Agriculture Reference
In-Depth Information
Food versus feed for
humans and animals
Land use
Global animal agriculture occupies the largest
land mass of any human activity (Steinfeld
et al
.,
2006; Steinfeld and Wassenaar, 2007). As much
as 30% of the world's usable land is grazed, and
about a third of the cultivated area is used for ani-
mal feed and forage production (Asner
et al
.,
2004; Ramankutty
et al
., 2008). Little increase in
available pastureland is anticipated in the future
(Bruinsma, 2003; MA, 2005). However, some
intensification and effective management of
pasture-based production in sub-humid and
humid areas is expected. Effective management of
agriculture land in mixed plant-animal systems
potentially can be quite sustainable and efficient
if done appropriately in nutrient cycles (Shutt,
1913 as cited by Janzen, 2011). Improved utiliza-
tion of land by ruminants in semi-arid and arid
regions may be a potential option if managed
properly (e.g. Janzen, 2011; Savory Institute,
2012). Issues with land use and animal agricul-
ture can and do arise when excess nutrients from
animal systems contaminate other lands, waters
or ecosystems, or when the animals and land
base are separated too far from one another
for cost-effective recycling of nutrients among
soil, plants and animals. In the future, especially
more grazing systems likely will be positioned to
provide ecosystems services and goods that soci-
eties demand. Perhaps animal agriculture in
these situations also can be a benefit with trad-
able attributes (e.g. sheep or goats grazing
public-urban easements for vegetation control).
Especially in more developed countries, competi-
tion for land for biofuel production prompted
by concerns over energy insecurity, climate
change and alternative income sources likely will
diminish land use for animal agriculture.
However, it is noted that insufficient knowledge
about the opportunities, options and interrela-
tionships among food, feed and fuel in both
developed and developing countries currently
exist, especially with regard to coming second-
generation bioenergy technology (Van Vuuren
et al
., 2010). Additionally, destruction of Amazon
tropical forests (to make grazing land for live-
stock) has raised major concern (Herrero
et al
.,
2009; Barona
et al
., 2010) and desertification of
natural rangelands (Savory Institute, 2012) are
major ecological concerns resulting in loss of car-
bon storage capacity, habitat and biodiversity.
Recent estimates are that between 30% and
40% of cereal grains (food-feed crops) produced
worldwide are fed in animal agriculture (Garnett,
2009; Godfray
et al
., 2010). This could increase
to almost half of the total cereal production if
current trends continue (UNEP, 2009). In the
last half century or more, this rising grain pro-
duction occurred mainly in developed countries
with intensification of irrigation, relatively inex-
pensive (government-subsidized) fossil fuel prices
to grow cultivated crops, and government farm
subsidy programmes that stimulated crop pro-
duction with attractive profits for farmers (NRC,
2010). Consequently, with greater grain supplies
at relatively inexpensive prices, highly digestible/
utilizable cereal concentrates and some supple-
mental protein sources were abundantly avail-
able for livestock. This allowed much greater
animal growth and intensification of animal
agriculture in some regions (Gerber
et al
., 2010),
and diminished or disconnected interconnec-
tions among soil, plants and animals especially
crucial for effective nutrient cycling and healthy
soils (Naylor
et al
., 2005). Thus, more fertile
cropland that could be used to produce human
food produced feed for animals. Additionally, sig-
nificant quantities of food energy and nutrients
from highly digestible plant material were lost in
the relatively poor conversion to animal prod-
ucts. Therefore, the number of people who might
have been fed per unit of land presumably
declined compared with the possible scenario in
which humans consumed the cereals directly.
The United Nations Environment Programme
(UNEP) (2009) suggested that constraining
global meat consumption in 2050 to 2000 rates
would provide enough grain for 1.2 billion
humans. However, of course, making the grains
available for humans by reducing consumption
of meat does not guarantee that the grain would
become available as food for hungry people
somewhere else in the world (Stokstad, 2010).
Also, with reduced availability of land resources
(noted previously) whether or not continued
intensification and use of cultivated or cultivata-
ble land and water resources (also noted previ-
ously) can or should be used for production of
grain and high-quality protein feeds for animal
agriculture, doubtless will be a critical question
