Climate Change and Dryland Agricultural Ecosystem Management

protection. As Heihe River is a typical inland river, this study could provide consultation for the
synthesized management of other inland rivers. At the same time, this study could make various
circles understand the actual process of ecological management in the upper reaches of Heihe River
objectively, and absorb the useful experience from this ecological project.
The upper reaches of Heihe River include two main administrative divisions which are Qilian county
in Qinghai Province and Sunan county in Gansu Province. In order to evaluate the ecological
environment effect in the upper reaches of Heihe River after ecological management, authors
investigated and surveyed the two counties on the spot in 2006. The following investigation situation
of two districts is introduced, respectively. Ecological management projects include enclosing
meadow land, enclosing natural forest, and afforestation. The research areas are selected in the Heihe
River mainstream and the upper and middle reaches of Liyuan River. Regarding above two region’s
investigation, this paper adopts field sampling and gauging on the spot. Although precision of this
method is not very high, field sampling and gauging on the spot can reflect objectively the influence
of 3 year’s ecology management on the upper reaches of Heihe River.
Enclosing natural forests and afforestation are effective measures to conserve water and soil. The
function of water conservation and reducing sand displays in two aspects. Firstly, projects of
afforestation and land preparation change the partial terrain, reduce the soil erosion amount. Secondly,
all kinds of vegetation covering the land surface reduces or avoids the rainwater’s erosion to soil, and
then strengthens the ability of the soil-anti-infiltration. Simultaneously, it reduces the silt of
downstream reservoir, saves massive labor forces and the funds, and also reduces the flood harm to
the middle and lower reaches river. The implementation of enclosing natural forests and afforestation
can prohibit the humanity from cutting down the trees and the domestic animals gnawing sapling,
which is advantageous to the natural forests’ growth and the renewal. Moreover, because enclosing
natural forests and afforestation can restore the forest vegetation, it will increase the humus content of
soil surface layer, enhance the soil fertility, and is advantageous to the vegetation's growth with
deadwood and fallen leaf accumulating rottenly. Simultaneously, the forest has the function of
controlling the runoff, so it will weaken the flood harm. Moreover, the increase of forest coverage rate
improves the habitat environment for the wild animal and is advantageous to wild animal's growth and
breeding.
Lawn land is the material basis concerning the survival and development of herdsman. The sustainable
utilization of pastures is one of basic essential factors for the economy development of pastoral area,
and the herdsman’s prosperous life. Enclosing the lawn land can reduces the domestic animal’s
excessive gnawing and tramples to the forage grass. Enclosing the lawn land and prohibiting grazing
enable the lawn to obtain the reasonable restoration, vegetation degree of coverage to increase lawn.
The ecological management project has obtained remarkable ecology effect. Compared the pasture in
enclosure with the pasture outside enclosure, the yield of grass of pasture in enclosure has been
enhanced greatly. At the same time, the mean height, and degree of grass cover and so on. The
ecological management project has certain function to the restoration of the water conservation ability
in the upper reaches of Heihe River. The water conservation ability has strengthened unceasingly, so
the ecological environment has obtained the effective improvement.
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