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| Relationship between subsurface seepage pipe pressure and soil water movement at tea root zone |
| ZHANG Hengnian1, ZHANG Chuan1*, YAN Haofang2, HU Yongguang1, ZHAO Baoshan2, LI Xinyu1, XING Deke1 |
| 1. School of Agricultural Equipment Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China; 2. National Research Center of Pumps, Jiangsu University, Zhenjiang, Jiangsu 212013, China |
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Abstract In order to investigate the relationship between the pressure at both ends of a subsurface seepage pipe and the soil water movement under sinfiltration irrigation, experiments were carried out by testing different irrigation flow rates and irrigation durations. By continuously monitoring the changes in soil moisture content in the root zones of tea trees(30 cm in the vertical direction and 30 cm in the horizontal direction of the soil moisture monitoring profile)and the pressure at both ends of the subsurface seepage pipe, the soil water movement under different pressures at both ends of the subsurface seepage pipe was examined. The results show that soil water content before irrigation influences the infiltration capacity, and impacts the direction of soil water movement. The cumulative pressure at both ends of the subsurface seepage pipe shows a linear relationship with irrigation duration. The slope of the cumulative pressure curve changes suddenly when the soil moisture content reaches the field capacity at the tea root zone. It is found that the duration of irrigation at the time of abrupt change in slope of the cumulative pressure curve can be used as a critical value for controlling the full irrigation(100% field capacity), thereby avoiding the loss of soil water in deep percolation. The study provides a reasonable reference method for rational control of irrigation duration.
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Received: 13 August 2018
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