| 其他摘要 | The Loess Plateau is one of the most serious soil erosion regions in the world, where a
large number of manpower and material resources have been poured into soil and water
conservation management and research in the Loess Plateau, and make remarkable
achievements. At present, how to use a unified standard to evaluate and analyze regional
benefits of soil and water conservation has become a common issue for decision-makers
and researchers. With the support of RS and GIS technology, this paper analyzed dynamic
change of factors influencing benefits of soil and water conservation since the
implementation of "The Soil and Water Conservation and Ecological Protection Projects of
Yellow River in Tianshui City, Gansu Province ". This research applies ecosystem service
function value methods to evaluation and analysis some benefits of soil and water
conservation. The main conclusions are:
(1) Establishing Parameters for benefit evaluation of region-scale soil and water
conservation. Based on “national standard” and the principle of selecting indicators,
applying ecosystem service function value method, and taking root in the loess plateau,
this paper systematically analyzes the present research situation and problems of the
benefits evaluation of soil and water conservation. And then, the paper suggested a
regional-scale evaluation parameters system.
(2) Establishing the factors database of Jihe Demonstration Zone which influences
benefits of soil and water conservation. The database mainly consists of precipitation,
runoff , vegetation cover, land use, topography map, DEM, soil, thematic maps, remote
sensing image, field landscape pictures, and investigated data of practices of soil and water
conservation.
(3) Evaluating and analyzing the dynamic change of soil erosion. Based on the
Ministry of Water Resources criteria for soil erosion, the erosion lever of Jihe
Demonstration Zone mainly is moderate erosion. And the regional soil erosion decreased remarkably in 2005. Compared with 1997, the strength erosion, great strength erosion and
violent erosion were reduced by 10%, 10% and 4% respectively.
However, the evaluation based on the Regional Soil Erosion Model and the Chinese
Soil Loss Equation showed that the soil erosion lever of Jihe Demonstration Zone mainly
is micro and mildly erosion. Due to engineering practice factor, there is little variation of
soil erosion based on Chinese Soil Loss Equation. Meanwhile, based on the Regional Soil
Erosion Model, the soil erosion in 2005 was more intensive than it in 1997, due to the
rainfall intensity. Although the vegetation covered much in 2005 than in 1997, the soil
erosion caused by rainfall was far greater than the benefits of plants to reduce sediment,
which led to more serious soil erosion in 2005 than in 1997. This result is opposite to the
soil erosion evaluation of the Ministry of Water Resources. The reason is that the Ministry
of Water Resources of soil erosion standard does not take the effect of rainfall on soil
erosion into account.
(4)Investigating scale changes of NDVI. In this paper, a method is proposed to get
high spatial and temporal resolution NDVI products, by matching the histogram of ETM
NDVI (30 m) to that of SPOT/VEGETATION NDVI product (1 km, one scene every
month). The estimated NDVI products (30 m, one scene per month) are analyzed, based on
several indicators such as statistical characteristics of image, histogram similarity and
image fidelity. The results of this research can be applied to dynamic monitoring and
prediction of the region-scale soil erosion.
(5)Calculating the ecological value of different years in different state of soil and
water conservation based on GIS with the date of climate, soil, topography and land use
and obtained all the map of Jihe Demonstration Zone. This research chose one kind of
ecological service respectively from hydrosphere, soil sphere, biology sphere and
atmosphere to assess impacts of soil and water conservation on environment according to
the progress of ecological service research. |
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