Effects of biochar on soil water retention curves of compacted clay during wetting and drying  

作　　者：James Tsz Fung Wong Ka Lai Chow Xun Wen Chen Charles Wang Wai Ng Ming Hung Wong 

机构地区：[1]Department of Civil and Environmental Engineering,The Hong Kong University of Science and Technology,Clear Water Bay,Kowloon,Hong Kong,SAR,China [2]Department of Geography,Hong Kong Baptist University,Kowloon Tong,Hong Kong,SAR,China [3]Consortium on Health,Environment,Education and Research(CHEER),Department of Science and Environmental Studies,The Education University of Hong Kong,Tai Po,Hong Kong,SAR,China [4]Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control,School of Environmental Science and Engineering,Southern University of Science and Technology,Shenzhen 518055,China [5]State Environmental Protection Key Laboratory of Integrated Surface Water Groundwater Pollution Control,School of Environmental Science and Engineering,Southern University of Science and Technology,Shenzhen 518055,China

出　　处：《Biochar》2022年第1期1117-1130,共14页生物炭（英文）

基　　金：the Collaborative Research Fund provided by the Research Grants Council of Hong Kong(HKUST6/CRF/12R);Shenzhen Science and Technology Program(KCXFZ20201221173601003).

摘　　要：Compacted clay possesses a low water permeability and has been widely used in geo-environmental facilities such as landfill cover systems.Recent studies revealed the potential applications of compacted biochar-amended clay(BAC)as an alternative landfill cover soil.However,the effects of biochar on the soil water retention curves(SWRCs)of clay at low suction are not known.This study can help fill this knowledge gap by measuring the wetting and drying SWRCs of clay and BAC(20%biochar).Soils were compacted in instrumented soil columns and subjected to a wetting and drying cycle,and soil water content and suction were measured along with the soil depth.BAC was saturated faster when compared with clay.Upon drying,the soil water content of clay at 65 mm depth dropped to almost zero,while about 5%of water was retained in BAC.It showed that biochar increased the soil water retention capacity of compacted clay upon drying.SWRCs showed that biochar-clay composite possesses a higher soil water retention capacity at a low soil suction range(<1000 kPa)compared with clay alone.It revealed the benefits of using compacted biochar-clay composite as a hydraulic barrier to minimize desiccation-induced cracks and potentially promote its serviceability,especially in arid and semi-arid regions.The composite is also a carbon sink material that can reduce landfill gas emissions and pollutant leaching.

关 键 词：Soil amendment Biochar-clay composite Soil carbon Soil suction Soil depth 

分 类 号：S15[农业科学—土壤学]