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| DOI： |
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| Influencing Factors of Negative Pressure Suction for Mud in Subsurface Drip Irrigation Emitter |
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GUO Pan, ZHANG Yijie, SONG Shiyu, YANG Haolin , YANG Zhenjie, XUE Xiang, YU Yang
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College of Mechanical and Electrical Engineering， Yunnan Agricultural University， Kunming 650201， China
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| Abstract: |
| In order to explore the influencing factors of negative pressure suction for mud of emitter under the SDI system, the influencing laws of the 6 factors, includory soil type, single irrigation amount, irrigation times, emitter type, water retaining agent and irrigation interval, were studied by contrast test. The results indicated that, ①negative pressure suction for mud and blocking condition were in existence both in the external and internal of water outlet of adjustable flow emitter. Three external water outlets were blocked with the largest ratio of 26.7%. The sediment distribution was mainly concentrated in the vicinity of the medial emitter outlets; very little part of the sediment even crossed the inner convex edge into the inner ring of the emitter. ②The ability of resisting negative pressure suction for mud of emitter in pressure compensating emitter was stronger than that of the flow adjustable emitter. No sediment was found in the external and internal water outlets of pressure compensating emitters, while some sediment was found in the external and internal water outlets of adjustable flow emitters. The negative pressure suction for mud was more prone to red soil than sand soil. The amount of internal sediment of emitter in red soil were 1.12～1.76 times than that of the amount in sand soil. ③The effect of irrigation methods (the amount of single irrigation, irrigation times, and irrigation interval) on negative pressure suction for mud of emitter was significant. The emitters with small internal single irrigation amount had a bigger amount of sediment. The amount of internal sediment in 170 mL single irrigation were 1.61～2.94 times than the amount in 250 mL. Irrigation times were directly proportional to the amount of negative pressure for mud. The amount of internal sediment for the 16 times of irrigation were 3.48～5.41 times than the amount in 8 times. Under the condition of the same irrigation times, the length of irrigation interval was directly proportional to the amount of negative pressure for mud. ④There was no negative pressure sucking mud in the emitter with water retaining agent. This paper provides a theoretical basis for the development of the irrigation device with the performance of good anti-negative-pressure-suction for mud of emitter. |
| Key words: SDI; negative pressure suction for mud; internal sediment amount; irrigation interval |
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