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Bare
soil is prone to erosion and nutrient leaching. In regard to soil
carbon it
will always be lower than the same crop with vegetation due to the
carbon in
the above and below ground biomass. This can be reduced by using
"catch" and "cover" crops which will cover the soil in between the
actual crop or
in fallow
periods, respectively. (Barth's et al., 2004; Freibauer et al., 2004)
Emissions from drained organic soils can be reduced to some extent by
practices
such as avoiding row crops and tubers, avoiding deep ploughing, and
maintaining
a shallower water table. But the most important mitigation practice is
avoiding
the drainage of these soils in the first place or re-establishing a
high water
table (Freibauer et al., 2004).
A large proportion of agricultural lands has been degraded by excessive
disturbance, erosion, organic matter loss, salinisation, acidification,
or
other processes that curtail productivity (Batjes, 1999; Foley et al.,
2005;
Lal, 2001a, 2003, 2004b). Often, carbon storage in these soils can be
partly
restored by practices that reclaim productivity including:
re-vegetation (e.g.,
planting grasses); improving fertility by nutrient amendments; applying
organic
substrates such as manures, biosolids, and composts; reducing tillage
and
retaining crop residues; and conserving water (Lal, 2001b; 2004b; Bruce
et al.,
1999; Olsson and Ardo, 2002; Paustian et al., 2004).
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