The Elementary Study Of Moisture Absorption And Water Condensation Of Three Kinds Of Underlying Surfaces In Mu Us Sandy Land

The microclimate of different underlying surfaces in arid regions has influence on the moisture absorption and water condensation of soil, in order to discuss this influence, the weighing method was adopted in this paper to research diurnal variations, monthly changes and altitudinal changes characters of moisture absorption and water condensation of the different underlying surfaces such as Sabina vulgaris community, Artemisia ordosica Community and bare land at Mu Us Sandy land development and research center courtyard. Through the correlation analysis and principal component analysis between moisture absorption and water condensation of soil with microclimate factors,the results are summarized as follows:(1) It is an extremely physical course that the moisture absorption and water condensation falls in soil. Many kinds of meteorological factors influence the amount of condensation, among these factors, the air humidity and air temperature of near-surface are the basic factors,while other factors play a role by decorating two factors. All the factors change along with change of conditions of underlying surface.(2) Within a whole day, the course of moisture absorption and water condensation of soil is departed into two phases: the first phases starts after sunset, the second phase starts before sunrise, condensation occurs when the soil temperature is lower than or equal to the dew-point temperature. The research result shows that the amount of condensation reaches maximum when the time is between 19:00 and 22:00. Since then, the amount decreased gradually.(3) In the periods from May to November, the amount of the condensation is the largest in August and the smallest in May and June, the amount in July and September is in the middle of them. The amount of condensation in Sabina vulgaris community, Artemisia ordosica Community and bare land are 2.06mm, 1.91mm and 1.75mm respectively. The characteristics of underlying surfaces influences on the amount of condensation and the difference was remarkable(p=0.05).(4) The result of altitudinal change of the amount indicates:In the same underlying surface, the amount of condensation at 20cm above the ground is more than the one which is at 10cm above the ground and ground surface. At the same height of different kinds of underlying surface, the amount of condensation in the Sabina vulgaris community is the most ,and the one in the Artemisia ordosica Community is more , the one in the bare land is the least.(5) The mechanical composition of soil are the internal factors which influence the amount of condensation, when the soil contains more clay particles, it has the larger surface area and it can adsorb more water, and this is in favor of the formation of moisture absorption and water condensation. The soil clay particles content of three underlying surface are as follows: Sabina vulgaris most ,Artemisia ordosica more, the bare land least.(6) The result of the principal component analysis of meteorological factors indicates:In the view of collectivity, during the period of experimentation, the average temperature, the nights temperature and the average absolute humidity have the biggest contribution to the amount of the moisture absorption and water condensation of soil; the relative humidity, the average relative humidity of night and the average temperature have the biggest contribution in wet season; the average absolute humidity of night, the average absolute humidity during 24h and the average temperature have the biggest contribution in dry season.