Pivot irrigation in Georgia

In Southwest Georgia there are more than 6,000 center pivots used to water peanuts, cotton and corn. Farmers have control over how much water the irrigation nozzles spray as they pass over fields. Small fields can vary in topography and soil types, with some places wetter or drier than other places in the same field.

VRI technology

The concept is simple: apply water when and where crops need it. Don't apply it where they don't. VRI technology uses computer maps, global positioning systems, soil sensors and software to control where and how much water the nozzles on a center pivot spray on crops.

Growers want to irrigate more precisely, but don't have the time or level with higher-tech gadgets. The more time-consuming technology steps have been eliminated to make the system easier for farmers to use.

Instead of having to create computer maps of fields, this system has a simple "push-button" feature. A farmer can start the center pivot over a field. When it gets to a location he doesn't want to apply water, the farmer pushes the button to train the system not to water that area. Once the system passes this area, he pushes the button again to resume watering only the crop. This can be done in as many as 8 locations in the same field.

The water efficiency of VRI has been tested on farms in Georgia and found it can reduce the water use in a field by as much as 15% annually without sacrificing crop yield.

Water for farming

Most people may drink only two litres of water a day, but they consume about 3,000 if the water that goes into their food is taken into account. The rich gulp down far more, since they tend to eat more meat, which takes far more water to produce than grains.

So as the world’s population grows and incomes rise, farms will (if they use today’s methods) need a great deal more water to keep everyone fed: 2,000 more cubic kilometres a year by 2030, or over a quarter more than they use today.

Yet in many farming regions, water is scarce and likely to get scarcer as global warming worsens. The world is facing not so much a food crisis as a water crisis.

The solution, is more efficient use of water (Pivot Irrigation Systems) or, "more crop per drop”. Some 1.2 billion people, about a fifth of the world’s population, live in places that are short of water. Farming accounts for roughly 70% of human water consumption.

So when water starts to run out, as is happening in northern China, southern Spain and the western United States, among other places, farming tends to offer the best potential for thrift. But governments, whether to win votes or to protect the poor, rarely charge farmers a market price for water. So they are usually more wasteful than other consumers—even though the value they create from the water is often less than households or industry would be willing to pay for it.