| Shortage in water resource has been the common issues concerned bywhole world.In order to save water resource more effectively so as to grow outmore food by using the limited water resource, and meanwhile, facing with thegrowing problem of water and soil erosion and land desertification innorthwestern regions of China, a highly efficient water-saving irrigation is badlyneeded to alleviate the worsening crisis. This paper presents a new Self-suctionMicro-irrigation. The research results are obtained as following: detecting theproduction of self-suction micro-irrigation, depth analysis of self-suctionmicro-irrigation’s influencing factors, building self-suction micro-irrigationsystem in field to irrigate cotton, and coming up with some problems exist in thesystem and research direction of future.There are induction period exist in effluent of moistube, and the inductiontime is21hours. After this, the relationship between accumulated seepage andtime is linear. As time becomes increased, moistube’s time interval flow tends toincrease, and when the flow becomes stable, it will go up and down dependingon average of flow over time, which is similar to the daily variation of airtemperature. Giving the fitting between flow and pressure, obtains the curvilinear equation:Q93.00H0.81. The deviation factors caused by moistubeare all within9%, and experiment’s materials reach a good grade.The flow of1m and2m hydraulic heads correlates significant with watertemperature in0.01level, and the two cases show positive correlation. Whenwater temperature rises, the flow increases, and when water temperature reduces,the flow decreases. The relationship between moistube’s flow and watertemperature is linear. When temperature changes1℃, the variation of flow:1mwater pressure corresponds5.89ml, and2m water pressure corresponds9.26ml,which indicates that the greater hydraulic head, the larger impact thetemperature on flow.The relationship between moistube’s pressure and flow is exponentialrelationship, and flow index is bigger than0.5. Different time of observation’swetting front shape is similar to a circle used by micro-irrigation zone as thecenter, and the wetting front that lay along the direction of moistube is basicallyparallel to moistube. With the prolonged time of irrigation and the increase ofinfiltration capacity, different directions’ wetting front shapes in wetting bodyare ever-expanding, but the speed of extension is slow down gradually. After acertain time of watering, the speed of wetting front’s extension slows downobviously, and finally, it almost doesn’t expand any more. At the same time ofirrigation, wetting body’s wetting radius in both vertically up and verticallydown is almost equal to wetting radius in horizontal direction. The varyingtendency among Wetting front X、Z±、and cumulative infiltration expressed by power function, which has a high correlation index above0.90.In the field experiment, the infiltration capacity moistube is233.9ml/h/m in5m effective head. As irrigation continues, flow presents a gradually decreasesituation because of the chemical blockage in moistube. About one month, thedecrease of flow reach a stable numerical value, and the flow of moistube is169.3ml/h/m. The flow of moistube’s decay rate is27.6%, and it will not decaylater. Soil moisture content is almost a fixed amount that is60%of soil waterrate. In the case of not serious blocking of micro-irrigation, the volume ofirrigation water can basically meet the cotton growing requirement. Comparedthe cotton planted by micro-irrigation to trickle irrigation, irrigation waterconsumption saves42.67m3/mu, the yield increases100.4kg/mu, and the wateruse efficiency reaches1.25kg/m3.Nowadays, the shortage of water becomes increasingly severe so that thereexists a broad application prospect and practical value of micro-irrigationtechnology. |
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