| 齐伟,和玉璞,王诗雨,麦紫君,黄明逸.微润灌下农田土壤干缩裂隙发育机理[J].干旱地区农业研究,2025,(4):173~183 |
| 微润灌下农田土壤干缩裂隙发育机理 |
| 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 |
| 中文关键词: 干缩裂隙 纵向发育 微润灌 自适应 压力水头 |
| 英文关键词:desiccation crack downward propagation moistube irrigation self\|adaptation pressure head |
| 基金项目:国家自然科学基金（52409064，52309044）；江苏省自然科学基金（BK20230126）；中央级公益性科研院所基本科研业务费专项资金项目（Y923001）；江苏省水利科技项目（2023030） |
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| 中文摘要: |
| 为探明微润灌下农田土壤干缩裂隙发育规律，开展模拟夏季气温条件的微润灌土箱试验，设置3种压力水头处理（10、50、100 cm），测定土壤含水率和水分入渗变化情况，拍照记录表层裂隙演化过程，并采用硅胶置换扫描法获取裂隙三维结构，结合图像处理技术对裂隙发育情况进行分析。结果表明：在蒸发影响下，各处理土壤含水率均表现为先快速下降然后在约100 h趋于稳定的两阶段变化特征。土壤含水率和微润灌入渗率均有明显的日内波动特征，验证了微润灌具有自适应调节能力，但调节能力随压力水头的增加而减弱。各处理土壤表层裂隙面积率和长度密度变化均表现为先快速上升后趋于稳定，但裂隙长度密度的稳定时间早于裂隙面积率。裂隙发育程度随土壤深度增加不断降低，大部分裂隙仅在表层4 cm深度内发育。根据走向特点，土壤裂隙纵向发育走向大致可分为竖直、倾斜、“卜”字形和“人”字形四种情况。微润灌压力水头对裂隙发育有显著影响，表层裂隙面积率、长度密度、平均宽度和裂隙深度均随微润灌压力水头的增大而减小。相比10 cm水头处理，50 cm和100 cm水头处理下裂隙最大深度分别减小19.4%和55.6%，平均最大深度分别减小26.7%和55.5%。综上，微润灌压力水头对灌溉水量自适应调节和土壤裂隙发育有决定性作用，在实际应用时应根据具体情况合理调整压力水头。 |
| 英文摘要: |
| 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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