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While drip irrigation is a very good technology in the right hands, experience with small holder farmers in a number of countries in southern and eastern Africa is not encouraging. If they are for use by entrepreneurial well educated farmers in a water scarce area then it will probably work. Drip irrigation can be done on two basic scales, a "conventional" system involving an installation over a relatively large area. This is a high tech approach to irrigation involving pumps, sophisticated filtration equipment and fertigation with liquid fertiliser. It is appropriate for commercial scale farms. Some attempts have been made to use these schemes with groups of smallholder farmers but the capital costs are high and the operation costs and maintenance requirements make them more prone to failure than other group managed schemes.

On a more individual level drip kits are available are available at various scales up yo around 500m2. These are often promoted by NGOs as a good technology for poor smallholder farmers. Again in the right circumstances they can work but often don't. The cost is still relatively high as they require a header tank, conveyance pipes and drip lines. In most circumstances they also need some form of pump to get the water from a nearby source into the header tank. I have seen a set up where a farmer was expected to collect water from a river, carry it uphill past his crops in a bucket and then lift the bucket over his head to fill the tank. Of course it was not long before he decided it was easier to pour the water directly onto the crops. I have also heard of farmers being unsatisfied with the slightly damp patch on the ground and feel that the plants are not getting enough water. So after watering using the drip kit they come along and add further water with a watering can. This may have come from work done by Doug Merrey at IWMI.

Apart from the high capital cost, some drip kits have a limited life-span. The cheaper ones with lay-flat plastic dripper pipes are easily damaged and being chewed by rats is a common problem. More robust pipes exist but the cost goes up. I have heard of a life-span of 5 years or less so if the technology is going to be introduced in an area a supply chain of spare parts at affordable cost must also be there.

The water may emerge from a simple hole in the pipe or a more complex emitter. These are prone to blockage with silt if the water is not properly filtered or salts precipitating from brackish water which adds another maintenance requirement.

Micro-jet irrigation uses what are in effect mini sprinklers. They have similar advantages (water saving) and disadvantages (see above) to drip irrigation and probably require slightly higher water pressure.