The area of southern Spain where I have my farm has be designated the only official desert in Europe. So how do we manage to grow anything apart from cactus and agaves? It is all to do with forward planning and organisation that goes back centuries.
One of the first things that you ask when looking to purchase agricultural land here is – has it got water? This may mean is there a well on the land, or do you have rights to access water from a spring, or does water arrive though one of the many small co-operatives that have been set up to provide water to a group of growers.
If the case is that there is water on the land it is usually extracted by a deep well being dug and then the water is pumped out. So you then want to know how deep the well is – the deeper the well the higher the potential costs of upkeep. How much water per second comes out of the well – this is an indication of how much water in total is likely to be down there – you do not want to be running dry in the middle of summer just when you need it the most. The last question then is about the quality of the water – in this area much of the land was once under the sea, so there is salt in varying strengths in the earth and the water. Plus being close to the sea the sea water can seep into natural underground water depoisits. Depending on what you wish to grow, a certain amount of salt is not necessarliy the end of the world. If I remember correctly tomatoes and citrus will tolerate up to 3% salt while olives will tolerate up to 7%.
The same questions apply if there is a spring. I have never ceased to be amazed at how the geology here will make a spring appear quite high up a mountain, while lower down it is totally arid.
For me my water arrives via the third option, a non profit making co-operative. Between us we own several springs, a desalination plant, have shares in the local reservoir and also shares in the pipelines that transport water from the wetter north. While to produce good water from the desalination plant is expensive there are two advantages to having it. One is that we can sell some of the water at a profit for household use, the proceeds of which then go back in the kitty to keep maintenance costs down, and the other is that as it is so clean it can be mixed with less good water from some of the wells enabling that to be used. In the old days the water would be sent down an “asequia” a channel built in stone with gates at intervals to guide the water into the desired direction. Some of these date back to the time when the Moors lived in spain and the system was indeed designed by them. Nowadays much of these channels have been replaced by plastic piping which loses a lot less water and delivers cleaner water. It is then stored in your water depoisit, either a “balsa” which is open to the elements, or an “aljibe” which is an underground tank.
I have the underground option and mine holds about 50 cubic metres which is 50,000 litres. It sounds like a lot, but when there are 400 lime trees, 20 olive trees, 20 orange and celmentine trees, another 40 trees of various fruits and nuts, plus vegetable and ornamental gardens all needing irrigation, it is not so much. Everything on the land is irrigated. Some plants need more water than others and at different times of the year, so you need the land dividing into different zones with a programmer to control the pump that can cope with the number of zones that you have. Then each zone can be manually subdivided by having taps on the feeder pipes that you can turn on and off. This is especially needed in the vegetable garden where there are times in the year where parts are not planted up. If all this sounds complicated, it is, at least the setting up of such a system is, but it is worth all the effort to have a system that works well for you and is flexible. As every piece of land that is cultivated here has an irrigation system the parts needed to set one up are very reasonable to buy, and there are plenty of firms that supply the systems, pumps and any advice needed.