Lei Jiaqiang

Ecological stability of Tarim Desert Highway shelterbelt

The Tarim Desert Highway shelterbelt, located in hinterland of Taklimakan Desert, is irrigated by underground saline water, with three to thirty gram per litter mineral degrees. The sustainability and stability are affected by multifarious stress. The structural and functional characteristics of shelterbelt are studied to probe into correlation between environment and shelterbelt. On basis, decision analysis is applied to study ecological stability of the Tarim Desert Highway shelterbelt, to screen out limited factors, to establish general index system, and to evaluate the stability of the shelterbelt nowadays. Finally, the concept of ecological stability is utilized to manage the artificial ecosystem. The results show that the artificial ecosystem is relatively flimsy, whose stability can be increased by adjusting stand structure and improving the nutrient cycle.

Effect of Drip Irrigation Water with Different Salinity on Soil Microbe of the Tarim Desert Highway Shelter-Forest

Soil microbes in forest land are crucial to soil development and the production of available nutrients for forest trees in extreme arid areas. In this study, we used FAME and PCR-DGGE to study the effects of saline waters for drip irrigation on soil microbes in the shelter-belt along the Tarim Desert Highway in Northwest China. The main results revealed that differences in the soil microbial amounts, fatty acids and DNA segments among the shelter-belt lands drip-irrigated with different salinity waters were significant, and that the soil microbial amounts, diversities of fatty acid and DNA segments decreased with increasing water mineralization. Investigation of vertical differences in the soil microbial amount and fatty acid composition revealed that the maximum appeared at 5-30 cm, while the minimum was observed in the surface layer. The effects of the soil physical properties on the soil microbes were more notable than those of the nutrient contents. The salt composition form was dominated by Na+-Cl--SO42-, and the content of the SO42- was enhanced with increasing water mineralization. In conclusion, a high degree of mineralization of drip-irrigation water may cause the soil to harden and its quality to degrade gradually, which hinders the growth and development of forest soil microbes.

Change in soil physical and chemical property in the Tarim Desert Highway shelterbelt under saline water drip-irrigation.

Abstract The physical and chemical properties of drip-irrigated aeolian soil with highly saline groundwater in the shelterbelt along the Tarim Desert Highway were investigated. The results show that surface layer litter quantity increases with shelterbelt age. Soil compactness in crust, 0~5 cm, 5~15 cm and 15~30 cm soil layers also decreases with shelterbelt age. Soil organic matter content increases with the shelterbelt age, and on the other hand, gradually reduces from the top to deeper layer of the soil profile. Total salt content decreases with both shelterbelt age and soil depth. Individual ions content in crust layer decreases, that in 0~5 cm, 5~15 cm and 15~30 cm soil layers increases with shelterbelt age. Soil pH in crust, 5~15 cm and 15~30 cm layers decreases with shelterbelt age, while that in 0~5 cm soil layer increases with shelterbelt age. Key words Saline water drip-irrigation, Aeolian soil, Soil physical and chemical property, Tarim, Highway shelterbelt in desert, Taklimakan Desert (Received June 20, 2008; accepted Nov. 17, 2008)