Soil salinization features in arid areas farmland

Abstract: Xinjjiang is the biggest drought and saline area in China and soil salinization is of unique characteristics. In order to find features of soil salinization in arid area of northwest plains in China, in this study, we sampled from typical farmland in Xinjiang and carried out a series of laboratory experiment. Five soil samples were collected from the farmland for determination of their particle composition, and permeability coefficient. Based on these, the soils were classified into gravel, silty sand, fine sand, silt and loam. The rising height of capillary water from these soils with tap water as water resource was measured in 20 days of experiment. In another experiment, the salt accumulation was observed with NaCl and KCl in water as salt resources. The salinity in soil 5-cm depth was determined. The soil lithology, rising height of capillary water, and salinity were analyzed for their relationships. The results showed that the rising height of capillary water was fast in the first 12 days of experiment, and it was faster in soils with coarse particles. Meanwhile, the salt accumulation in soil 5-cm depth was obvious. However, the salt accumulation in soils with more fine particles could last for a longer period than those with coarse particles. In the end of experiment, the salinity in soils with coarse particles was smaller than that in fine particle-dominated soils. The rising height and rate of capillary water were most obvious in the first 3-4 days, which may indicate the control of saline soils should be in the early stage. In addition, the sandy soils were accessible to salt scale in 3-4 mm thickness, which may clog the capillary and prevent from the development of salinization. But, the thick salt scales also lead to difficulty in control of saline soils and they should be destroyed by surface ploughing. The results provide valuble information for understanding and control of soil salinization in arid area.