中文摘要：

建立了重力式地下滴灌条件下的土壤水分运动模型,分析地下滴灌土壤水分入渗规律。对黄土高原不同分区的4种典型土壤、不同灌水技术要素条件下的地下滴灌土壤湿润体形态、滴孔处出流量及土壤土水势进行数值模拟得出：榆林紧砂土土壤导水率较大,向下渗漏过多,不适宜地下滴灌;安塞砂壤土、洛川中壤土、武功重壤土在相同灌水量下,供水压力与滴孔孔径对地下滴灌湿润体形态影响微弱,但对滴孔出流量有较大影响,因此在地下滴灌工程设计时,只需根据田块长度和渗水管损失设计孔径和供水压力,并采用较小供水压力,降低供水水池高度,减小工程量;对武功重壤土,孔径和供水压力较大时地下滴灌滴孔处土壤易饱和板结,宜采用较小的孔径和供水压力。

英文摘要：

Based on unsaturated soil water movement theory, a three-dimensional mathematical model was developed to describe water flow movement under gravity subsurface drip irrigation （SDI）. The effects of water supply pressure and dripper aperture on the soil wetting pattern, emitter charge and soil water potential with four typical soils from different subarea in Loess Plateau under gravity SDI were simulated and analyzed. The results indicate that the model can be used to analyze gravity SDI soil water infiltration characteristics and wetting pattern accurately. Gravity SDI is not suitable for Yulin area because of great deep leakage. Under the same irrigation quantity, pressure head and emitter diameter have slight effects on the wetting pattern but obvious effects on emitter effluent discharge in Ansai Sandy Loam, Luochuan Medium Loam and Wugong Heavy Loam. So the emitter aperture and water pressure can be decided only based on the field length and pipe infiltration loss for gravity SDI design. Meanwhile, it is necessary to adopt lower water pressure to reduce water supply pool height and the gravity SDI engineering investment. Especially for Wugong Heavy Loam, larger diameter dripper and higher water pressure will make the soil near drippers quick saturated and harden, therefore it should adopt the smaller diameter dripper and lower water pressure.