Agriculture Reference
In-Depth Information
Table 3.2. Efficiency gains and trade-offs from cropping system changes.
a
Change in Cropping System
Change in Global
Warming Impact
(Mg CO
2
e ha
−1
yr
−1
)
Change in Profitability
($ ha
−1
yr
−1
)
Efficiency gains
Conventional to No-till
-1.00
45
Conventional to Reduced Input
-0.51
31
Reduced Input to No-till
-0.49
14
Alfalfa to Poplar
-0.85
93
Trade-offs along efficient frontier
No-till to Poplar
-1.19
-166
Biologically Based to Poplar
-1.46
-279
a
Based on MCSE systems assuming nonorganic grain prices. Changes in GWI and profitability represent mean
outcomes. Negative GWI indicates greenhouse gas mitigation, a positive outcome.
Source:
Profitability data for 1993-2007 adapted and updated from Jolejole (2009). Global warming impact (GWI)
data for 1991-1999 from Robertson et al. (2000).
The second important finding is the very high implied marginal cost per met-
ric ton of reducing GWI by moving along each of the efficient frontiers. The
marginal cost is the amount of crop net income given up per metric ton of GWI
gain by moving from one efficient system to another along the efficient fron-
tier. Arithmetically, it is the change in revenue above selected costs divided by
the corresponding change in GWI. The dashed line between Poplar and No-till
shows that the implied cost of reducing GWI by shifting land from the No-till
corn-soybean-wheat rotation to Poplar is $140 Mg
−1
CO
2
e ha
−1
yr
−1
. As illus-
trated by the solid line from Poplar to Biologically Based, the higher value of
certified organic production raises the unit cost of reducing global warming by
switching between these systems to $191 Mg
−1
CO
2
e ha
−1
yr
−1
. These implied
costs exceed the traded prices of carbon credits on international exchanges in the
early 2000s by an order of magnitude. The implication is that other methods can
abate CO
2
e emissions at far lower cost (e.g., improving efficiency of coal-fired
power plants or reducing N fertilizer use). Indeed, if substantial cropland were
shifted out of grain crops into poplar, market prices of grain crops would rise
and those of poplar would fall, making the implied marginal cost of shifting even
greater than shown here.
Supply of Crop Land to Boost Ecosystem Service Provision:
Application of Stated Preferences to Capture Farm Heterogeneity
Commercial farm conditions vary in terms of land quality, equipment avail-
ability, managerial ability, and farmer attitudes. Ecological experiments like
the MCSE intentionally hold all these factors constant, limiting the scope of
outcomes that can be explored in a trade-off analysis of experimental results.
Farmers, however, vary in their resources, priorities, and perceptions of the costs
