水分胁迫对半干旱典型草原土壤水分变化特征的影响  

Effects of Water Stress on Soil Moisture in Semiarid Typical Steppe

作　　者：侯琼[1] 苗百岭 王英舜[3] 董春丽[3] HOU Qiong;MIAO Bailing;WANG Yingshun;DONG Chunli(Ecological and Agricultural Meteorological Center of Inner Mongolia,Hohhot 010051,China;Meteorological Research Institute of Inner Mongolia,Hohhot 010051,China;Xilinhot National Climate Observing Station of Inner Mongolia Autonomous Region,Xilinhot 026000,Inner Mongolia,China)

机构地区：[1]内蒙古生态与农业气象中心,内蒙古呼和浩特010051 [2]内蒙古气象科学研究所,内蒙古呼和浩特010051 [3]内蒙古自治区锡林浩特国家气候观象台,内蒙古锡林浩特026000

出　　处：《干旱气象》2020年第6期987-993,共7页Journal of Arid Meteorology

基　　金：公益性行业(气象)科研专项(GYHY201506001-3);国家自然科学基金项目(31960261);内蒙古自然基金项目(2019MS03028)共同资助。

摘　　要：了解土壤水分时空变化和水分胁迫影响特征是研究草原地区耗水规律与干旱判别的基础。选取内蒙古锡林浩特半干旱典型草原群落,通过分析不同水分梯度下多层次土壤含水量连续观测数据,研究水分供给变化对土壤水分季节变化规律和垂直分布特征的影响。结果表明:正常年份土壤含水量季节变化呈双峰曲线特征,春季返青期和7月雨季为峰值期,5月下旬和9月初多为低谷期。50 cm以上土层水分垂直变化明显,其中0~30 cm土层水分波动剧烈,60 cm以下土层水分变化明显减小。水分胁迫会改变土壤水分的季节变化规律,减小变幅,胁迫严重时会造成季节变化曲线失去双峰特征而变得平滑,并使耗水向深层发展,水分变化敏感区域下伸至60~80 cm土层。土壤水分季节变化和土层深度是分析水分胁迫与生态系统相互作用和制定土壤干旱指标时不容忽视的因素。Adequate understanding of water stress influences on the temporal-spatial variations of soil moisture is crucial for studying water consumption and drought identification in grasslands.Based on soil volumetric water content data monitored in multi-layer soil under two water supply conditions during 2016-2017,soil water status,the seasonal variations and the vertical distribution in the typical steppe in Xilinhot of Inner Mongolia were investigated.The results show that soil water showed distinct seasonal variations in a normal year with dual peaks curve.That was,soil volumetric water content reached the peak in the spring green-up and the rainy season(July),and then it decreased and reached the minimum value in the late of May and the early of September.Soil water content of top 50 cm layer also exhibited marked variation,especially for 0-30 cm layer.The water stress changed the seasonal dynamics of soil moisture(i.e.reduction in the amplitude).More importantly,serious water stress caused that the dual peaks curve failed(becoming smooth),and the water consumption happened in the deeper layer.Moreover,the sensitive area of soil water change extended to the 60-80 cm soil layer.The results highlight that seasonal variations in soil moisture and soil depth are two valuable factors analyzing the interactions between water stress and ecosystem as well as soil drought index.

关 键 词：水分胁迫 土壤水分 变化特征 典型草原 

分 类 号：S152.7[农业科学—土壤学]