Soil Development and Plant Growth Under Saline Water Irrigated Shelterbelt Along Tarim Desert Highway.

Water scarcity is a world-wide problem, especially in desert ecosystems. To overcome this shortage, saline groundwater is increasingly being used, although it has risks of increasing soil salinity and causing plant salt toxicity. In this study, we investigated the soil development and plant growth under artificial shelterbelt irrigated with saline water along the Tarim Desert Highway. The results showed that soil salts and nutrients significantly accumulated at the soil surface (crust and 0-10 cm layers) with saline irrigation, but the soil salinization did not increase within the 40-60 cm soil depth where abundant lateral roots germinated. While the deepest main root system was 200 cm for Tamarix, it extended to about 150 cm for other two species studied (Tamarix and Calligonum). More than 87% of the biomass of the lateral roots was present in the 20-80 cm soil depths for the three species, however, no active absorbing roots were found within the 0-10 cm soil depths where the salts had accumulated. Consequently, saline water irrigation did not influence the normal growth of adaptive plants, which may be attributed to the plant adaptability to salt stress through root morphology adjustment. Therefore, saline water irrigation may be beneficial for soil nutrient accumulation and accentuates the potential uses of these sandy soils. After 7-yrs irrigation with nutrient accumulation, soil under shelterbelt has progressively formed, as indicated by increased size, stability and fractal dimension of soil aggregate, and consequently combat the desertification. In summary, saline groundwater irrigation offers potential advantages and opportunities for plant growth on sandy soils in a desert environment where saline water is the sole water resource for plants.