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New Subsurfer incorporates dry manure

Is it the next-generation manure applicator, or is it limited to only poultry litter?

That remains to be seen, but the Subsurfer prototype garnered a lot of interest at the North American Manure Expo in Norfolk in mid-July.

Designed by Dan Pote, a USDA Agriculture Research Service soil scientist, the applicator is one of the first to incorporate dry manure — poultry litter — into the soil. Heretofore, manure injection and incorporation have been limited to the liquid or slurry variety.

Pote, based in Boonville, Ark., spoke at the expo and demonstrated the implement, applying dry feedlot manure in it for the first time.

The Subsurfer is not commercially available, but prototypes built by BBI, a Cornelia, Ga., company, have been tested in Chesapeake Bay states in the Northeast. In tests in Southern states, it incorporated poultry litter on pastures, although some work has been done on no-till corn.

At a glance

USDA soil scientist develops a prototype tool to incorporate dry manure.

Most of the research has been done using poultry litter.

The applicator was demonstrated at the Manure Expo in Norfolk.

The applicator comes with a box that can hold up to 5 tons of poultry litter. Parallel augers in the bed draw the manure forward and pulverize it, then drop it through tubes between double-disk openers in front of the box. The incorporation components are corn planter units, with no-till coulters, double-disk openers and closing wheels.

Changing speed of the augers changes the application rate, according to Pote. “There is very little disturbance [in a pasture], with only a small slot created. It’s deep enough to prevent the poultry litter from running off the field. It’s also deep enough to prevent most nutrient losses.”

In the research, Pote found that the subsurface application of litter lowers nutrient runoff and ammonia emissions by at least 90%. It also was shown to increase forage yields slightly.

“The only way to apply dry product in the past is to surface apply it, leaving the potential for runoff or nutrient loss,” he said.

Tom Way, an ARS scientist in Auburn, Ala., has developed a different prototype of a poultry litter soil incorporator for row-crop use. He can adjust row spacing with his implement.

Chris Henry, University of Nebraska-Lincoln Extension engineer and co-chairman of the expo, said the Subsurfer performed well in a short demo. The manure was scrapped off the pad in a nearby feedlot and was drier than feedlot manure would normally be, he said.

Henry said the commercial application of feedlot manure on a large scale below the soil surface is several years down the road. He believes feedlot manure would need to preconditioned in some way, either by composting or by use of a device that removes large chunks of the product.


SOIL INCORPORATION: This Subsurfer prototype was demonstrated at the North American Manure Expo in Norfolk. In a short demonstration, it incorporated dry feedlot manure into the soil.


AUGERS ON BOARD: These parallel augers in the bed of the Subsurfer bring the material forward and help in pulverizing it.

This article published in the September, 2011 edition of NEBRASKA FARMER.

All rights reserved. Copyright Farm Progress Cos. 2011.