Dissipation and movement of soil water in artificial forest in arid oasis areas: Cognition based on stable isotopes

Abstract

• The average evaporation loss of soil water in the artificial forest is higher in summer. • The soil water recharge mode of the artificial forest is preferential flow recharge. • The artificial forest construction increased the soil water consumption rate in oasis area. • The construction mode of combining arbor, shrub and grass can reduce soil water consumption. Large-scale construction of artificial forests in arid oasis areas plays a role in wind prevention and sand fixation, vegetation increase and landscape improvement. However, due to the extremely strong evapotranspiration in the arid areas, the construction of artificial forests may greatly increase the consumption of water resources. Therefore, it is necessary to evaluate and weigh the benefits of its ecology, landscape and water resource utilization. Based on different water isotopic data (soil water, precipitation) and related hydrometeorological data of typical poplar plantation in the middle and lower reaches of Shiyang River Basin from 2018 to 2019, this study evaluated the soil evaporation loss rate and water storage capacity of artificial forest and revealed the mechanism of soil water movement. The results showed that: (1) The average soil evaporation loss in the artificial forest was 21.30%, which was higher in spring and summer and lower in autumn and winter; (2) The soil water recharge from the artificial forest has the characteristics of preferential flow recharge, with long retention of precipitation in the soil, and full mixing of newly recharged water with original water; (3) The artificial forest increased the water storage capacity of deep soils (80–100 cm) in the oasis area, but the water consumption rate also correspondingly increased. Artificial forests must rely on water input to maintain normal growth, and its own water consumption rate and soil evaporation loss are high. Therefore, ecological, landscape, and water resource utilization benefits should be considered when constructing artificial forests in arid oasis areas where water resources are scarce.