Experimental Research On Water Consumption And Irrigation System Of The Cotton Under High-frequency Drip Irrigation Mulched With Plastic Films

The area of drip irrigation for the cotton membrane of Xin Jiang relative to the area for planting cotton, there is great potential and space for development by means of the application and promotion for cotton drip irrigation technology. Water demand regulation of cotton by drip irrigation under mulch is the key basis for making irrigation institution and decision, however, lacking of relative Kc value lead to the unscientific method for making institution and decision of crop irrigation. With the research and spread of the automated irrigation, the appropriate high-frequency irrigation can make the crop production reach the maximum, however, the high frequency of irrigation system is still blank, so in this paper, studying the crop coefficient Kc value of the high-frequency irrigation system can provide the theoretical basis for the theory of crop needing water, at the same time, studying the high-frequency irrigation system can also provide the basis for the decision-making of crop fully irrigated automatically.In this paper, irrigating the cotton using different frequency of irrigation under the condition of drip irrigation for the membrane, in order to study the corresponding changing process of wasting water in the field, the requirements of the water for the crop, crop coefficients, cotton physiological indicators and irrigation system. Through the field experiments and theoretical analysis, the following preliminary conclusions can be drawn:(1) The total water consumed during the whole growing period and the intensity of the consumed water can be gotten from the water balance equation. During the growing period, the amount of the consumed water for the cotton increased until at the flower stage which could reach 10 mm/d, later on, it decreased gradually. With the increasing frequency of irrigation during the flower stage, water consumption for cotton also increased, and the amount of the consumed water in the first and second condition was more than it in the third and comparison model at the same growing period by 1.4 ~1.9 mm/d.When calculating the water demand of the referenced crop with the Penman-Monteith formula, based on different climate data (sunshine hours and measured solar radiation) and calculated in different ways, then the results are close, which provide the new thought for the research on the water demand of the referenced crop. The results getting by calculated were similar, the maximum difference was 1.5mm/d, the difference of average values was 0.2 mm/d in whole growth period﹝the value was more calculated by sunshine hours﹞.The crop coefficient throughout the growing period of cotton increased and then decreased , arriving at the peak until the flower stage, keeping stable for a shorter time, and during this period, has a few change, while the crop coefficient in the fruit stage gradually dropped with a great extent.(2) Along the growth of cotton, the physiological indicators had obvious effected by the irrigation frequency. With the increasing frequency of irrigation during the flower stage, the length of the main root of cotton heightened, leaf area and leaf area index increased, and the height of stem grown, while there was little impact on the wide of the stem.(3) The three yields of cotton which had dealt with high-frequency irrigation are 4545 kg/hm2, 4533 kg/hm2, 4288 kg/hm2 respectively, that is increased 12.4 %, 12.2 % and 6.1 % compared with the 4043 kg/hm2 which is the yield of comparison model, so the appropriate high-frequency drip irrigation can increase cotton production during the flower stage. The amount of high-frequency drip irrigation under mulch could be 3590 m3/hm2, and this technology should be used in the flower stage of cotton..