Gauteng Smallholder April 2016 | Page 21

IRRIGATION Water cannon is ideal for large fields and pasture, but requires a powerful pump and large volume of available water From page 17 components along the way. both the pump and the number of delivery heads you wish to use, ensuring sufficient volume of water is available at the point of delivery at sufficient pressure to achieve the desired result. Unfortunately (and certainly on older plots) irrigation systems tend to be a mishmash of pipe diameters, with lengths of 32mm diameter LDPE pipe connected to bits of 40mm pipe and holes being repaired by connector pieces along the way. All of these differences of diameter will mean that the volume of water available at the end is limited by the smallest diameter of the Typically, a 32mm plastic pipe fitting (eg elbow or straight connector) will have an internal diameter four or five millimetres less. Thus, it doesn't matter if there are bits of 40mm or 50mm pipe in the set-up; the volume of water at the end will be governed by the 32mm fittings. K The nature of your soil. Heavy, clayey soils retain moisture better that light sandy soils and thus require less water to achieve saturation. K How much mulch you spread atop your beds to prevent evaporation. Travelling irrigator uses the pressure of the water to turn the wheels. 19 www.sasmallholder.co.za