| Xinjiang is located in arid area, where no irrigation means any agriculture due to rare rain and arid climate. Therefore irrigation is essential for developing agriculture. However, shortage of water seriously restricts irrigation. For that reason, developing modern water saving irrigation is the fundamental way for Xinjiang agriculture. So recently in Xinjiang drip irrigation technology gets popularization and application in large area. Most area irrigation water mainly depends on rain runoff and melt-water and so on which is surface water with high sediment. The most disadvantages of that can cause serious clogging of emitter. It is not only affect irrigation quality, but also interrupt the normal operation of the irrigation system. Therefore how to reduce and relieve the clogging of emitter becomes the key problem at present. The paper simulated the river water in flood season in Xinjiang as test water to irrigate. By field and lab experiment, clogging, outflow of emitters, deposition in lumen and channel and irrigation uniformity were studied under five water quality conditions with four kinds drip tapes which commonly used in field drip irrigation under mulch in Xinjiang. The main conclusions are listed as follow:(1)Under the same water quality, the number of clogging emitters of large flow path is more than small ones. In S80 water quality, the number of clogging emitter of four kinds drip tapes is the most, and the clogging of small flow path is more seriously, therefore small ones do not fit to use in the S80 water quality; In S100,S120,D75 and D120 water quality, four kinds drip tapes with different level of clogging can be applied in production, but should base on the number of irrigation during the growing period to select suitable crops. Generally, small flow path emitter is suitable for less irrigation times crops, thus lager ones fit for more irrigation times crops such as cotton.(2)Under five water quality, sand sediment volume in the lumen of four kinds drip tapes gradually increases along the capillary from the head to the end; and sand sediment volume at the same length of the capillary of large flow path emitter is less than small ones; The value of sediment D50 in different position of the lumen of lager flow path emitter is later than small ones; Under different water quality, the position of the max D50 of deposition sand in different lumen is the same as the position where is easy to be clogged.(3)Sand diameter<0.05mm can pass the channel, but sand diameter at the range of 0.05-0.1mm is apt to depositing in the lumen and channel of drip tape, furthermore it causes emitter clogging. Therefore, during irrigation period without washing for large flow path emitters which irrigate about 10 times don't occur serious clogging, its suitable water quality is that sand diameter is less than 0.05 mm, and after treatment of 120 mesh filter sand content is no more than 2.4 kg/m~3; In order to satisfy with irrigation demand of cotton, small flow path emitter suitable water quality is: sand diameter<0.05 mm, after treatment of 120 mesh filter sand content about 1.5 kg/m~3.(4)In S80 water quality,flushing the capillary after every two irrigation times is helpful to improve anti-clogging of drip tape, especially for small ones. With the increasing of the irrigation times, discharge and irrigation uniformity of small flow path emitters shows little change. For large ones the flushing frequency can be decreased, due to their better anti-clogging. In regular flushing conditions, suitable water quality of large flow path emitters is similar with that under no flushing conditions, thus for small ones suitable water quality is:sand diameter<0.05 mm,after treatment of 120 mesh filter sand content about 2 kg/m~3. |
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