Porous irrigation pipe, with particular application to underground drip or continuous irrigation of densely packed crops, is prepared from particulate elastomer and thermoplastic binder containing controlled moisture content. A pelletizable mixture consists of a major portion of elastomer in crumb form, a slip agent, preferably a mineral such as talc, and a lubricant , such as a metal stearate. The elastomer is cis-1, 4-polyisoprene or synthetic homopolymers of butadiene or isoprene or their copolymers with minor amounts of 0.1 to 20% by weight of vinyl monomers, such as styrene, isobutylene or acrylonitrite. The elastomer is vulcanized. The rubber is ground into crumb particles no larger than those passing through a 10-mesh screen. The binder resin is a thermoplastic material capable of softening at a temperature below 300 F, so that pores will form during extrusion. Styrene polymers, including impact polystyrene copolymers, are useful as the resin, as are nylons, polyvinylchloride, polyphenylene oxide and polyphenylene sulfide polymers. The slip agent aids in extruding the rubber binder mixture. Finely divided materials other than talc can be utilized, such as clays, silicas, carbonates, or micas. The metal stearate lubricant can be selected from calcium, magnesium , or zinc stearates. (Cremmins-AEPCO)