Distribution of soil moisture and salinity in shelterbelts and its relationship with groundwater level in extreme arid area, northwest of China

摘要

Because of the shortage of water source in the extreme arid area, generally, there are several years of no irrigation on mature shelterbelts. In this study, the shelterbelt soil in different texture were compared based on distribution analysis of the soil moisture and salt levels of shelterbelts under large-scale drip irrigation in Kalamiji Oasis in the lower reaches of Tarim River, Northwest China. The following conclusions were drawn. (1) In Kalamiji Oasis, the groundwater level declined at a rate of 0.5 m/a as a result of popularization of drip irrigation technology. (2) There was a larger heterogeneity in distribution for soil moisture in the sandy/loamy shelterbelt than in the clay shelterbelt. (3) Under non-irrigation conditions, sandy/loamy shelterbelt has lower soil moisture and salinity, and clay shelterbelt has higher soil moisture and salinity. (4) The shelterbelt with the shallowest groundwater depth had highest soil moisture level, and the shelterbelt with the deepest groundwater level had the lowest soil moisture content. (5) In sandy and loamy shelterbelts, the shelterbelts with the shallowest groundwater depths had the lower salinity levels and the shelterbelts with the deepest groundwater depths had the highest salinity levels. (6) In clay shelterbelts, the shelterbelts with the shallowest groundwater depths had the highest salinity levels, and the shelterbelts with the deepest ground-water depths had the lowest salinity levels. Additionally, it is essential to implement irrigation at least once a year.