冬季沙漠沙丘土壤凝结特征及来源分析  

Characteristics and source of soil condensation in desert dune in winter

作　　者：司前程 李锦荣[2] 崔万新 杨锋[1] SI Qiancheng;LI Jinrong;CUI Wanxin;YANG Feng(Inner Mongolia Agricultural University,Hohhot 010018;Institute of Water Resources for Pastoral Area of the Ministry of Water Resources of China,Hohhot 010020,China)

机构地区：[1]内蒙古农业大学,呼和浩特010018 [2]水利部牧区水利科学研究所,呼和浩特010020

出　　处：《干旱区资源与环境》2021年第6期44-51,共8页Journal of Arid Land Resources and Environment

基　　金：十三五重点研发(2016YFC0501004);内蒙古自然基金(2019MS04001)资助。

摘　　要：在乌兰布和沙漠沿黄段流动沙丘开展冬季土壤凝结水研究,揭示冬季沙丘表层含水率增加的来源机制,探究冬季土壤凝结水的发生特征、来源及影响因素。结果表明:冬季沙丘确有土壤凝结水产生且能够一直存在于土壤中,发生时段在下午16点~次日8点左右。日变化呈单峰曲线,日变化过程可分为吸湿阶段,凝结阶段、蒸散消耗阶段;沙土初始含水量会影响土壤凝结水的发生层次,主要在地面以下4~6cm之间。其中烘干干沙与自然干沙的影响深度分别为6cm和4cm。空气水汽主要发生在沙土表层0~2cm之间,土壤水汽影响的最大深度为6cm;土壤凝结水的增重主要发生在凝结阶段。水汽来源以空气水汽为主,空气水汽所占比例分别为自然干沙70.81%,烘干干沙66.04%;土壤凝结水与相对湿度呈极显著正相关(相关系数r值在0.659~0.775),不同初始含水量对温度的相关性有差异,自然干沙与地温、近地层空气温度呈显著相关(r值在-0.562~-0.747)。烘干沙土与地温、露点温度、空气温度相关性不显著;冬季土壤凝结水的存在能够改变沙土的表面状态(含水量、孔隙冰),有效的提高沙粒的启动风速阈值,限制风蚀的发生。Winter soil condensation was studied in the flowing dunes along the Yellow river section of UlanBuh Desert,to reveal the source mechanism of the increase of surface water content of dune in winter,and explore the occurrence characteristics,sources and influencing factors of soil condensate in winter.The results show that the soil condensate occurs in the dune in winter,and it can exist in the soil all the time,and it occurs from 16 PM to 8 AM the next day.The diurnal variation shows a single peak curve,and the diurnal variation process can be divided into hygroscopic stage,condensation stage and evapotranspiration consumption stage.The initial moisture content of sandy soil affects the occurrence levels of soil condensate,which is mainly between 4~6 cm below the ground.The depth of dried sand and natural dry sand are 6 cm and 4 cm,respectively.The atmospheric vapour mainly occurs in the 0-2 cm surface layer of sandy soil,and the soil moisture maximum influence depth is 6 cm.The weight gain of soil condensate mainly occurs in the condensation stage.The atmospheric vapour is the main source of soil water vapor,and the proportion of air water vapor naturally dry sand is 70.81%and in dry sand is 66.04%of total soil water vapor,respectively.There is a significant positive correlation between soil condensate and relative humidity(the correlation coefficients range from 0.659 to 0.775).Different initial water contents have different correlations with temperature.Natural dry sand is significantly correlated with ground temperature and surface air temperature(the correlation coefficients range from-0.562 to-0.747).There is no significant correlation between dried sand and ground temperature,dew point temperature and air temperature.The existence of soil condensate in winter can change the surface state of sand(water content,pore ice),effectively improve the threshold of sand starting wind speed,and limit the occurrence of wind erosion.

关 键 词：沙丘 冬季 土壤凝结水 乌兰布和沙漠 

分 类 号：S152.[农业科学—土壤学]