移动滴灌系统土壤水分入渗试验与数值模拟  

Experiments and numerical simulations of soil water movement under mobile drip irrigation system

作　　者：张颢晖 严海军[1,2] 惠鑫 赵赫 王文涛 郭辉 ZHANG Haohui;YAN Haijun;HUI Xin;ZHAO He;WANG Wentao;GUO Hui(College of Water Resources and Civil Engineering,China Agricultural University,Beijing 100083,China;Engineering Research Center of Agricultural Water-Saving and Water Resources,Ministry of Education,Beijing 100083,China)

机构地区：[1]中国农业大学水利与土木工程学院,北京100083 [2]农业节水与水资源教育部工程研究中心,北京100083

出　　处：《农业工程学报》2023年第6期158-168,共11页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家牧草产业技术体系项目(CARS-34);河北省现代农业产业技术体系草业创新团队专项资金资助项目(HBCT2018160202);国家重点研发计划项目(2022YFD1300804)。

摘　　要：为减少大型喷灌机的喷灌水分蒸发漂移损失,将低压喷头改装成按适当间距布置的大流量压力补偿滴灌管,使大型喷灌机自走时拖拽滴灌管,实现边移动边滴灌。该移动滴灌系统融合了大型喷灌机与滴灌的技术优势,具有较高的节水潜力,研究其土壤水分入渗规律对于设计节水高效的灌溉系统具有重要意义。为确定移动滴灌管灌水后的土壤湿润体形状及土壤水分分布情况,该研究搭建了移动滴灌试验装置,设置30、40与50 mm 3种灌水深度进行移动滴灌土箱试验,同时利用HYDRUS-2D建立移动滴灌条件下的土壤水分运动数值模型。模拟与实测结果对比表明,所构建模型能较准确地反映移动滴灌的土壤水分运动规律,土壤剖面中的水分运动均遵循面源入渗模式,灌水后48 h土壤剖面含水率模拟值的标准均方根误差低于20%,各测点处含水率变化过程模拟的标准均方根误差值总体低于25%。利用所建模型分析了砂壤土、壤土与粉壤土3种不同的土壤质地,20、30与40mm3种不同的灌水深度以及0.050、0.075、0.100、0.125与0.150 cm3/cm35种不同的土壤初始含水率对移动滴灌条件下土壤水分入渗规律的影响。结果表明土壤质地对湿润峰运移距离与湿润体形状的影响较大,土壤砂性越强,湿润体横截面积越大,可以适应更大的滴灌管安装间距;对于供试砂壤土而言,增大灌水深度与土壤初始含水率,均可以提高湿润峰运移距离和灌水均匀性,但会加大深层渗漏风险。该研究结果对于大型喷灌机的移动滴灌系统设计运行具有重要参考价值。The low-pressure sprinklers have to be modified to replace the high flow rate pressure-compensating driplines at a certain spacing,in order to reduce the wind drift and evaporation loss of large-sized sprinkler irrigation machines.This mobile drip irrigation(MDI)system can be used to realize drip irrigation when moving,due to the self-propelled characteristics of the irrigation machines.This system can be utilized to combine the center pivot and drip irrigation,leading to a large coverage area of irrigation,high automation,low evaporation and drift losses.It is necessary to optimize the design parameters for the soil water infiltration under mobile drip irrigation.Therefore,laboratory experiments were carried out with the MDI test system.The mobile dripline was dragged and moved on the soil surface of a lysimeter.EC-5 soil moisture sensors were installed in the lysimeter to detect the dynamic change of the soil water contents at observation points.The irrigation depth was controlled to adjust the speed of the dripline.Three irrigation depths were set as 30,40,and 50 mm.A numerical model was established to improve the soil water infiltration and redistribution under MDI using HYDRUS-2D software.The comparison between the simulated and the measured data showed that the water movement in the soil profile under MDI was followed by the non-point source infiltration model,indicating the better agreement of the model with the measured.The NRMSE value of simulated water distribution in the soil profile was less than 20%,while the simulated water content change in the wetting body was generally lower than 25%,indicating the high accuracy of the model.HYDRUS-2D model was used to clarify the influences of three soil textures(sandy loam,loam,and silty loam),three irrigation depths(20,30,and 40 mm),and the five initial soil water contents(0.050,0.075,0.100,0.125,and 0.150 cm3/cm3)on the soil water movement under MDI.The HYDRUS-2D performed better to simulate the soil water distribution after irrigation under the MDI system.Th

关 键 词：土壤水分 入渗 灌溉 大型喷灌机 压力补偿滴头 数值模拟 HYDRUS-2D 

分 类 号：S275.6[农业科学—农业水土工程]