Guidance systems aid spray accuracy in reduced-tillage cropping systems

South-central Kansas farmer Lee Scheufler likes new technology for improving weed control in no-till crop production.

“With no-till, chemical weed control is essential,” Scheufler said during the No-till Oklahoma Conference in Oklahoma City. “Spraying and sprayers are crucial for success."

He, like other farmers on the program, said producers can easily justify owning a sprayer because of the advantage it gives them on timely applications. “A grower can hire spraying done and be successful, but owning a sprayer allows for timing flexibility.”

He said goals for spraying no-till crops should include using the right product, the right amount, at the right place, at the right time and at the right price.

He outlined advantages of several spray options, including auto guidance with the John Deere RTK system. “That offers accuracy to 1 inch and is repeatable,” he said.

He said other options include automatic boom section control, automatic boom height control and pulse width modulator tips.

“AutoTrac follows a straight line,” Scheufler said. “A GPS receiver and RTK radio offers up to 12-mile range from the base system. We bought our own base system and get about a 6-mile range, but that should extend with new software.”

He said boom section control, with a touch screen monitor, can be map based or used with a prescription rate. “The RTK offers precise positioning.”

He said growers should be aware of potential coverage problems with a long boom. “When cutting sharp corners one boom goes backward as the other speeds up. Take that into consideration as you make the turn.”

He said two companies should be releasing new sprayers that change speeds for the inward and outward booms to help correct cornering problems.

He said pattern control may be compromised with varying boom height. “Spraying too close to the target results in skips and spraying too high above the target may result in drift and skips. It’s important to maintain height uniformity across the field.”

He said sensors mounted at various points along the boom of newer sprayers (He’s using a John Deere 4730 with a 90-foot boom.) help maintain height across uneven terrain, including terraces.

“We may lose some efficiency with changes to avoid terraces, but that’s better than crashing the boom.”

Scheufler said a NORAC spray height control system that puts the sensor out front of the sprayer seems to be more responsive than one that fits closer to the boom, but does not integrate with some switches on the display monitor.

John Deere offers a Boom Trac Pro spray height control unit.

He said pulse modulation of the spray tip helps control droplet size. “With smaller droplet size, potential for drift increases.” He said a Capstan system uses a solenoid at the nozzle to alter the amount of product released by varying the amount of time the nozzles open in one-tenth of a second. If it opens for half the time, it releases 50 percent as much material during the pulse as it would if it were open 100 percent of the time.

“We can monitor droplet size over a range of speeds.”

Scheufler said spraying is a critical aspect of no-till agriculture. “We have to select the right products and a good sprayer can help with timing, application accuracy and reduce drift. An operator can be confident with an accurate guidance system.”

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TAGS: Management
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