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- Title
Long‐Term Performance on Drought Mitigation of Soil Slope Through Bio‐Approach of MICP: Evidence and Insight from Both Field and Laboratory Tests.
- Authors
Ji, Xin‐Lun; Tang, Chao‐Sheng; Pan, Xiao‐Hua; Cai, Zhao‐Lin; Liu, Bo; Wang, Dian‐Long
- Abstract
Drought is a serious global environmental issue that causes water resource scarcity and threatens agriculture and food supplements. This study aims to investigate the long‐term performance of an eco‐friendly technique‐microbial induced carbonate precipitation (MICP) on drought mitigation at field and laboratory scales. Seven in‐situ slopes treated with different MICP rounds and cementation solution concentrations were subjected to 16‐month weathering. Tests were conducted to evaluate the evaporation characteristics, water retention capacity, and CaCO3 distribution. Laboratory soil samples were further prepared to provide evidence related to underlying weathering mechanisms. The results show that MICP has a time‐dependent performance on drought mitigation. After MICP treatment, soil performs a remarkable evaporation suppression ability and the evaporation rate can decrease by 50%. This is attributed to the soluble salts which increase soil water retention capability and dense hard crust which inhibits water vapor migration into the atmosphere. However, the soluble salts and crust are sensitive to weathering thus leading to degradation of MICP. Suffering 16‐month weathering, the MICP‐induced CaCO3 decreases by more than 60%. The evaporation rate of soil increases with MICP rounds and cementation solution concentrations and can reach nearly two times of untreated soil. MICP‐treated field soil exhibits weaker water retention capacity than untreated soil because MICP alters soil microstructure which expands macropores and decreases volume of micropores. Connected macropores act as favorable evaporation channels and accelerate evaporation. To ensure MICP long‐term effects, periodical treatments are necessary. The most effective MICP treatment scheme is four to six treatment rounds and 1.0 M cementation solution. Key Points: The eco‐friendly technique‐microbial induced carbonate precipitation (MICP) performs the time‐dependence on long‐term drought mitigationMICP technique exhibits a remarkable evaporation reduction capacity which is attributed to the presence of soluble salts and hard crustThis study brings new insights into drought mitigation through a bio‐approach and shows the potential for in‐situ practice
- Subjects
EVAPORATIVE power; WATER shortages; SOILS; DIETARY supplements; SOLUBLE salts; DROUGHTS; DROUGHT forecasting
- Publication
Water Resources Research, 2024, Vol 60, Issue 7, p1
- ISSN
0043-1397
- Publication type
Article
- DOI
10.1029/2024WR037486