含水量和容重对旱地耕层土壤热导率的影响及预测  

Effects of soil water content and bulk density on thermal conductivity of plough layer soil in arid land and its prediction

作　　者：卢奕丽 张猛 刘晓娜[3] 任图生[1] 王雅婧[1] Lu Yili;Zhang Meng;Liu Xiaona;Ren Tusheng;Wang Yajing(College of Resources and Environmental Sciences,China Agricultural University,Beijing 100193,China;College of Resources and Environmental Science,Hebei Agricultural University,Baoding 071001,China;College of Environment and Safety,Taiyuan University of Science and Technology,Taiyuan 030024,China)

机构地区：[1]中国农业大学资源与环境学院,北京100193 [2]河北农业大学资源与环境科学学院,保定071001 [3]太原科技大学环境与安全学院,太原030024

出　　处：《农业工程学报》2018年第18期146-151,共6页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(41671223);国家重点研发计划项目子课题:松嫩平原区基于合理耕层构造的全程机械化保护性耕作技术体系(2016YFD0300804-3);中国博士后科学基金资助项目(2016M600148)

摘　　要：土壤热导率是研究地表能量平衡和土壤水热运移过程中的一个基础参数。受土壤耕作、干湿交替和根系生长等过程的影响,耕层土壤的含水率和结构呈现较强的变异特征,而目前缺乏关于定量分析耕层土壤热导率变异特征的研究。该研究利用田间定位试验,采用热脉冲技术测定了含水率和容重变化条件下耕层土壤热导率的变异特征,并利用传递函数模型对耕层土壤热导率进行了预测。结果表明:含水率和容重是影响耕层土壤热导率变异的主要因子,而耕作强度和干湿交替是这种变异的关键驱动力;与翻耕和旋耕处理相比,免耕处理提高了土壤容重和含水率,从而增大了土壤热导率;在干湿交替作用下,翻耕后土壤容重逐步增加,耕层热导率也呈现上升趋势,波动幅度与含水率的变化相关。基于含水率、容重和质地信息,土壤热导率传递函数模型可以给出可靠的田间土壤热导率估计值,其均方根误差和平均偏差分别为0.09和-0.01 W/(m·K);考虑耕层土壤容重的动态信息,可以提高该模型预测土壤热导率的准确性。Soil thermal conductivity(λ)is a key parameter for studying surface energy balance and coupled heat and water transfer in soil.λcan be obtained by heat pulse method or semi-empirical or empirical models,with both models based on the information of soil texture,water content(λ)and bulk density(λb).The pedotransfer model has the advantages of simple form and having no requirement of soil minerology information.This pedotransferλmodel,however,has not been applied comprehensively under field conditions whereλdisplays strong spatial and temporal variability.The objectives of this study are to determine the spatial and temporal changes ofλas related toλandλb in tilled soil layers,and to test the feasibilities of the pedotransferλmodel for estimating fieldλwith the information of soil texture,λandλb.Two independent field experiments were conducted:one study of different tillage treatment’s effect onλvariations and another post-tillage soil structure dynamic study onλat 2 soil depths due to alternate wetting and drying.For the tillage method study,λmeasurements were carried out in the field,and soil cores were taken to determineλandλb gravimetrically.For the soil structure dynamic study,in situλchanges were monitored with time domain reflectometry(TDR)technique,the dynamicλb values were determined gravimetrically after each rainfall event,and the correspondingλλdata were obtained from the collected intact soil cores by heat-pulse sensors.The results showed thatλandλb were the key factors that affectedλin tilled soil layers.In 0-10 cm soil layer,theλ,λandλb values in no tillage treatment plot were significantly higher than those of the moldboard and rotary tillage plots.Soilλvalues of the 10-20 cm soil layer were higher than that in the 0-10 cm layer,and the trends were consistent with that ofλandλb regarding tillage treatment and soil depth.For the post-tillage soil structure dynamic study,λb was increased gradually with time and soil depth and became relatively stable after 4 wetting/dr

关 键 词：土壤 含水率 农田 热导率 耕作措施 容重 热脉冲技术 

分 类 号：S152.8[农业科学—土壤学]