4
of the workforce (Qushimov et al. 2007). Currently, agriculture remains an important sector in the economy of Central Asia, providing 5.2% of the GDP in Kazakhstan,
7.5% in Turkmenistan, 18.5% in Uzbekistan, 20.8% in Kyrgyzstan, and 23.3% in
Tajikistan (Hamidov et al. 2016). Consequently, a better understanding of the impact
of climate change on soil erosion is also essential to improve the economy of
Central Asia.
Along with the atmosphere and hydrosphere, the soil cover (pedosphere) is also
subjected to negative anthropogenic influences (Denisov 2006; Shigaeva 2008). The
protection of soils and their rational use are of primary importance for the financial
and social growth of the country. The significance of the current state of soil
resources, their judicious use, and their careful treatment help improve their fertility.
Soil erosion is adapted to the biophysical environment, including soil, sediments,
topography, land cover, and interactions between them.
The major features of terrains affecting the mechanism of soil loss are slope
length, shape, and appearance. The impact of slope and aspect plays a significant
role in the flow mechanism. The higher the slope, the higher the runoff, and the
more infiltration is decreased. The drain formed on the slope finds a path nearby,
which causes soil erosion as the flow rate increases.
Due to erosion occurring over the past 40 years, 30% of the arable land worldwide has become unproductive (Jahun et al. 2015). Erosion occurs when the soil
remains exposed to rain or wind energy, so raindrops with high energy hit the open
soil and easily remove soil particles from the surface. The impact intensifies on
sloping areas, where often more than half of the soil surface is carried away as water
flows along valleys and waterways (Jahun et al. 2015). Thus, the rate of erosion is
influenced by soil composition, land slope, and vegetation cover. The problem of
population growth is the increased demand for food and arable land. As a result,
forest, soil, and water resources are exploited wastefully. Soil erosion also causes
off-site damage, such as river sediment deposition, reservoir sedimentation, and
canal siltation. Damages can lead to significant economic losses (Li and Fang 2016).
Soil structure influences the ease with which it can be eroded. Soils with medium
to fine texture, low organic matter content, and weak structural development are
easily eroded. The erodibility of soil depends on its texture and structure, organic
matter content, and permeability (Wischmeier and Smith 1978). Soil erodibility
refers to the susceptibility of the soil to erosion. At a general level, this depends
primarily on the structural stability of the soil and its ability to absorb rainfall.
The topography of a given landscape, its rainfall, and wind all combine to influence
its susceptibility to erosion. Topography is undoubtedly one of the most critical determinants of soil erosion. Typically, erosion only becomes severe when the slope angle
exceeds a critical steepness and then subsequently increases logarithmically. Runoff
and erosion also tend to increase with the increase in slope length. The effect of topography also often occurs at a mostly local level, with erosion being initiated in specific
locations on the slope, or in association with minor topographic variations.
In practical terms, the vegetation cover is possibly the most crucial element in the
hillslope erosion model, since it is the factor that can be readily altered. Moreover,
it provides the first opportunity for soil erosion control (Briggs et al. 1992). Land
areas covered by plant biomass are more protected and experience relatively little
1 Introduction and Background of Rainfall Erosivity Processes and Soil Erosion
of the workforce (Qushimov et al. 2007). Currently, agriculture remains an important sector in the economy of Central Asia, providing 5.2% of the GDP in Kazakhstan,
7.5% in Turkmenistan, 18.5% in Uzbekistan, 20.8% in Kyrgyzstan, and 23.3% in
Tajikistan (Hamidov et al. 2016). Consequently, a better understanding of the impact
of climate change on soil erosion is also essential to improve the economy of
Central Asia.
Along with the atmosphere and hydrosphere, the soil cover (pedosphere) is also
subjected to negative anthropogenic influences (Denisov 2006; Shigaeva 2008). The
protection of soils and their rational use are of primary importance for the financial
and social growth of the country. The significance of the current state of soil
resources, their judicious use, and their careful treatment help improve their fertility.
Soil erosion is adapted to the biophysical environment, including soil, sediments,
topography, land cover, and interactions between them.
The major features of terrains affecting the mechanism of soil loss are slope
length, shape, and appearance. The impact of slope and aspect plays a significant
role in the flow mechanism. The higher the slope, the higher the runoff, and the
more infiltration is decreased. The drain formed on the slope finds a path nearby,
which causes soil erosion as the flow rate increases.
Due to erosion occurring over the past 40 years, 30% of the arable land worldwide has become unproductive (Jahun et al. 2015). Erosion occurs when the soil
remains exposed to rain or wind energy, so raindrops with high energy hit the open
soil and easily remove soil particles from the surface. The impact intensifies on
sloping areas, where often more than half of the soil surface is carried away as water
flows along valleys and waterways (Jahun et al. 2015). Thus, the rate of erosion is
influenced by soil composition, land slope, and vegetation cover. The problem of
population growth is the increased demand for food and arable land. As a result,
forest, soil, and water resources are exploited wastefully. Soil erosion also causes
off-site damage, such as river sediment deposition, reservoir sedimentation, and
canal siltation. Damages can lead to significant economic losses (Li and Fang 2016).
Soil structure influences the ease with which it can be eroded. Soils with medium
to fine texture, low organic matter content, and weak structural development are
easily eroded. The erodibility of soil depends on its texture and structure, organic
matter content, and permeability (Wischmeier and Smith 1978). Soil erodibility
refers to the susceptibility of the soil to erosion. At a general level, this depends
primarily on the structural stability of the soil and its ability to absorb rainfall.
The topography of a given landscape, its rainfall, and wind all combine to influence
its susceptibility to erosion. Topography is undoubtedly one of the most critical determinants of soil erosion. Typically, erosion only becomes severe when the slope angle
exceeds a critical steepness and then subsequently increases logarithmically. Runoff
and erosion also tend to increase with the increase in slope length. The effect of topography also often occurs at a mostly local level, with erosion being initiated in specific
locations on the slope, or in association with minor topographic variations.
In practical terms, the vegetation cover is possibly the most crucial element in the
hillslope erosion model, since it is the factor that can be readily altered. Moreover,
it provides the first opportunity for soil erosion control (Briggs et al. 1992). Land
areas covered by plant biomass are more protected and experience relatively little
1 Introduction and Background of Rainfall Erosivity Processes and Soil Erosion