|其他摘要||Desert-oasis ecotone is import and sensitive fragile in arid region. The ecotone between the oasis and desert is not only the protective barriers of oases, but also maintain the sustainable development and the internal stability of oasis. Since 21th century, Desert-oasis ecotone in natural vegetation as the main ecosystems and ecological processes have been serious damaged, and “green corridor” is in dangerous. So estabilish the ecological restration demonstration and evaluate the comprehensive benefit of different vegetation restration patterns, which is in order to provide theoretical guidance for the establishment of ecotone ecological protection area and efficient economy.
The study which is based on the desert-oasis ecotone ecological resroration demonstration used the methods of “space instead of time” and experimental studies. The structure, stability of community, ecological processes (soil fertility, soil environment) as well as other economic indicators were measured and compared to evaluate the overall efficiency under different vegetation restoration patterns and different restoration years. The main conclusion are as follows:
1. After half of the year artificial water intervention ecological recovery, the vegetation cover increased and the species increased from 7 to 11. Because of replenishment, the soil seed bank was activated, Salsola year herd bloomed. Community has been optimized. Biodiversity index showed community stability increased and community succession trend is positive. However, because of the extrement arid environment, ecosystems still need human intervention and take long time to reach steady state.
2. Ecological restoration improved the soil environment significantly. Vegetation restoration improved soil moisture conditions effectively, soil water content of different vegetation restoration patterns in addition to the outer surface soil (0-5cm) was significantly higher than the previous ecological restoration. Soil water retention began to show from the layer of 15cm, in which 3 years Jujube recovery pattern has the best soil moisture condition. Soil pH value was between 7.91~ 8.72, and soil was alkaline in nature. Salsola, Lycium ruthenicum and Jujube are all salinity or salt-secreting plant for desalination of saline, which significantly reduced tatal salt content in the upper layer soil (0-30cm). And 50cm soil layer following changes were not significant.
3. Ecological restoration significantly improved soil fertility statue. Except total K other nutrition indexes showed obvious surface aggregation phenomenon, 50cm was a variation of differentiated layers. The soil nutrient index(SIN) of different vegetation restoration patterns displayed: 3 year Jujube (0.84)＞2 years Jujube (0.73)＞half of E. angustifolia (0.72)＞1 Lycium ruthenicum (0.69)＞4 year Jujube (0.61)＞before restoration (0.01). Vegetation restoration on soil nutrient improvement effect was remarkable. 3 year Jujube recovery pattern was most obvious on soil improvement, and 3 year Jujube recovery pattern was relatively worst, which may be related to plant biomass.
4. By calculating different vegetation restoration patterns of direct economic benefits (economic production-invest ratio, labor productivity and land production relation) and indirect economic benefits (maintain soil fertility value), results showed that: 3 year Jujube recovery pattern has the highest economic production-invest ratio, which showed an increasing trend with the restoration years increased. It indicted that the capital utilization efficiency and economic are increasing with the increase of the recovery period. Because of Lycium ruthenicum market rising price, 1 Lycium ruthenicum recovery pattern is of the highest labor productivity and land production relation. In addition to half of E. angustifolia recovery pattern, other vegetation recovery patterns all efficient used local light, heat, water and other natural resources. The soil fertility maintaining value of different vegetation restoration is : 2 years Jujube＞half of E. angustifolia＞3 year Jujube＞1 Lycium ruthenicum＞4 year Jujube. 2 year Jujube recovery pattern maintained maximum soil fertility value, up to 64957 yuan/hm2. Vegetation restoration based eco-restoration, effectively improved the soil fertility status and saved the land of fertilizer inputs.|