Changes

Since the plastic casing is essentially impervious, it must be perforated. The difficulty of standardizing the diameter and density of the perforations introduces another variable unto the system. The best configuration must be established by trial and error. This method has been used with success in Senegal. An interesting variation in Sri Lanka consists of a 50-cm long PVC pipe of standard °-inch diameter. The pipe ends

in an emitter, a block made from a 1:10 cement/ sand mixture. The design was found to be effective in enhancing the survival and growth rate of young fruit trees.

===Acknowledgements===

* Sijali, Isaya V. [http://www.samsamwater.com/library.php?serie=RELMA%20Technical%20Handbook%20Series DRIP IRRIGATION: Options for smallholder farmers in eastern and southern Africa.] RELMA, 2001.