干旱区生态环境知识资源中心(Arid): 基于稳定同位素的土壤水分运动特征

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	基于稳定同位素的土壤水分运动特征
其他题名	RESEARCH ON SOIL WATER MOVEMENT BASED ON STABLE ISOTOPES
	靳宇蓉; 鲁克新; 李鹏; 王琦; 张铁钢; 刘莹
来源期刊	土壤学报
ISSN	0564-3929
出版年	2015
卷号	52 期号:4 页码:792-801
中文摘要	土壤水分受降雨和地下水的共同补给作用,是陆地水循环的重要环节。通过模拟试验,结合土壤水同位素特征,以黄土高原黄绵土为研究对象,研究降雨入渗和地下水补给方式下土壤水分的运移变化特点。结果表明:土壤体积含水量随时间的延长而增大,最终趋于稳定,土壤水分的运移有明显滞后效应;土壤水氢同位素受补给水源、交换混合以及蒸发的影响,随时间的延长,补给水源的影响逐渐减弱,水分的交换混合和蒸发作用逐渐显现,土壤水最终达到动态平衡状态;两种补给条件下,土壤水运移方式均为活塞式推进,降雨人渗方式土壤水deltaD随土层深度的增加先减小后增大最终趋于稳定,表层0~5cm土壤水由于蒸发富集重同位素,5~20cm土壤水滞留时间最长,保水能力最强,地下水补给方式下土壤水deltaD随土层深度的增加而减小,上层土壤水deltaD由于蒸发富集重同位素,下层受地下水补给影响贫化;两种补给方式下土壤水deltaD与delta~(18)O有良好线性关系,降雨入渗方式土壤水蒸发分馏作用大于地下水补给方式,地下水补给具有较好的保水效果。
英文摘要	Soil moisture, affected jointly by rainfall and groundwater, plays an important role in terrestrial water recycling. Hydrogen and oxygen isotopes can be used as tracers to study water movement and migration in the soil. Stable isotope compositions of soil water can be used to reveal information about a number of hydrological processes in soil, including infiltration, evaporation, transpiration and percolation, which is difficult to obtain by other techniques. The Loess Plateau in northern Shaanxi with loessal soil as its dominant type of soil, is arid in climate and scarce in water resource. Anumber of studies documenting tracer movement in the soil column except for using loessal soil to study soil water movement under differential recharge based on hydrogen and oxygen isotopes. Researches on soil water movement and migration in loessal soil may help understand characteristics of soil water movement, guide local agricultural production and improve water utilization efficiency in the Loess Plateau. A simulation experiment using soil columns was carried out in the State Key Laboratory of Northwest Arid Area Experimental Ecology and Hydraulic Engineering, Xi’ an University of Technology. With the aid of isotope technology, exploration was done of temporal variation of soil water movement in loessal soil, temporal variation of distribution of isotope in soil water in the soil profile and relationship between oxygen and hydrogen isotopes in the soil water as affected by rainfall or groundwater, in an attempt to elaborate characteristcs of soil water movement in loessal soil relative to source of the recharge. During the experiment distributions of soil water content and hydrogen isotope in the soil profile were monitored 1, 3,5,10, 15, 20 and 30 days after the end of the recharge and relationship between oxygen and hydrogen isotopes in the soil water was fitted with a linear model. Results show that (1) being recharged with water from either source, rainfall or groundwater, the soil water increased in volumetric content as the time going on and leveled off in the end and that movement of the soil water obviously lagged behind. (2) Hydrogen isotope in the soil water was affected by source of recharge water, exchanging and mixing of the waters and evaporation of the water in the soil, and with the time going on,the effect of source of the recharge water gradually weakened, while the effects of exchanging and mixing of the waters and evaporation of the water in the soil gradually stood out. Eventually the soil water reached its dynamic balance. (3) When being recharged by rainwater or groundwater, soil water moved in a piston-driven way. With rainfall infiltrating into the soil, deltaD in the soil water first decreased, and then increased with increasing soil depth and eventually leveled off. The soil water in the surface 0 ~ 5cm soil layer was enriched in heavy isotope as a result of evaporation and the soil water in the 5 ~ 20cm soil layer stayed for the longest time, indicating that the soil layer is the highest in water retaining capacity. When being recharged by groundwater, the soil water decreased in deltaD with soil depth. The water in the upper soil layer was enriched in heavy isotope as a result of evaporation, and the water in the deep layer impoverished in isotope by recharge from groundwater. (4) Under either recharge modes, deltaD and delta~(18)O in the soil water displayed a nice linear relationship. Isotope fractionation effect of soil water evaporation was greater when soil water was recharged by rainfall than by groundwater. Soil water recharged by groundwater tended to stay longer in the soil. Obviously, rainfall, groundwater and soil water evaporation all have some impacts on soil moisture. The variation of soil water isotopes with a certain regularity. So adoption of underground irrigation in the Loess Plateau region is conducive to preservation of soil water for agricultural production.
中文关键词	降雨入渗 ; 地下水补给 ; 土壤水分运动 ; 稳定同位素
英文关键词	Rainfall infiltration Groundwater recharge Soil water movement Stable isotope
语种	中文
国家	中国
收录类别	CSCD
WOS类目	AGRICULTURE MULTIDISCIPLINARY
WOS研究方向	Agriculture
CSCD记录号	CSCD:5469477
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/233442
作者单位	西安理工大学, 西北旱区生态水利工程国家重点实验室培育基地;;教育部西北水资源与环境生态重点实验室, 西安, 陕西 710048, 中国
推荐引用方式 GB/T 7714	靳宇蓉,鲁克新,李鹏,等. 基于稳定同位素的土壤水分运动特征[J],2015,52(4):792-801.
APA	靳宇蓉,鲁克新,李鹏,王琦,张铁钢,&刘莹.(2015).基于稳定同位素的土壤水分运动特征.土壤学报,52(4),792-801.
MLA	靳宇蓉,et al."基于稳定同位素的土壤水分运动特征".土壤学报 52.4(2015):792-801.