Salt distribution characteristics of Taklimakan Desert highway shelterbelt under saline water drip-irrigation

The paper investigated the soil salinity and the distribution characteristics of different salt ions for the soils under drip irrigation with saline water in Taklimakan Desert highway shelterbelt,Xinjiang,China. The experiment included five treatments,in which controlled with the different mineralization degrees of irrigation water were:29.70(Well No.1),25.90(Well No.2),20.99(Well No.8),16.95(Well No.14)and 5.75 g·L-1(Well No.18),respectively. The results showed that salt content and soil ion composition were significantly affected by saline water irrigation. Soil salinity increased with increasing irrigation water salinity levels. Depending on irrigation water chemistry,soil salinity composition was dominated by Cl-,Na+and SO42-. The distribution characteristics of different salt ions in soil profiles were different. While Cl-,Na+,Mg2+and SO42-had relatively uniform distributions in soil profiles,i.e.,their concentration was the lowest in the vertically downward direction of emitters and was increased with the distance away from emitters' radial direction,the distribution of Ca2 +and HCO3-in soil profiles were significantly different. In the horizontal direction,with the distance away from emitters,HCO3-manifested as gathering to the upper layers,while Ca2 +showed up as leaching into the deeper soil layers. The results have a theoretical and applicable value for the reasonable development and utilization of the saline water as well as the sustainable development of the sheltering forest in extremely arid region.