Agriculture Reference
In-Depth Information
Increasing Terrestrial
C Pool in the
Biosphere
Soil Carbon
Forest Carbon
Wetlands
Biofuels
Organic Carbon
Biomass
Carbon
Woody
Perennials
Aboveground
Biomass and the
Detritus Material
Inorganic
Carbon
Perennial
Grasses
Belowground
Biomass
Soil Carbon
Depth
Distribution
Stable humic
substances
Liable pool
Dissolved
organic/inorganic
components
Recalcitrant
Compounds
(e.g., Lignin,
Seubrin,
Phenols)
Increase in Net Ecosystem Productivity
fIguRe 18.3
Strategies of enhancing carbon pool in the biosphere. NPP, net primary
productivity.
tion of the TCP. Wetlands constitute a minor but an important component of the TCP,
in terms of both the biomass and the soils' carbon.
Biofuels and their use are important to stabilization of the atmospheric abun-
dance of CO
2
and are discussed in another section. Sources of biofuel feedstock,
crop residues versus energy plantations, can have a significant impact on the SOC
pool and TCP. Removal of crop residues as a source of lignocellulosic biomass for
bioethanol production can have an adverse impact on soil quality and exacerbate soil
erosion and physical degradation.
Several mechanisms of soil carbon sequestration (e.g., physical, chemical, bio-
chemical) protect the SOM pool against microbial attack. The SOM pool is also
protected from climatic and anthropogenic perturbations by translocation (illuvia-
tion, or vertical movement) into the subsoil and deposition/burial (lateral movement)
into depressional sites (Figure 18.4). These protective mechanisms, while increasing
the residence time of carbon in soil, have numerous positive impacts on soil and
the environment. Improvements in soil quality lead to an increase in the net pri-
mary productivity, decrease in losses of water and nutrient, reduction in non-point
source pollution, and increase in biodiversity, especially that of the soil (Figure 18.4).
Increase in biomass input into the soil has numerous ancillary benefits and increases
ecosystem services.
