Experimental Study And Numerical Simulation On Ridge-furrow Irrigation Infiltration Of Spring Wheat In Arid Area

In order to understanding the water movement in ridge-furrow irrigation of springwheat in arid region, taken typical sandy clay loam and clay for an example in the Minqindesert oasis in downstream of Shiyang River Basin in Gansu province. Employedlaboratory experiment and numerical simulation studied on the law of infiltration intwo-dimensional and established infiltration model. The water movement was simulatedby using HYDRUS-2D mode at different bulk density, soil texture, initial water contentand ridge-furrow parameters, as well as evaluated of infiltration characteristics at thesefactors. The results will provide a theoretical basis for further study on the ridge culturefurrow technical parameters and improve irrigation quality under ridge culture furrowirrigation of spring wheat in arid area. The principal results are as follows:1. Using pressure membrane instrument to measure soil water retention curves, thehorizontal column infiltration method was used to measure the diffusivity for sandy clayloam and clay at different bulk density. The RETC software was employed to predict soilhydraulic parameters of van Genuchten model and the results was very well. The researchprovided a foundation for prediction of water movement in the soil.2. Laboratory experiments were conducted on a sand clay loam and clay at differentbulk density, and HYDRUS-2D software was used to simulate the soil watertwo-dimensional infiltration law under ridge-furrow irrigation of spring wheat. Comparedto observed and simulated, the results showed that the model can successfully simulateprocess of the water movement under ridge-furrow irrigation.3. For sandy clay loam and clay at different bulk density, the relationship betweenaccumulate flux and time were studied and developed a numerical model on the basic ofKostiakov equation, it provide some important foundation reference for irrigation volumeand irrigation efficient in ridge-furrow irrigation of spring wheat.4. Based on the simulation results, the soil conductive higher, the accumulation larger.The bulk density positively correlated with the accumulation flux. Initial water contenthas a little effect on accumulation flux. The ridge wide is less than50cm and less than 40cm on sandy clay loam and clay, respectively. Both bottom of ditch wide and thedepth of water table higher, positively correlated with the accumulate flux and wettedvolume larger. To improve irrigation quality, we should select depth of water table higherand bottom of ditch wide narrow in ridge-furrow irrigation system of spring wheat.