Laboratory and numerical experiments were carried out to analyze the effect of soil texture on the emission characteristics of porous clay pipe used for subsurface irrigation. Results show that the emission rate of the pipe is linearly related to the applied hydraulic head in the open environment. With the pipe embedded in the soil, the emission rate becomes a function of the soil texture and the applied hydraulic head. For a given soil texture, as the applied hydraulic head in the pipe increases, the moisture content in the vicinity of the pipe becomes higher, and the effect of the capillary forces on the emission rate of the pipe decreases. Under saturated conditions in the vicinity of the pipe, the effect of capillary forces in the flow domain on the emission rate of the pipe is negligible. The study results are useful in designing the lateral spacing and installation depth of the pipelines, irrigation run time and length, and the hydraulic head required for proper operation of porous clay pipe based subsurface irrigation systems.
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