Agriculture Reference
In-Depth Information
lowest g carbon-equivalent per-kg biomass emissions among corn (246-
286), soybeans (159-163) and switchgrass (124-147) compared with just
89 for alfalfa. Finishing beef cattle on high quality pastures can reduce
GHG emissions and the global warming potential (GWP) associated with
grass finished beef. This can occur through increased sequestration of CO
2
into soil organic carbon and/or through decreased emissions of N
2
O and
methane with their potent GWP [103,104]. Rangelands and pastures are
well-known for their ability to increase soil carbon stocks [105], and this
trait should differ little between non-organic and organic systems.
Beef cattle production conducted on rangeland generally requires a sig-
nifi cant amount of land, and therefore tends to be extensive and uncultivated
with intact natural biodiversity [106]. There are approximately 2 million
acres of certifi ed organic rangeland in the US [107], but little information
is available on the implications of management practices specifi c to certi-
fi ed organic rangeland, much of which is found in the western US. Because
chemical fertilization and weed control are usually not economically fea-
sible on non-organic rangeland, organic rangeland would not be expected to
differ greatly from non-organic. In a review by Sayre et al. [106], it was not-
ed that ranching conducted on rangelands exemplifi es many of the defi ning
characteristics of diversifi ed farming systems, as it relies on the functional
diversity of natural processes of both plants and animals and creates services
generated and regenerated locally without nonrenewable inputs.
4.6 ECONOMICS OF GRAZING-BASED CATTLE SYSTEMS
Feed is the greatest cost associated with milk and meat production [108].
Therefore, when grazed forage can replace the use of more expensive
grains or conserved forages it is possible to decrease the input costs of
ruminant production systems.
4.6.1 ECONOMICS OF DAIRY SYSTEMS
Many studies have conducted direct comparisons of pasture-based (but
not necessarily organic) and confinement dairy systems and have reported
