Effects Of Irrigation Quota And Dripper Discharge With Brackish Water Irrigation On Soil Water And Salt Distribution And Watermelon Yield In Gravel-sand Mulching Field

Reasonable use of brackish water is an important way to alleviate water resource shortages,and regulating distribution of water and salinity is key to its rational use.Drip irrigation is an effective method of utilizing brackish water,and irrigation quota and emitter discharge rate are key technical parameters that affect water salinity distribution.In order to increase the yield of watermelons in gravel-sand mulched field through the use of saline water drip irrigation,suitable parameters need to be determined.Therefore,this study conducted a two-year field experiment with emitter discharge rates of 2L/h,3L/h,and 4L/h,and irrigation quotas of 90m3/hm2,112m3/hm2,224m3/hm2,and 336m3/hm2.The study investigated the impact of irrigation quotas and emitter discharge rates on the distribution of soil salinity in gravel-sand mulched field,as well as the effects on watermelon growth,yield,quality,and water consumption patterns.This research provides theoretical support and technical guidance for selecting suitable saline water drip irrigation parameters in gravel-sand mulched field.The main research findings are as follows:(1)Soil moisture range increases with the increase of irrigation quota.The vertical movement distance of soil water decreases with the increase of emitter discharge rate,while the horizontal movement distance increases.Under the condition of an irrigation quota of 90m3/hm2,the soil moisture depth of 2L/h emitter discharge rate is 80cm,3L/h is 60cm,and 4L/h is 40-50cm.Under the same emitter discharge rate,soil moisture depth increases with the increase of irrigation quota.Watermelon water consumption decreases as the emitter discharge rate increases under the irrigation quotas of 90m3/hm2 and 112m3/hm2.However,under the irrigation quota of 224m3/hm2,watermelon water consumption first decreases and then increases with the increase of emitter discharge rate.Under the irrigation quota of 336m3/hm2,watermelon water consumption first increases and then decreases with the increase of emitter discharge rate.Crop water consumption increases with the increase of irrigation quota.(2)With an emitter discharge rate of 2L/h,soil salinity leaching efficiency improves with the increase of irrigation quota,and soil salinity decreases with the increase of irrigation quota.When the emitter discharge rate is 3L/h and 4L/h,soil salinity increases with the increase of irrigation quota.Under the irrigation quotas of 90m3/hm2 and 112m3/hm2,the salt content of soil layer 0-100cm in the membrane area decreases with the increase of emitter discharge rate.However,when the irrigation quotas are 224m3/hm2 and 336m3/hm2,soil salinity increases with the increase of emitter discharge rate.(3)From the perspective of growth indicators such as the main vine length and stem thickness of watermelon,4L/h emitter discharge rate is better under irrigation quotas of 90m3/hm2 and 112m3/hm2,while 3L/h emitter discharge rate is better under the irrigation quota of 224m3/hm2 and 336m3/hm2.In terms of watermelon yield,4L/h emitter discharge rate is better under irrigation quotas of 90m3/hm2 and 112m3/hm2,while 3L/h emitter discharge rate is better under irrigation quotas of 224m3/hm2 and 336m3/hm2.Watermelon yield increases with the increase of irrigation quota,but first increases and then decreases with the increase of emitter discharge rate.Irrigation quotas and emitter discharge rates have a significant interactive effect on watermelon yield and quality.(4)Topsis analysis shows that the treatment with an irrigation quota of 224m3/hm2 and an emitter discharge rate of 3L/h performed the best,with a yield of 49.07t/hm2,which is a 42%increase compared to the treatment of 224m3/hm2 and 2L/h emitter discharge rate,and a 78%increase compared to the treatment of 112m3/hm2 and 2L/h emitter discharge rate with the lowest yield.In summary,the suitable irrigation quota for saline water drip irrigation in gravel-sand mulched field for watermelon is 224m3/hm2,and the emitter discharge rate is 3L/h.