Geoscience Reference
In-Depth Information
Climate effects: Guangxi is located in the subtropical climate with a long sunshine,
much heat and rainfall. The average rainfall is usually 1400 ~ 1800mm per year,
sometimes even more than 3000 mm. All these factors lead to serious soil loss,
especially in the heavy rain season, in which the erodible soil is strongly rinsed off and
only bare bedrocks remain;
The impact of geological conditions: the southeast of Guangxi is granite collapse Kong
area, and the northwest region is limestone area. Both of these two types of geological
rocks are more prone to form RD or potential RD areas;
Vegetation influence: Rare vegetation cover is an important factor to result in soil
erosion and form RD (see Fig. 9 and Fig. 10);
Topography effects: Soil erosion may also be accelerated by hilly and flat ground, steep
slope, broken terrain and cutting deep ravines in western Guangxi (Wei, 2002).
On the other hand, direct human activities possibly cause RD or potential RD areas in the
following ways:
Excessive deforestation makes the RD area enlarge seriously;
Human activities of production and life have an inextricably relationship with RD. The
impact of anthropogenic factors is always through various forms. Along with the rapid
growth of population, land and energy demand is increasing. This makes the original
forest resource dissipated very quickly. Moreover, the inappropriate farming methods,
such as the cultivation in high slope land, overgrazing, even excessive exploitation, as
well as the quick exploration of local small mines, road building projects, and other
industrial projects, make the ecological Karst areas brittle and weak, and showing a
rapid trend of RD (Li et al., 2006).
The prevention and control measures of RD from the natural factors can be carried out by
the following ways (Luo, 2007):
Water storage construction. Water storage project is an effective way to control RD
extending. This can reduce the seepage of rainwater, then reduce the soil erosion, and
can also satisfy the industrial and agricultural water demand as much as possible;
Forest planting. Making full use of solar thermal and water resources in the small gap
of the Karst land and planting more at these areas are both effective ways to reduce the
rock surface temperature and water consumption. They improve the micro-climate
conditions and slow down the rock desert process;
Development of three-dimensional ecological agriculture. In such extreme degradation
ecosystems of RD areas, the natural recovery of vegetation is very difficult. So it needs
biological, engineering and management measures by adjusting the irrigation system
and transformation of soil quality to improve soil fertility and improve the ecological
environment, in order to make the RD area back to normal.
There are also various means on prevention and control measures of RD from the human
activity factors, such as development of the biogas construction, population growth
controlling, industrial pollution prevention (Xu, 2006). In addition, it is effective to
propagate scientific knowledge on environment protection in the Karst area (Tang et al.,
2003). The obvious increase of good protected area and woodland from 2008 to 2010
indicates these propagation and prevention policies have produces positive results of
reducing RD in this area. However, there is still a long rough way to go for the public and
the government to bring the RD under control in western Guangxi of southwest China in
the future.
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