Dynamics Of Soil Moisture And Salinity Of Newly Cultivated Oasis In Arid Desert Area

Soil is not only the basis of human survival and development, but also a primary factor that affects the agricultural productivity of newly cultivated oasis in arid desert area. It is very important for soil to improve the eco-environment and ensure the high and stable yields of agriculture. In the present dissertation, the movement and distribution of soil moisture and salinity in the Karamay newly cultivated oasis are analyzed by applying the method of trend line analysis. The results are summarized as follows:1 The salinized degree of the soil in development zone has remarkably decreased. The result indicated that the salinity in most area was obviously reduced after cultivating except a few areas that had a higher salinity due to abandonment or improper using. The average salinity experienced about from 3.07mg/kg to 2.09mg/kg, which indicates that the salinized degree of the soil in study area has been reduced in the mass with the reasonable cropping system.2 The groundwater depth has a notable change in study area. The average groundwater depth was reducing gradually with time in bearing time of the year 2005 and 2006. The average groundwater depth in bearing time of 2005 was 8.8m and that of 2006 was 6.4m, indicating that the groundwater table was distinctly lifted.3 The soil moisture and salinity are mostly affected by cropping structure. Cottons soil and melons soil results in a significant decrease in the soil salinity content. Corns and clovers are fibred crops; therefore the soil moisture of surface layer is rather high.4 Under the condition of dropping irrigation, water cannot be vaporized easily for the film cover on the surface, accordingly the phenomenon of returning salinity is not very graveness and water can take salinity to underground adequately. Contrastively, the flooding irrigation can bring abundant water and then more salinity of the surface layer to the underground, Therefore, the dropping irrigation is more abstemious than the flooding in the way of using water, and also more effective in pressing salinity.5 Lengths of being cultivated also have a great impact on soil moisture and salinity. The analysis by the method of space-exchanging-time shows that the soil salinity content has been decreasing gradually with the exploitation time passed by in study area, and the decreasing speed is first fast then slow, but it is contrary for the soil water. In a way, it shows that the salinity will be increasing but the moisture will be decreasing by degrees with the exploitation time gets longer.