湘西北红壤丘陵区土壤水运移的稳定性同位素特征  

Characteristics of Soil Water Movement Using Stable Isotopes in Red Soil Hilly Region of Northwest Hunan

作　　者：田日昌[1,2] 陈洪松[1] 宋献方[3] 王克林[1] 杨青青[1] 孟薇[1] 

机构地区：[1]中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,长沙410125 [2]中山市环境保护科学研究所,中山528403 [3]中国科学院地理科学与资源研究所陆地水循环及地表过程重点实验室,北京100101

出　　处：《环境科学》2009年第9期2747-2754,共8页Environmental Science

基　　金：中国科学院知识创新工程重要方向项目(KZCX3-SW-441);中国科学院知识创新工程领域前沿项目(01200220055413);中国科学院院长奖获得者科研启动专项资金项目

摘　　要：稳定同位素技术为土壤水运移研究提供了新的研究手段.通过对红壤丘陵区降水和不同深度土壤水稳定性氢氧同位素的示踪,研究了2种不同植被类型（油茶林、玉米地）土壤水分运移过程.结果表明,该区大气降水稳定性同位素存在明显的降水量效应和季节效应.油茶林0～50 cm、玉米0～40 cm土壤水氢氧同位素值随深度增大而增大,但干旱时段降水后表现出相反的趋势;油茶林50 cm、玉米40 cm以下土壤水氢氧同位素值随深度增大而减少,蒸发影响微弱.油茶林入渗率受降水量影响明显,大雨后2～3 d入渗率约为50～100 mm/d,之后入渗率明显减慢,50 cm土层常成为阻隔层.玉米地由于通透性差,入渗率更低.红壤丘陵区土壤水氢氧同位素值变化主要是受前期降水形成的混合水样的影响,蒸发影响次之.油茶林蒸发强度小于玉米地,但蒸发深度较玉米地深.Stable isotope techniques provide a new approach to study soil water movement. The process of water moment in soils under two kinds of plant types （oil tea and corn） were studied based on the observed values of hydrogen and oxygen isotopes of precipitation and soil water at different depths in red-soil sloping land. The results showed that stable isotopes of precipitation in this area had obvious seasonal effect and rainfall effect. The stable isotopes at 0-50 cm depth in oil tea forestland and at 0-40 cm depth in corn cropland increased with the increase in depth, respectively, but they had the opposite tendency after rainfall in arid time. The stable isotopes decreased with the increase in depth below 50 cm depth in oil tea forestland and below 40 cm depth in corn cropland where evaporation influence was weak. The infiltrate rate of soil in oil tea land was affected by precipitation obviously, and it was about 50-100 mm/d after 2-3 days in heavy rain, slowed sharply later, and soil water at 50 cm depth often became a barrier layer. The permeability of soil in corn land was poor and the infiltration rate was lower. The change of stable isotopes in soil water in red soil hilly region was mainly affected by the mixing water which was formed by the antecedent precipitation, and evaporation effect took the second place. The evaporation intensity in oil tea land was lower than that in corn land, but the evaporation depth was higher.

关 键 词：红壤丘陵区 土壤水 蒸发 入渗 稳定性同位素 

分 类 号：X144[环境科学与工程—环境科学]