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| Water migration and distribution rules of micro-moistening irrigation under influence of cracks |
| QI Wei1*, HE Yupu1, JI Renjing1, MAI Zijun1, WANG Ce2, JIANG Xiaoxing3 |
| 1. State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, Jiangsu 210029, China; 2. College of Agricultural Science and Engineering, Hohai University, Nanjing, Jiangsu 211100, China; 3. Jiangning Hushu Street Water Authority, Nanjing, Jiangsu 211121, China |
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Abstract In order to study the influence of crack development on water migration and distribution characteristics of minimally moistening irrigation, an indoor soil box water infiltration test was conducted. Through artificial cracks, different crack spacing(6 and 8 cm)and crack depths(5, 10 and 15 cm)were set up. At the same time, the no crack treatment(CK)was used as a control to measure the changes in infiltration amount and morphological evolution of wet bodies and water distribution characteristics at the end of infiltration. The results show that cracks have basically no effect on the water infiltration rate of minimally moistening irrigation. The cumulative infiltration amount between treatments has a similar trend with the infiltration time, and the final cumulative infiltration amount is not significantly different. The cracks change the morphological evolution and water distribution characteristics of the moist body. After the wetting front reaches the crack area, under the influence of the capillary barrier effect of the crack, the horizontal movement of water is inhibited and the upward movement is strengthened. Eventually, the upper part of the wet body is approximately rectangular and the lower part is approximately elliptical, and the moisture distribution in the profile shows finger-like characte-ristics. The crack depth has a significant impact on the regularity of the wetting body, the upward migration distance of the wetting front, as well as the uniformity of water distribution after irrigation, while the impact of the crack spacing is not significant. Compared with CK, when the crack depth is 15 cm, the dispersion of the wet body increases by about 34.5%, the final upward migration distance of the wetting front increases by about 12.9%, and the moisture distribution uniformity decreases by about 27.5%. In the practical implementation of micro-moistening irrigation, it is essential to carefully manage the depth of cracks in the field to mitigate any negative consequences.
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Received: 12 October 2023
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