干旱区生态环境知识资源中心

Dew is an important source of moisture for ecosystem in arid region. To understand the characteristics of dew deposition during growing season, micro-lysimeters and neutron probe were used to measure the amounts of dew and dew duration on different types of underlying surfaces (Populus euphratica forest, Tamarix bushes and bare land) in the lower reaches of the Tarim River, northwestern China. The results observed using micro-lysimeters and neutron probe showed that the maximum total dew amount occurred on the surface of bare land, while the minimum total dew amount was recorded on the surface of Populus euphratica forest. Dew amount of the connected treatment was significantly larger than that of the unconnected treatment (t<0.01). ANOVA analysis results indicated that the average daily dew amounts on different types of underlying surfaces were significantly different (P<0.01). Diurnal dynamics of dew amounts on different types of underlying surfaces exhibited similar double-peak trends. Dew deposition began at 22:00 and ended at 9:00 the next morning. The formation of dew is mainly affected by atmospheric temperature, soil surface temperature, relative humidity and wind speed. The results of this study will increase our understanding of the water source of vegetation in the lower reaches of the Tarim River during growing season and provide valuable scientific information for the restoration of vegetation in degraded regions.