MISSISSIPPI STATE -- Spraying chemicals is a significant part of the cost and control of modern farming, and calibrating the implements can make a difference in efficiency.

Herb Willcutt, agricultural engineer with the Mississippi State University Extension Service, said calibration is a simple procedure that can potentially save thousands of dollars and protect the environment.

"Farmers should calibrate sprayers every time the equipment goes to the field with a change of material being applied, and at least once a week if the same chemical is being used," Willcutt said.

It costs about $4 to $5 an acre in equipment operation costs each time farm equipment is driven across a field. Willcutt said it is important to use these costly trips wisely.

"If you spray too much chemical, you run the risk of crop damage, but if you use too little, you risk not controlling whatever you were spraying for," Willcutt said.

Producers can use a few methods to calibrate their equipment. Actual calibration involves measuring to see that the correct amount of a chemical is sprayed over a set amount of land. Producers can make less precise checks when they know how many acres are in a field and how many gallons of chemical should remain in the equipment after spraying.

Willcutt said MSU's Department of Agricultural and Biological Engineering offers a shirt-pocket card explaining the 128th-an-acre method. This card is available from local county Extension offices. Sometimes vendors provide this information with the equipment, and Mississippi Farm Bureau has a stick-on decal for the sprayer tank.

"The first time you calibrate a piece of equipment, it may take 10 or 15 minutes, but usually it can be done in less than five minutes after that," Willcutt said.

Ann Ruscoe, Extension director in Coahoma County, said she reminds producers every chance she gets to calibrate their equipment regularly.

"I emphasize correct calibration and proper maintenance of calibration equipment at production meetings and all private applicator training sessions because there is a potential for error in each application," Ruscoe said. "This is something that needs to be done periodically throughout the entire season."

There are more than 300,000 acres of row crops in Coahoma County. Last year Ruscoe worked with a producer who had 13,000 acres of cotton. The calibration on his spray equipment was off and he was applying 20 percent more chemical than was necessary.

"That excess 20 percent could have cost him more than $250,000," Ruscoe said.

But the dollar savings is not the only reason farmers should maintain spray equipment at proper calibration.

"Our farmers are very environmentally conscious in their application of pesticides," Ruscoe said. "Not only do they try to apply the proper amount because these chemicals are very costly, but they also do their part to maintain a balance in the environment that is safe."