Geoscience Reference
In-Depth Information
Hess et al., 2006; Kamra et al., 2006; Newbold and Rode, 2006;
Patra et al., 2006).
Long-term management changes and animal breeding:
Breeding for high-yielding varieties and better management
practices for improved efficiency (producing meat—animals
reach slaughter weight at a younger age) and decreasing
replacement heifers reduces methane emission per unit of ani-
mal product (Lovett and O'Mara, 2002; Boadi et al., 2004;
Kebreab et al., 2006; Lovett et al., 2006).
Manure
management
CH
4
or N
2
O emissions from stored manure can be reduced by
cooling, use of solid covers, mechanically separating solids
from slurry, composting (solidifying), anaerobical digestion to
capture CH
4
for renewable energy source or by altering feeding
practices (Amon et al., 2001; Clemens and Ahlgrimm, 2001;
Gonzalez-Avalos and Ruiz-Suarez, 2001; Monteny et al., 2001,
2006; Külling et al., 2003; Paustian et al., 2004; Chadwick,
2005; Pattey et al., 2005; Amon et al., 2006; Clemens et al.,
2006; Hindrichsen et al., 2006; Kreuzer and Hindrichsen,
2006; Xu et al., 2007). However, globally for most animals
there is limited opportunity for manure management, treatment
or storage as excretion happens in the field, and handling for
fuel or fertility amendments occur when it is dry and methane
emissions are negligible.
Bio energy
Facing pollution threats from fossil fuels, forest/agricultural
crops and residues are now being increasingly used as green
fuel for a viable alternative (Rogner et al., 2000; Cerri et al.,
2004; Edmonds, 2004; Hamelinck et al., 2004; Hoogwijk,
2004; Paustian et al., 2004; Richter, 2004; Sheehan et al., 2004;
Dias de Oliveira et al., 2005; Eidman, 2005; Hoogwijk et al.,
2005; Anonymous, 2006e; Faaij, 2006). Biofuels also release
CO
2
but this CO
2
is of recent atmospheric origin, which dis-
places CO
2
released from fossil carbon. The net benefit to atmo-
spheric CO
2
, however, depends on energy used in growing and
processing the bioenergy feedstock (Spatari et al., 2005).
Some mitigation measures operate predominantly on one
GHG (e.g. dietary management of ruminants to reduce CH
4
emissions) while others have impacts on more than one GHG
(e.g. rice management). Moreover, practices may benefit more
than one gas while others involve a trade-off between gases
(e.g. restoration of organic soils). Consequently, a practice that
is highly effective in reducing emissions at one site may be less
effective or even counterproductive elsewhere. This means that
there is no universally applicable list of mitigation practices and
