Agriculture Reference
In-Depth Information
and food-processing wastes (Garnett, 2009;
Bremer
et al
., 2010). Then the animal waste
can be recycled to soil; thus, creating an effi-
cient loop where the same nutrients can be
recycled over and over again, supplying
human-edible food in each turn of the cycle.
However, in the latter part of the 20th cen-
tury a notable (and well-publicized) portion of
animal agriculture followed a model more akin
to traditional industrial manufacturing, rather
than one built predominately to ensure effective
cyclic flow of nutrients and energy (Naylor
et al
.,
2005). For the most part, the industrial manu-
facturing process is not cyclic, but rather
essentially straight-line, in which products are
manufactured from raw materials into finished
products very efficiently with the aim of mini-
mal waste. In agriculture, the industrial model
afforded significant improvements in labour uti-
lization and land productivity during early
phases of use (after which soil health was jeop-
ardized and depleted), coupled with technologi-
cal advances, increasing the economic value of
agricultural products that could be realized. This
evolution was heavily influence by changing
markets and marketing systems (Chapter 12),
and at the same time in countries such as the
USA government-subsidized inputs (e.g. fossil
fuel) and crop commodity programmes favoura-
bly affected both input costs as well as output
revenue for some commodities (e.g. maize, soy-
bean, wheat, cotton), aiding and even catalysing
many animal farms to became more specialized,
increasing economic efficiency per animal and
per farm, and farm income (Hoshiba, 2002).
However, in contrast to the industrial
model, animal agriculture by its very nature
as a collection of biological processes is rela-
tively inefficient at transforming raw materials
(e.g. dietary nutrients) and energy into human-
desired products (Hoshiba, 2002; VandeHaar
and St-Pierre, 2006). Significant amounts of
unutilized nutrients (e.g. minerals, organics and
water) are generated during the transformation
processes of feed to animal products. For exam-
ple, the efficiency of dietary N capture in milk
ranges from 20% to 30% with the remainder
being excreted in manure (VandeHaar, 1998).
Animal production in some operations is
dependent upon large imports of feed grains
and supplements and, in many cases, forages
from local, regional farms, or even from crop-
producing areas considerable distances from
the animal farms. Under these circumstances,
resulting manure nutrients especially if still in
liquid form are not valued highly as a resource,
but rather as a waste product that must be man-
aged and ultimately disposed of (Chapters 7, 8
and 9). The once cyclic nature of nutrient utili-
zation and management characteristic of mixed
crop-animal farms to some extent gave way to a
much less efficient version of an industrial man-
ufacturing model with major waste disposal and
management challenges (Chapters 7, 8, 9 and 10).
The subsequent outcomes of industrial animal
agriculture led to numerous instances of envi-
ronmental problems without opportunity or
sufficient ability to manage nutrient cycles or
appropriate attentiveness to the general sustain-
ability of the overall food production system
(Hoshiba, 2002). This has resulted in consider-
able undesirable and unfavourable publicity espe-
cially for animal agriculture production systems.
There is a significant and sufficient body
of evidence indicating that integrating (mixing)
animals with plants provides much greater
opportunities to maintain sustainable agro-
ecosystems over time (e.g. Janzen, 2011). If
properly managed, the requisite nutrient cycles
can be sustainable; and especially important soil
tilth can be continuously improved and main-
tained, which is paramount to any agriculture
production system - especially, the sustainable
mixed plant-animal system.
Figure 18.3 conceptualizes how plant and
animal agriculture in both developing and
developed countries might move towards the
centre in a continuum of more sustainable
mixed plant-animal systems for 2050 and
beyond. The last section of this chapter addresses
the necessity of challenging primary issues and
paradigms, and capturing opportunities to cata-
lyse transformation from the very extensive and
from the excessively intensive farming systems
to evolve towards a continuum of sustainable
mixed plant-animal systems, of which animal
agriculture will be an indispensable component.
Transformation to sustainable
animal agriculture
Transformation of many sectors of animal
agriculture in developed and developing countries
