Agriculture Reference
In-Depth Information
N may be reintroduced or introduced into the
cycle by fertilization (e.g. from manure or com-
mercial synthetic fertilizer), by N-fixing plants,
or by deposition from the atmosphere.
In the past (e.g. in the USA - late
1800s-1940s), the cyclic flow of nutrients more
or less occurred typically in individual multi-
purpose farms without much notice or docu-
mentation. Virtually all of these farms were by
necessity mixed crop-animal systems. After the
Second World War, industrialization of agricul-
ture began to varying degrees in different
regions. This began to change the mixed plant-
animal system paradigm. Whereas many of
these so-called 'industrial farms' could excel at
increasing productivity and efficiency and were
increasingly significant contributors to the food
supply at relatively inexpensive food prices,
nutrients (e.g. feed and fertilizer nutrients) trav-
elled to these farms from farther away distances,
and nutrient cycles occupied larger land areas as
some farms became more specialized and con-
centrated their human and financial capital in
more specialized and intensive farming opera-
tions. Many farms concentrated efforts and
investments almost entirely in either crop farm-
ing or animal farming. This necessitated a need
for feed crops, ration supplements (e.g. speciality
ingredients with denser concentrations of
high-quality protein, minerals and vitamins).
Consequently, nutrients were transported long
distances (at least partially because of relatively
inexpensive, government-subsidized fossil fuels)
to these specialized animal farms (Naylor
et al
.,
2005). This resulted in the greater concentration
of nutrients and animals in smaller, finite land
spaces. Eventually, some areas predominated for
crop production, whereas others focused more
on animal production. With this shift the once
cyclic flow of nutrients among the soil, and crop
and animal enterprises within some single farm
(sub-) systems was at risk of becoming discon-
nected or even truncated (Naylor
et al
., 2005).
As a consequence, nutrients (e.g. P, N, K)
moved from crop-producing areas to some
animal-producing areas, but were not effectively
recycled within the (sub-) system or moved back
to their origin; thus, in some cases they accumu-
lated over time, and water and air pollution
problems arose (Chapters 7, 8, 9, 10 and 11).
Consequently, these nutrients were accumulat-
ing in regions where animal agriculture was
predominant without enough space or plants to
complete the cycles for healthy soil building to
fortify soil tilth. Also, some crop-producing areas
became depleted of needed nutrients, or appreci-
able application of synthetic fertilizers replaced
the nutrients from animal manure that previ-
ously were recycled to cropland.
Now federal and state regulations (e.g. US
Clean Water and Clean Air Acts), largely conse-
quences of breaking nutrient cycles in individ-
ual farm (sub-) systems or aggregate farm
systems, have been implemented to hold farms
(especially large farms) accountable for effective
management of manure nutrients and to avoid
over-application and leakage of nutrients
(e.g. Chapters 7, 8, 9 and 10). Compliance with
regulation increased and continues to increase,
making export of manure nutrients necessary
when local land base is insufficient for proper
application of nutrients, installation of new
technologies to deal with excess nutrients,
implementation of mitigation techniques, or in
some cases depopulation from livestock farms in
nutrient-dense regions. All of these additional
management practices impose exorbitant costs
in the short- and medium-terms on farmers,
agriculture in general, rural communities in the
affected regions, and ultimately on society. Much
of this could have been and can be avoided if the
soil, plants and animals were kept in relatively
close and economic proximity. Many of these
additional costly practices are relatively tempo-
rary incremental short-gap fixes - export of
nutrients, mitigation techniques and depopula-
tion - that must give way to a much larger trans-
formation in the future (see subsequently).
Potential Benefits of
Animal Agriculture
Animal agriculture in very extensive to very
intensive production systems potentially has at
least three significant attributes beneficial to
humankind. First, and most obviously, animals
provide food, fibre, livelihoods, prosperity and
enjoyment for humankind. It also is known that
as wealth and standard of living increase in
many societies people's diets are comprised of
larger proportions of food derived directly from
animals (FAO, 2005; Steinfeld
et al
., 2006;
McMichael
et al
., 2007; Garnett, 2009, 2010).
