The farmers in the region employ center-pivot irrigation systems, which pump water from underground and spray it on crops in a circular pattern from rolling metal tubes fed from a central pivot. The water conservation partnership focused on this technology specifically. Next, they helped some local farmers install, demonstrate and prove so-called variable-rate irrigation, which instead of simply dumping water on a given field equally at every point can vary the application from place to place. "Last year that system at my farm, we saved two [million] to three million gallons [7.5 million to 11.3 million liters] of water by having that system cut off over wasteland," Tabb notes. "Do that over 500 systems and see how much water we can save."

Variable-rate irrigation systems save 15 percent of water use on average, the equivalent of roughly two irrigations a year. As a result, the technology has begun to spread to other farms in Georgia and nine other states, and it is now being offered as an option for new center-pivot irrigation systems worldwide. "As the price comes down, [variable-rate irrigation] is going to be common. Why water places that you don't need to water?" Reckford asks. "There are roughly 250,000 center pivots in the world so there are a lot of systems where that improvement could occur."

But variable-rate irrigation currently relies on a static map of a given field, water here but not there in an unvarying pattern and with little consideration of soil type or field condition. That's where the University of Georgia's new sensor probes, which allow farmers to monitor soil moisture in real time, come in. "The shape of the [field] map is changing as plant conditions change," explains U.G.A. agricultural engineer George Vellidis, who designed the monitoring system.

And, instead of farmers having to visit each field and check the data, the probes will relay the information to their home computers, where IBM's Cognos software will sift the data to find the relevant bits and determine where and when to water. "By managing every drop of water within the Flint River Basin, you're better meeting the needs of people and the environment," says Mark Werbeck, the IBM account executive for the project.

The project will spend $1.1 million on probes and software for 10 fields to test their efficacy over the next two years—one of the first applications of sensor technology and data management to agriculture. In the future sensors to measure nutrients or soil acidity could also be added to the probes, and Cognos software could integrate global positioning system data from tractors and fuel usage, along with the type and amount of seed applied. Regardless, the water data alone should cut down on farmer costs: even without the soil probes, the partnership's variable-rate irrigation and other technologies can already save as much as 57 billion liters of water per year. "Dumping water on the crop is the most expensive thing we do," Tabb says. "Water isn't free, given the price of electricity, oil and the equipment itself."

The new technology won't just help farmers in the 265,000-hectare Lower Flint River Basin, it will also help all those who rely on the water from the Floridian Aquifer—from the human residents of Savannah and Orlando to the alligator snapping turtle that inhabits the region's slow-moving rivers, lakes and bayous. The Lower Flint River Basin is home to the largest concentration of amphibian and reptile species in the entire U.S., many of which are rare, threatened or endangered. When farmers like Tabb conserve water, more of it flows within the region’s waterways. "There is a very strong ethic of conservation built deep into these men," Reckford notes. "They grew up on these rivers and streams. They love them. Having the tools to preserve them is something they support and are willing to take a risk to adopt."

3 Comments

1. 1. ErnestPayne 05:33 PM 5/23/12

   A most worthwhile endevor. A case where subsidies to encourage this would pay large dividends.

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2. 2. ENVME 12:19 PM 5/25/12

   Precision use of water whether it be for Agricultural, golf course or parks and yards is nothing new. A wide variety of soil moisture monitoring sensors, valves and data loggers and software is on the market. Most systems are very affordable. The practice of overwatering inhibits optimal plant growth (roots need oxygen, for one thing) and can easily be avoided using sensor technology. Overwatering creates plant stress and underwatering creates plant stress. Soil moisture monitoring will find the "sweet spot", maximizing yield or plant quality and minimizing water usage. I wish more people would realize this.

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3. 3. Kermit-AUS 09:58 AM 9/25/12

   In Australia we have developed a system of soil survey (physical soil survey) analysing the soil within the root zone to map the variability within a property so the positioning of soil monitoring is done scientifically, this ensures the land is watered to the water holding capacity of the soil. The soil monitoring equipment then senses the uptake of the water by plants and advises when the water has moved through the root zone telling the user refill the root zone with water....

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