Wireless sensors and GPS-guided irrigation are helping early adopters cut use. But there are barriers to widespread use.
The greatest adoption of smarter irrigation technology is in center pivot irrigation, Texas A&M's Fipps says. This is the technique that creates those endless circles of crops you can see when flying over farm country. About a quarter mile of irrigation piping on wheels swings automatically around the field, spraying water constantly as it passes over field crops such as corn or soybeans.
In just the past few years, farmers have started mapping their fields based on water needs using GPS, which lets them mark areas that don't need watering, such as a bog, or areas that need less watering because of soil conditions. Since it's adding intelligence to an existing automated system's control panel, it's easy to integrate into existing operations, Fipps says. The GPS controllers also can be used to improve "chemigation," when chemicals are applied along with water.
There's also hope that the Web can help promote data sharing--data that's been available since the mid-1990s, but that's far from universally used.
The most basic calculation in irrigation comes down to this: Farmers must water enough to replace what's sucked out of the soil--either what evaporates into the air or is gulped up by plants. That calculation's called evapotranspiration, or ET, and it's based on temperature, rain, sunshine, wind, humidity, and more. There are myriad regional efforts to collect that data (generally on the county level), calculate ET information for those areas, and get the information to farmers so they can use it to adjust irrigation.
Fipps runs a network in Texas that provides this data on a Web site that lets farmers do custom calculations, entering when they planted crops and calculate water needs based on that and ET conditions. The system then e-mails each farmer with personalized suggestions for watering. It doesn't take sophisticated irrigation control systems to implement ET, Fipps says, which is why water conservation advocates promote it so widely.
Still, he acknowledges "a slow increase" in the number of farmers using ET data to estimate how much water their plants need, rather than just watering on a set schedule. Making ET data more accessible by the Web and e-mail isn't enough. "I wish something like a technology was going to be the answer," Fipps says. "Technologies help and will make a big impact, but it's the individual that turns water off or runs it too long."
It often takes a crisis--economic or political turmoil, or both--to drive change. Water shortages in California and the rest of the West are creating those conditions, which is partly why one startup picked that region to launch a software business that helps farmers manage irrigation using data like the kind generated by wireless moisture sensors.
Farmers use less water by monitoring soil and weather conditions, giving plants just the water they need
GPS-directed irrigation adjusts to varying water needs across a single field
Farmers get higher yields and use less water, using all these tools
Water savings aren't always enough for payback on high-tech irrigation
Systems must be customized to a farm, which takes time and expertise
Unpredictable water supplies make investment risky and planning difficult