| Mechanism of desiccation crack propagation in farmland soil under moistube irrigation |
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| DOI：10.7606/j.issn.1000-7601.2025.04.18 |
| Key Words: desiccation crack downward propagation moistube irrigation self\|adaptation pressure head |
| Author Name | Affiliation | | QI Wei | Department of Rural Water Management, Nanjing Hydraulic Research Institute of the Ministry of Water Resources, Ministry of Transport and National Energy Administration, Nanjing, Jiangsu 210029, China | | HE Yupu | Department of Rural Water Management, Nanjing Hydraulic Research Institute of the Ministry of Water Resources, Ministry of Transport and National Energy Administration, Nanjing, Jiangsu 210029, China | | WANG Shiyu | Department of Rural Water Management, Nanjing Hydraulic Research Institute of the Ministry of Water Resources, Ministry of Transport and National Energy Administration, Nanjing, Jiangsu 210029, China | | MAI Zijun | Department of Rural Water Management, Nanjing Hydraulic Research Institute of the Ministry of Water Resources, Ministry of Transport and National Energy Administration, Nanjing, Jiangsu 210029, China | | HUANG Mingyi | College of Agricultural Science and Engineering, Hohai University, Nanjing, Jiangsu 211100, China |
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| Abstract: |
| In order to investigate the mechanism of desiccation crack propagation in farmland under moistube irrigation, an experiment of moistube irrigation was conducted under simulated conditions of summer temperature, with treatment of three different pressure heads (10, 50, and 100 cm). During the experiment, the soil water content and infiltration rate were measured, and the superficial crack was captured by photographing. A three\|dimensional crack structure was obtained by the silica gel replacement\|scanning method. The development of crack propagation was analyzed by employing digital image processing technology. The results showed that under the influence of evaporation, the variation of soil water content with irrigation time could be roughly divided into a rapid decline stage within 100 h and a stable stage afterward in all treatments. The soil water content and the infiltration rate of moistube irrigation were fluctuating clearly with each individual day, verifying that the moistube irrigation had the capability of self\|adaptation. However, the capability was weakened with the increasing pressure head. The soil superficial crack ratio and length density first increased rapidly and then gradually stabilized with irrigation time, but the crack length density stabilized earlier than the crack ratio. The cracking degree was decreased continuously with soil depth, and most cracks propagated only within the topsoil of 4 cm. The downward propagation patterns of crack mainly included straight, inclined, “Bu” (Chinese character), and “Ren” (Chinese character) shaped. The pressure head of moistube irrigation had a significant effect on crack propagation. As the pressure head increased, the superficial crack ratio, length density, average width, and crack depth decreased. Compared with the treatment of 10 cm, the maximum depth of crack in the pressure head treatments of 50 cm and 100 cm respectively decreased by 19.4% and 55.6%, and the average maximum crack depth respectively decreased by 26.7% and 55.5%. The above results indicate that the pressure head has decisive effects on the adaptive adjustment of irrigation amount and the crack development, and should be reasonably modified according to specific conditions. |
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