used
to spray feed crops. Widespread overgrazing disturbs water cycles,
reducing replenishment of above and below ground water resources.
Significant amounts of water are withdrawn for the production of feed.

Livestock are estimated to be the main inland source of phosphorous
and nitrogen contamination of the South China Sea, contributing to
biodiversity loss in marine ecosystems.

Meat and dairy animals now account for about 20 percent of all
terrestrial animal biomass. Livestocks presence in vast tracts of land
and its demand for feed crops also contribute to biodiversity loss; 15
out of 24 important ecosystem services are assessed as in decline,
with livestock identified as a culprit.
...
http://www.fao.org/newsroom/en/news/2006/1000448/index.html

Impact of livestock grazing on habitat and native wildlife worldwide:
http://www.wasteofthewest.com/Chapter6.html

...