Drip irrigation - an efficient system of water use
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CTA. 2007. Drip irrigation - an efficient system of water use. Rural Radio Resource Pack 07/1. Wageningen, The Netherlands: CTA.
Permanent link to this item: http://hdl.handle.net/10568/57471
A farmer explains his system of using drip irrigation with harvested rainwater to grow vegetable crops
Drip irrigation ? an efficient system of water use Cue: For those who earn a living from crop farming in dry areas, making the best use of water can make the difference between success and failure. One of the most efficient ways of irrigating crops is drip irrigation. The system works by spreading water onto a field through a number of narrow pipes, which are laid out on the soil surface parallel to the rows of crops. Tiny holes in the pipes allow drips of water to come out, and this seeps straight into the ground, quickly reaching the roots of the crop. Although it is a simple system, it allows farmers a lot of control; by adjusting the tap that feeds water into the pipes a farmer can provide just the right amount of water to the crop. It is also possible to add fertiliser, such as urea, to the water, a practice called fertigation. Drip irrigation systems can be supplied by pumped water, but farmers can also use gravity to power the system, by storing the water in a raised tank, which the pipes are connected to. South African vegetable farmer Mike Richter grows tomatoes, garlic, pumpkins and spinach on his drip irrigated plot; he gets the water by harvesting rainfall from the roof of his house and his farm buildings. Lucas Moloi visited his farm some 70 kilometres south of Johannesburg, to see the system in action. He asked Mike to firstly explain how it works. IN: ?First of all you have got to catch? OUT: ? is the best you can do.? DUR?N: 4?26? BACK ANNOUNCEMENT: Mike Richter, a small-scale vegetable farmer from South Africa. He was talking to Lucas Moloi, and the interview comes from a radio resource pack produced by CTA. Transcript Richter First of all you have got to catch as much water as possible from your gutters into tanks, and from there via piping, drip irrigation onto your vegetables. That is the most economical way of using water. That means you can open the tap whenever you need it in a dry season and you can close it when it is raining, you do not waste any water. Moloi So what could be expenses and labour involved in getting that system together? Richter Labour is actually more your own because everything you can do yourself. Plastic piping is much cheaper than steel piping in the olden years, and you can use a thin plastic which is very cheap actually and you can cut it with a knife and put it together with your hands, without getting anybody involved from outside. Moloi And now from your roof gutters to the tank, how does water get to the plants? Richter From there you have got to take it via the pipes to the drip irrigation. Or what you can do is, if you have got your tank high enough in the gutter, you can lead it to a secondary tank close to your vegetable garden. That means you can double the amount of water which you can store. And after that of course it is just a question of opening taps. Moloi For somebody who may not know this, what is drip irrigation? Richter Drip irrigation is actually a thin sort of pipe with small holes in it and it drips water, say a drop of water every three seconds or something like that. And you can always, according to the temperature or whatever, you can open the tap as much as you like. In a very hot day you will open it a little bit more, while in coolish weather you will have one drop in ten seconds or something like that. Moloi So is this type of system advisable for one to use at any size of a farm or is it advisable for only small-scale farms? Richter They use this on huge farms. I have been in the northern Transvaal where they use it on maize; it was about twenty hectares under drip irrigation. But of course there it is not rainwater, it is pumped from the ground and the pump is running continuously to supply the drip irrigation with the water. Moloi What could be the risks associated with this type of irrigation? Richter As far as the irrigation is concerned there is not very much risk. There are a few small problems and one is if you have got hard water when you use a bore hole, it might clog up your little holes, it would not drip properly anymore. That means you have got to apply a little bit more pressure to get the drip irrigation to work properly. But otherwise there is not really a risk. It is normal farming risks, that is insects, hail and what have you. Moloi So can a farmer use this type of drip irrigation on a slope where he has planted his or her vegetation? Richter Oh yes, it is exceptionally good on a slope because there is no running water. It goes into the ground as it drips on it, because you can just adjust it to drip slow enough so it does not run. Moloi So do you reap any benefits from this type of irrigation? Richter Oh yes, it is not labour intensive at all, you do not need anybody to move the pipes you just open a tap. And you can always calculate how much water you want and close the tap after so many minutes; then you have got the result which you want. Moloi So about soil type, can you use it despite the type of soil that you have planted your vegetation on? Richter Yes you can use it on just about every soil except when it is very very sandy. What you find then is that the water goes right down to the bottom without spreading out, and this is about the only soil I would not recommend drip irrigation. Moloi So can you still use the drip irrigation during any season? Richter Yes, yes winter and summer. Of course being a plastic pipe it would not burst in winter when it is very cold and in summer, while it has got water in it the sun would not damage it. But if it has not got water in it then it would not last very long. Moloi I do not know if there is something that you think I have left behind that you would like to add? Richter All I can tell you is that put as much organic stuff into the soil as possible because it contains a lot of water, it holds a lot of water, it does not damp out very easily, and it is very good for the soil and very good for drip irrigation. It is the best you can do. End of track.