点源滴灌滴头流量与湿润体关系研究

滴头流量影响土壤湿润体的大小和形状，从而对作物根系生长也有影响。工程设计中应根据滴头流量与土壤湿润体的关系确定滴头流量的设计依据。该文以等效圆柱湿润体模型为基础，建立了点源滴灌滴头流量的数学模型，针对模型中各因子随滴头流量的变化过程进行实验分析，确定影响点源滴灌滴头流量设计的主要因素。实验所用土壤为重壤土、中壤土、砂壤土，滴头流量分别为1、2、3、4 L/h。结果表明：滴头流量对湿润锋水平运移的影响比对垂直运移的影响大；地表积水区的变化对土壤湿润锋水平运移有控制作用。点源滴灌设计中，除了土壤入渗特性外，设计湿润比(或湿润直径)也是选择滴头流量的重要依据。

Relationships between dripper discharge and soil wetting pattern for drip irrigation

With the effect on soil wetting pattern, the dripper discharge has influence on crop roots development. In the design of drip irrigation system, the dripper discharge should be reasonably determined according to the relationships between dripper discharge and soil wetting pattern. Based on the equivalent cylindrical pattern of soil wetting front, the model of dripper discharge was developed mathematically, and the change of each factor with the dripper discharge was analyzed to determine the main influential factors of dripper discharge design for drip irrigation system. The experimental soils were clay soil, loam clay and sandy soil; while the experimental dripper discharges were 1, 2, 3 and 4 L/h, respectively. The results indicate that dripper discharge has more influence on the horizontal distance of soil wetting front than that on the vertical one. Soil saturated pond could control the horizontal distance of soil wetting front. In the design of the drip irrigation system, the dripper discharge should be determined on the designed soil wetting proportion (or wetting diameter), except for the soil infiltration characteristics.