干旱区生态环境知识资源中心(Arid): 含水量和容重对旱地耕层土壤热导率的影响及预测

Arid

	含水量和容重对旱地耕层土壤热导率的影响及预测
其他题名	Effects of soil water content and bulk density on thermal conductivity of plough layer soil in arid land and its prediction
	卢奕丽 1; 张猛 2; 刘晓娜 3; 任图生 1; 王雅婧 1
来源期刊	农业工程学报
ISSN	1002-6819
出版年	2018
卷号	34 期号:18 页码:146-151
中文摘要	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。
英文摘要	Soil thermal conductivity (lambda) is a key parameter for studying surface energy balance and coupled heat and water transfer in soil. lambda can be obtained by heat pulse method or semi-empirical or empirical models, with both models based on the information of soil texture, water content (theta) and bulk density (rhob).The pedotransfer model has the advantages of simple form and having no requirement of soil minerology information. This pedotransfer lambda model, however, has not been applied comprehensively under field conditions where lambda displays strong spatial and temporal variability. The objectives of this study are to determine the spatial and temporal changes of lambda as related to theta and r b in tilled soil layers, and to test the feasibilities of the pedotransfer lambda model for estimating field lambda with the information of soil texture, theta and r b. Two independent field experiments were conducted: one study of different tillage treatment’s effect on lambda variations and another post-tillage soil structure dynamic study on lambda at 2 soil depths due to alternate wetting and drying. For the tillage method study, lambda measurements were carried out in the field, and soil cores were taken to determine theta and r b gravimetrically. For the soil structure dynamic study, in situ theta changes were monitored with time domain reflectometry (TDR) technique, the dynamic r b values were determined gravimetrically after each rainfall event, and the corresponding lambda data were obtained from the collected intact soil cores by heat-pulse sensors. The results showed that theta and rhob were the key factors that affected lambda in tilled soil layers. In 0-10 cm soil layer, the l, theta and rhob values in no tillage treatment plot were significantly higher than those of the moldboard and rotary tillage plots. Soil lambda values of the 10-20 cm soil layer were higher than that in the 0-10 cm layer, and the trends were consistent with that of theta and rhob regarding tillage treatment and soil depth. For the post-tillage soil structure dynamic study, rhob was increased gradually with time and soil depth and became relatively stable after 4 wetting/drying (W/D) cycles, i.e., from 0.98 to 1.16 g/cm~3 for the 0-5 cm layer, and from 1.09 to 1.28 g/cm~3 for the 5-10 cm layer. The magnitude of the change was relatively small among the first 3 W/D cycles when the degrees of saturation were relatively low, and rhob in the 5-10 cm layer reached the maximum after the fourth W/D cycle when the soil was nearly saturated, with the change became less significant thereafter. Comparison between measured and modeled values showed that the pedotransfer lambda model provided reliable lambda with RMSE of 0.09 W/(m·K) and mean bias of -0.01 W/(m·K). Our analysis also highlighted the fact that when rhob varied over time due to soil structure change, using a constant rhob (measured either right after tillage or at the end of the experiment) would introduce larger errors for lambda estimations. The pedotransfer lambda model for estimating soil lambda could be useful for simulating heat transfer in tilled soil layers.
中文关键词	土壤 ; 含水率 ; 农田 ; 热导率 ; 耕作措施 ; 容重 ; 热脉冲技术
英文关键词	soils moisture farmland thermal conductivity tillage practice bulk density heat pulse technique
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:6334717
来源机构	中国农业大学
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/237990
作者单位	1.中国农业大学资源与环境学院, 北京 100193, 中国; 2.河北农业大学资源与环境科学学院, 保定, 河北 071001, 中国; 3.太原科技大学环境与安全学院, 太原, 山西 030024, 中国
推荐引用方式 GB/T 7714	卢奕丽,张猛,刘晓娜,等. 含水量和容重对旱地耕层土壤热导率的影响及预测[J]. 中国农业大学,2018,34(18):146-151.
APA	卢奕丽,张猛,刘晓娜,任图生,&王雅婧.(2018).含水量和容重对旱地耕层土壤热导率的影响及预测.农业工程学报,34(18),146-151.
MLA	卢奕丽,et al."含水量和容重对旱地耕层土壤热导率的影响及预测".农业工程学报 34.18(2018):146-151.