极端干旱区不同水分条件下胡杨林生态耗水特征

以极端干旱区胡杨林为研究对象,探究不同水分条件下胡杨林土壤水分运动规律和胡杨生态耗水特征。结果表明:HYDRUS-1D模型对极端干旱区胡杨林土壤水分运动和蒸散发过程具有良好的模拟效果。不同水分条件下胡杨林土壤水分运动特征和生态耗水变化差异明显。随着下垫面水分条件趋于湿润,土壤水分含量和湿润锋入渗深度均出现增加,入渗深度分别达到100,120,150cm。下垫面水分条件改变导致土壤水分存蓄情况发生变化。下垫面水分补给增加的同时胡杨林蒸散发呈明显增加,其中植被蒸腾增加显著。随着水分条件逐渐湿润植被蒸腾占总蒸散比例由55%升至65%。研究显示,随着下垫面水分条件逐渐湿润,极端干旱区胡杨林生态耗水量逐渐增加,其中植物蒸腾消耗是造成水分耗散增加的主要原因。

Ecological Water Consumption Characteristics of Populus euphratica Forest Under Different Water Conditions in Extremely Arid Area

Taking Populus euphratica forests in extremely arid area as the research object, we studied the soil water movement and the ecological water consumption characteristics under different water conditions. The results showed that the HYDRUS-1D model had a good simulation effect on soil water movement and evapotranspiration in forestland in extremely arid regions. The soil water movement and ecological water consumption of Populus euphratica forests under different water conditions were significantly different. As the moisture condition of the underlying surface tended to be wet, the soil moisture content and the wetting front infiltration depth increased, and the infiltration depth reached 100 cm, 120 cm and 150 cm, respectively. The changes in moisture conditions on the underlying surface resulted in the changes in soil moisture storages. When the water supply of the underlying surface increased, the evapotranspiration of Populus euphratica forest increased significantly, and the transpiration increased significantly. The percentage of transpiration in the total evapotranspiration gradually increased from 55% to 65% as the moisture conditions became wet. Studies showed that with the gradual wetting of the underlying surface moisture conditions, the ecological water consumption of Populus euphratica forests in the extremely arid regions is gradually increasing, and transpiration is the main reason for the increase of water dissipation.