Spraying should account for very little energy used on the farm. At about two tenths of a gallon per acre, spraying is not an energy-intensive field operation. However, poorly managed spraying can lead to re-sprays making spraying not only energyintensive, but economically very inefficient as well.

There are several potential pitfalls to efficient application of crop protection materials, but the good news is that they can all be managed. Nearly as costly as a re-spray are the inefficiencies resulting from overlap, poor calibration and offtarget placement. Round these out with poor spray distribution or nozzle selection and there is potentially a lot of room for improvement. With little or no calibration, it is estimated that as few as 5 percent of spray events are within the plus or minus 5 percent of target rates considered reasonable accuracy.

The surprising statistics from some research show that crop protection materials are often over-applied by more than 20 percent due to overlapping and poorly calibrated sprayers. An herbicide program with a projected material cost of $20 per acre may cost as much as an extra $4 per acre for the waste created by overlap. Similarly, a $50 program might cost an additional $10 per acre. Improving accuracy can save a potential $10,000 over a thousand acres.

A simple sprayer calibration can make huge differences, and it might even be worth investing in a light-bar for guiding sprayers through the field. The least expensive improvement is proper calibration, and the cost of calibration is almost free, and the returns are enormous. Calibration may very well be the best investment you ever make.

The perfect time to calibrate is while the sprayer is still clean at the beginning of the season. Start with a new set of nozzles if you covered a lot of acres last season and follow the calibration procedures found in MU publication G1270 (http://muextension.missouri.edu/xplor/agguides/agengin/g01270.htm).

The chances are very high that without further calibration throughout the season that misapplication beyond the 5 percent margin is very likely. As nozzles wear, their output trends higher. Consider a re-calibration whenever you do a thorough sprayer cleanup. It doesn’t need to require more than about twenty minutes. If that single re-calibration saves 5 percent on say the last 500 acres sprayed at $25 per acre then that twenty minutes worth of work would come in at about $1,875 per hour. Realistically, the actual savings for that twenty minute exercise are $625 and remember that any money saved is, as always, completely tax free.

Please follow safe practices for limiting exposure whenever mixing, loading or applying crop protection materials. See MU publication G1917 for details (http://muextension.missouri.edu/explore/agguides/agengin/g01917.htm).

Bill Casady
(573) 882-4370