Yaohui Cai, Pute Wu, Delan Zhu, Lin Zhang, Junying Chen, Xiao Zhao

　　College of Water Resources and Architecture Engineering, Northwest A&F University, Yangling, Shaanxi 712100, PR China

　　Subsurface irrigation has been realized by burying pots, pitchers and subsurface porous pipe, but the present preparation process of porous ceramics could not meet the performance requirements of subsurface irrigation emitters. The existing preparation process of porous ceramic emitter is expensive and complex. In this study, a new preparation process of porous ceramics emitter with good performance and low cost was proposed. And then the porous ceramic emitters were buried in the soil, an experiment was conducted in the soil bin with three design discharges (0.72 L/h, 1.87 L/h, 4.40 L/h). The variation of emitter discharge and soil water content around the emitter in different treatment was analyzed. Meanwhile, the seepage characteristics of porous ceramic irrigation emitters were discussed. The results show that the sintering temperature and the contents of chalk in the green body are two key factors influencing the properties of porous ceramics. the discharge was a positive relationship with sintering temperature. Emitter discharge in the soil decreased gradually with time and finally stabilized. On the contrary, the soil water content around the emitter increased rapidly, tending to approach saturation. Design discharge had a significant effect on the emitter discharge in the soil. Soil water content around emitters had an appreciable negative effect on emitter discharge in the soil. There is a feedback regulation relationship between water content and emitter discharge. If a porous ceramic emitter with an appropriate design discharge, which working pressure head is extremely low or zero, the soil water content can be automatically controlled and the emitter would take the initiative to irrigation.