Effects Of Different Environments On Soil Condensation Water In Mu Us Sandland

Water shortage is the most important constraint factor of ecological restoration in Mu Us Sandland.The condensation water is a kind of non-rainfall water input,which plays an important role in the ecological restoration of desertification areas.In order to study the effect of different environmental factors on the soil condensation water in Mu Us Sandland,the experiment was carried out at the Yanchi Desert Ecosystem Observation Station in Ningxia from April to May in 2014.Taking the soil moisture as the research object,the field experiment was carried out in,August-September 2015,April-May 2016,and the condensation water was measured by the micro-lysimeters weighing nethod.According to the results of the pre-experiment,the field test observation project was selected,including meteorological factors(air temperature,soil temperature and water content,relative humidity,wind speed,rainfall),underlying surface factor(bare sand,biological crust,grassland and shrub land),topography(slope position,slope direction).The main conclusions are as follows:(1)The results of soil moisture influencing factors show that the amount of soil absorbed water increases with temperature and air relative humidity,and there is a significant exponential correlation between soil absorbed water amount temperature and relative humidity.The average soil absorbed water amount of lichen,lichen,slope top,bottom and grassland was 0.910 g,0.915 g,0.518 g,0.566 g and 0.818 g respectively,indicating that the average soil absorbed water amount of crust(lichen and moss)was the largest,followed by grassland,and bare sand soil absorbed water is the smallest.The soil absorbed water anount at the bottom of the dune is higher than that of the top of the dune.(2)Soil condensation water amount decreased with air temperature,surface temperature and air relative humidity,but increased with gas-ground temperature difference,and there was a significant linear correlation between them(P<0.05).Condensation water amount and wind speed were inverted quadratic relationship,when the wind speed was 1.25 m/s,the condensation water was the most.Rainfall is conducive to the formation of condensation water.After rain,the average daily condensation water increased first and then reduced,the third day of condensation water up,then gradually reduce the amount of condensate until it stabilized.(3)The influence of the underlying surface on the soil condensation water shows that there was a significant difference(P<0.05)in the amount of condensation water in bare sand,biological crust,grassland and shrub land,but there was no significant difference in the condensation water amount between the crust and the grassland(P>0.05).The average daily condensation water of the bare sand(0.21 mm),followed by grassland(0.16 mm)and crust(0.19 mm),and the shrub land was the least(0.07 mm).The duration of the four types of condensate is different,and the duration of the shrub is the longest.(4)By analyzing the soil condensation water of dune,it can be seen that the daily condensation water amount of shady slope and sunny slope decreases with the increase of slope height.The condensation rate and condensation water amount of the shady slope increased with the increase of slope height(excluding the top of the dune).The condensation rate and condensate water content of the sunny slope decreased with the slope(P<0.05),and there was a significant linear correlation between condensate and slope height(P<0.05).The average daily condensate of the shady slope was 0.31 mm higher than that of the sunny slope 0.26 mm,and the daily average condensation water of the slope was the least(0.15 mm).The environmental factors affecting the soil condensation water in Mu Us Desert were discussed.At the bottom of the dune,or the surface of the biological crust is conducive to the formation of condensation water,consider the restoration of vegetation.The results could provide technical support for water cycling mechanism,water resources evaluation,water and heat balance to the ecosystem management and ecological restoration of the Mu Us Sandland,which is of great significance to the integrity and sustainability of the local ecosystem.