Agriculture Reference
In-Depth Information
remaining 40% would be lost over the next 60 years at an average annual
rate that is less than half of the average soil carbon decay rate over the fi rst
40 years. The integrated annual GHG emissions over the payback period
can be compared to the change in soil carbon stock over that period. A
payback period that is appreciably shorter than the 40 year decay period
represents a net gain in GHG mitigation potential.
6.2.3 THE BEEF TO PORK REDISTRIBUTION
To demonstrate the inter-commodity interactions, a potential expansion
of the pork industry was assumed which would displace some of the beef
industry in Canada. Whereas beef cattle in Canada are raised mainly on
roughages supplemented by grain, hogs are completely dependent on an-
nual crops. Therefore, additional feed grain area would be required for
the expanded hog population. This livestock redistribution illustrates the
tradeoff between the reduction of enteric methane emissions and the soil
carbon loss during the replacement of perennial forage cover with annual
crops. Related changes in the LCC will include more fossil fuel use for
farm field operations and an increase in N
2
O emissions due to higher ni-
trogen fertilizer requirements.
The quantitative basis of the beef to pork redistribution test was to
avoid any loss of protein supply. Hence, the increase in pork production
must supply the same amount of protein as was lost from beef produc-
tion. The two quantities of protein were calculated using the protein to
live weight conversion factors from Dyer et al. [41]. The beef and pork
systems have different intensities based on protein production [41], These
differences in GHG emission intensities can also be seen in beef and
pork comparisons based on live weight production [4,42-44]. However,
it was not the objective of this paper to compare productivities of these
industries, but to ensure that the loss in food production from the land use
change would be minimized.
Because the BCC can include land that is typically only suitable for
growing perennial forages [45], only a portion of the BCC can be real-
located to grow annual crops in the PCC to feed hogs. As recognized by
Basarab et al. [44], the chance of some of that redistributed land being
