为了研究滴头流量和设计湿润比对土壤水分运移规律及湿润体特性的影响，前期利用粘壤土进行试验研究，然后依据非饱和土壤水动力学理论和滴灌条件下土壤水分运移特征，建立了土壤水分运动模型，利用HY-DRUS－3D对不同湿润比下滴灌土壤入渗模型进行求解。通过所建模型，对11个观测点的模拟结果与实测结果进行了对比，得出灌水结束时各观测点模拟与实测含水率的相对误差均小于10％，实测与模拟湿润比的相对误差为4．75％～11．78％。利用所建模型对不同情景下湿润体运移规律进行了模拟，获得了湿润体特征变化规律：滴头流量主要影响水平湿润锋的运移距离，而设计湿润比对垂直湿润锋运移距离的影响较大；滴头流量相同时，设计湿润比越大，湿润体内平均含水率越大，高含水区（含水率＞0．410 cm3· cm－3）半径也越大；设计湿润比相同时，湿润体内含水率高于0．410 cm3· cm－3的湿润半径随流量增大而增大。%Designed wetted percentage and dripper discharge are two important parameters in the design of drip irri-gation system ,affecting the size of wetted body and growth status of plant .With the aim of elucidating the influence of dripper discharge and thereby designing wetted percentage according to soil moisture migration and wetting soil character-istic ,this paper based on the theory of unsaturated dynamics and the characteristics of soil moisture transfer under drip ir-rigation ,and established a model of soil water movement ,HYDRUS-3D software ,to solve the soil infiltration model un-der different wetted soil percentage .The contrast of measured and simulated values showed that at the end of irrigation , the relative error between simulated and measured values of each observation point were less than 10% ,and those for wetted soil percentage were 4 .75% ~11 .78% .By simulating the wetted soil moisture migration under different condition using the established model ,we obtained the rule of wetting body characteristics .Dripper discharge mainly affected the migration distance in horizontal direction , design wetted soil percentage had a greater influence on vertical direction . When the dipper discharge is the same ,the larger the design wetted soil percentage ,the greater the average moisture content in wetted body and the bigger radius of high water zone (water content>0 .410 cm3 ·cm-3 ) .When the design wetted percentage was the same ,the radius of high water cut in wetted body increased as the dripper discharge increased .
展开▼
