Quantitative evaluation of consecutive soil moisture evaporation during the non-monsoon season based on stable isotopes in the eastern Loess Plateau
Soil moisture is the key link between the atmosphere,water circle and soil circle,and its evaporation loss is crucial to understanding the process of soil water movement in semi-arid areas and maintaining the regional ecological environment.Based on continuous collection of long-term stable isotopes in soil water in the typical region of the eastern Loess Plateau during the non-rainy period in growing season,this study systematically analyzes the spatial and temporal variations in soil moisture content and its hydrogen and oxygen stable isotopes,explores the soil water evaporation loss at different soil depths under consecutive evaporation conditions using the Craig-Gordon model,and reveals the internal relationship between soil evaporation loss and major regional environmental elements.Results indicate that:1)The soil moisture content shows a gradual de-creasing trend,δ18O and δ2H in soil water appears fluctuation among different months.2)Enriched soil water δ18O appears in the 0-20cm soil layer,and gradually decreases with the increase of the soil depth,and the minimum value of soil water δ18O appears in the 40-60cm soil layer,and is gradually enriched with increasing soil depth.3)Overall,the maximum value of soil moisture evaporation loss is observed in May,and the minimum value is observed in April,which shows a fluctuating decreasing trend with increasing soil depth.4)Regional soil moisture evaporation loss is positively correlated with regional air temperature,wind speed and potential evapotranspiration,and negatively correlated with soil water content and relative humidity.The correlation between soil moisture evaporation loss and environmental elements gradually weaken with increasing soil depth.5)The results of multiple linear regression analysis show that the correlation between soil water evaporation loss and external environment elements is weak while precipitation less than 5mm,whereas there is a significant linear relationship between soil water evaporation loss and external environmental elements(P＜0.05)while the precipitation more than 20mm.The results of this study have important implications for the rational and optimal allocation of water resources in the Loess Plateau and the high quality of regional agriculture.
soil moisturehydrogen and oxygen isotopesconsecutive evaporation losscontrolling factor
万方数据
维普
