Agriculture Reference
In-Depth Information
Figure 2.5
. The increase in soil methanotroph diversity (open symbols) and atmospheric
methane consumption (closed symbols) in ecological succession from row-crop fields (Ag,
black) through early (dark gray) and mid-successional (medium grey) fields to mature forest
(light gray) at KBS LTER. Redrawn from Levine et al. (2011).
carbon storage but also reduced the CO
2
e costs of manufactured fertilizer nitrogen).
Designing optimal systems is not difficult; there are many practice-based opportu-
nities to diminish CO
2
e sources or enhance CO
2
e sinks and thereby help stabilize
the climate.
Providing Soil Fertility, the Basis for Sustained Crop Production
Closely tied to other services, such as food production and greenhouse gas mitiga-
tion, is soil fertility. As a supporting service that underpins the provision of other
services (MA 2005), soil fertility is under management control and is therefore a
deliverable service; in its absence, fertility must be enhanced with greater quan-
tities of external inputs, such as fertilizers, and the system is less able to with-
stand extreme events, such as drought. That said, soil fertility is not a panacea
for reducing the environmental impacts of agricultural systems; for example, N
2
O
production was as high in our Biologically Based system as it was in the less fertile
Conventional system (Robertson et al. 2000).
Soil fertility has many components. Physically, fertility is related to soil
structure—porosity, aggregate stability, water-holding capacity, and erosivity.
