Dohrmann: Applicator Technology and Maintenance

Posted on February 22, 2013 in Forage Foundations


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Applicators are a critical tool for anyone looking to apply inoculants at harvest. At the Vita Plus Custom Harvester Meeting, Dan Dohrmann of Dohrmann Enterprises, Inc. shared advancements in applicator technology and general equipment maintenance.

There are three basic types of applicators, he said, granular, conventional and low volume/concentrate.

A granular applicator is used to apply a granular inoculant. The product is moved through the applicator with the use of a paddle wheel or auger, both of which can require a lot of power to operate.

For some time, the conventional applicator was the only one available for liquid application. It resembles a smaller version of the field sprayer and requires high volume pumps, filters and nozzles. At first, users were applying the water-soluble inoculant at one gallon per ton of silage. Since then it has been reduced to one quart, followed by one pint. Today, Dohrmann said, the maximum recommended concentration is 8 fluid ounces per ton, with a minimum application rate of 16 ounces per ton per nozzle to minimize the risk of the nozzles plugging.

Low volume/concentrate applicators make up a smaller footprint and place less weight on the harvester. It should only be used to apply concentrated water-soluble inoculants. Each low volume/concentrate applicator on the market has components that are unique to the system’s design.

The low volume/concentrate name comes from the fact only 0.33 to 1.28 fluid ounces of overall solution is applied per ton. That results in less water required and less time spent refilling the applicator.

Due to its compact size, some units use an insulated cooler as the tank. Keeping the product cool is beneficial to that inoculant, he said.

The downfall to these is that the units have orifices/nozzles that require stringent maintenance to avoid plugging.

According to Dohrmann, there haven’t been a ton of updates or new things from an applicator standpoint.

About 8 years ago, John Deere created a harvester yield monitoring system, which will allow applicators to tie into the yield monitor and inoculant will be automatically applied through the system.

Other manufacturers have also been working on yield monitors, he said. The one from John Deere was developed as an open concept, which allows applicators from other companies to plug into it. Dohrmann is unsure if that will be the same for other manufacturers.

“You know the importance of an inoculant,” Dohrmann said. “If your equipment doesn’t work, you’re not going to be able to apply it.”

When it comes to maintenance water is your friend, he said, recommending the use of a lot of water and to flush the applicator often.

“More often than not, when there are issues with equipment, a lot of it comes down to maintenance,” he said.

Throughout harvest, he recommended rinsing the pumps, filter(s), hoses, nozzles and tank between cuttings with a lot of water. Any residual left behind could promote the growth of additional bacteria.

In addition, inoculants are an acid-producing product, he said. If the system is not flushed and an acid builds up, once a little water is added, the pH will actually drop. Therefore, if flushing with straight water, flush it often and flush a lot. Or neutralize the acid with a baking soda/water mix and then rinse with water.

Filters should also be cleaned and reinstalled.

To winterize an applicator, drain the water from the system and pump RV antifreeze into it. This will keep the seals and gaskets from freezing.

At spring start-up, Dohrmann said to verify that the pump motor runs. Then, inspect all gaskets – filter, swivel connections, nozzles – to make sure they are not twisted, cracked or broken in any way that would let in air. A non-petroleum based o-ring lube can also be applied to the gaskets. Clean the filters and reinstall.

His pre-start-up checklist includes:

  • Check to see if the motor runs
  • Verify gaskets are in place, with no cracks or kinks
  • Test that the hose clamps and fittings are tight
  • See if the valve kit needs replacement on a conventional applicator
  • Check if the pumping tube needs replacement on a low volume/concentrate liquid applicator. This needs to be replaced every year, he said. When it fails, the entire system won’t work.

The long and short is to “keep it clean, rinse it out, take care of it and replace it when needed,” Dohrmann said.

Article written by Progressive Forage Grower Editor Karen Lee

Category: Equipment
Forage Foundations
Forage inoculants