Not too much. Not too little. Just right.
"When you're working with pesticides and herbicides, you want to be certain you put the right amount of chemical in the right place at the right time," said Jeremy Greene, an entomologist with the Clemson University Extension Service who has developed a new mobile application to help farmers do the math.
"Too little spray and you're not solving the problem. Too much and you're wasting money and potentially damaging the plants," Greene said. "To be sure it's the right amount, farmers must calibrate their sprayers."
Sprayer calibration — determining how much liquid can be sprayed across a field in a certain time and adjusting the sprayer to deliver it exactly — is a fairly straightforward job.
However, sprayer calibration involves a complicated set of variables: Farmers must account for the speed of the sprayer as it travels through the field, the rate at which liquid flows through the sprayer nozzles, the pattern of those nozzles and the width of the sprayer boom, as well as the recommended concentration of the chemical being sprayed.
"When I started out as a county agent 20 years ago in Georgia, they devoted a whole day of training to sprayer calibration. That's how complicated it can be," said Scott Sell, a Clemson Extension agent in Allendale. "I've taught classes on it and it's still tough."
"It requires a lot of math," Greene said. "In the past we created really specific spreadsheets that enabled farmers to make all those calculations quickly, but they weren't easily portable where the work needed to be done.
"Developing the app for mobile devices and tablets puts all that right calculating power where the farmer needs it," he said. "It can be done right in the field as the farmer is testing the sprayer, which speeds up the process and makes it easier to be sure the adjustments are precise."
The "Calibrate My Sprayer" app is available free on the Google Play Store both in Apple (iOS) and Android versions.
Greene envisions a suite of similar applications for other calculation-intensive farm decisions in the near future.
"Farmers are accustomed to advancements in science and technology when it comes to their crops and the tools they use to produce them," Greene said. "Mobile apps are just allowing information technology to catch up out in the field."