Soil water infiltration process in north and south mountains of Lanzhou City based on stable isotope
Based on precipitation and soil water isotope data at different elevations in the north and south mountains of Lanzhou from April to October 2018,the lc-excess method and the lc-excess equilibrium equation were used to qualitatively and quantitatively analyze the soil water infiltration process in this area.The infiltration process of soil water,indicated by the soil water lc-excess value,was verified by correlation analysis and single factor analysis.The results showed that there are obvious variations in soil water content in the study area on a monthly scale and at different depths,with loss dominating from April to June and accumulation dominating from July to September.The soil water content in the high altitude areas was found to be greater than that in the low altitude areas,and the soil water content in the north mountains was found to be greater than that in the south mountains.Stable isotopes of soil water at each sampling site we found to be most depleted from August to September.At increasing soil depth,soil water isotopes showed a trend of gradual depletion and stabilization.The soil water lc-excess results showed that the piston flow mode and the priority flow mode co-exist in the infiltration and recharge process of soil water in the study area.The priority flow signal appeared at all sampling sites from July to August.The contribution of the preferred flow pattern to deep soil water was higher at the low elevation sampling sites than at the high elevation sampling sites.The soil water content and soil water lc-excess were found to be positively correlated.The monthly scale and depth of soil water lc-excess were not significantly different between the north and south mountain,indicating that the infiltration and recharge patterns of soil water in the north and south mountains are the same,and that both are dominated by the piston flow infiltration pattern of precipitation recharge.However,in the south mountains,where there is greater vegetation cover,the preferential flow pattern signal appeared more often,especially in July and August,when precipitation is concentrated.Based on the soil water infiltration and replenishment processes in the north and south mountains,it the selection of salt-and drought-tolerant,shallow-rooted shrubs and perennial grasses is recommended for the north mountains,while reasonable irrigation is recommended in the south mountains during the plant growing season(from April to June).The results of this study provide a theoretical reference for understanding the hydrological process in the north and south mountains of Lanzhou.
stable isotopelc-excess methodpiston flowpreferential flownorth and south mountains of Lan-zhou
国家科技期刊平台
NSTL
万方数据
维普
