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Novel rig sidedresses manure

Hog manure is hard to
handle, but it’s a very good source of crop nutrients. That keeps growers like
Adam Wirtz searching for new and better ways to apply it.

Wirtz is the farm manager
for a family-owned operation near West Bend, Iowa, that grows crops and raises
hogs in confinement buildings. They plan to switch one of those buildings to
organic hog production in the near future. Because they like to grow their own
corn for their hogs, they have already started raising 200 acres of organic
corn each year.

They can’t use commercial
nitrogen to raise organic corn. Consequently, hog manure is a key part of their
production system. The organic corn is raised in rotation with oats and
clover.  After the oats are
harvested, the clover grows up through the stubble. The clover is not
harvested. In the fall, Wirtz applies hog manure to the clover and then rips
the ground. Organic corn is planted the next spring.


Wirtz only applies a
two-thirds rate of hog manure in the fall, however. “We feel like we lose
some,” he explains. “We get a way bigger kick with that last one third if we
wait and put it on in the summer.”

Three years ago, Wirtz
modified a 16-row Hiniker cultivator to sidedress liquid hog manure in every
other row middle. It was a fairly straightforward conversion. He cut the ends
off the cultivator sweeps to make them less aggressive. They are now about 7
inches wide. 

“We didn’t want to move a lot of dirt,” Wirtz explains.

He also modified the folding
mechanism so the cultivator wouldn’t hit the top of the tank when folded for
transport. And because other nearby organic growers also use the sidedress rig,
he built it so the outside sweep on each side can be removed to sidedress 12
rows instead of 16. It’s used on 1,500 acres each year.

Because of concerns about
compaction, the family bought a relatively small 4,800-gallon tank and had the
dealer install LandLuvr tracks. Those tracks are 12 feet long and 18 inches
wide, so they really spread out the load. Wirtz uses tracked tractors, also.

The first year he had the
sidedressing machine, Wirtz and his crew did it themselves. “But we just didn’t
have the equipment it took to keep it running in the field,” he says. “We just
had one small tank that could nurse it. And in addition to that, we were trying
to spray and sidedress anhydrous ammonia on our conventional ground.”

In 2009, he turned the task
of sidedressing over to Mike, Calvin, and John Bruellman, who run a custom
manure application business at Ottosen, Iowa. The crews often run around the
clock both in the fall and before spring planting, but they have a summer lull.
“Since they had the equipment and the people, we let them take it over,” says

Bruellman has several
7,300-gallon tanks that he uses to nurse Wirtz’s applicator. For sidedressing,
he widened the wheel spacing on a big John Deere wheel tractor to 120 inches to
match Wirtz’s sidedressing rig and other field operations.

“Weeds will grow wherever
you have compaction,” says Wirtz. “So weeds grow in our wheel tracks. We didn’t
want an extra set of wheel tracks out there.”

Wirtz typically applies
about 2,000 gallons of liquid hog manure per acre at sidedressing. He figures
that supplies about 60 to 80 units of nitrogen.


“We tried 1,000 gallons, but
with the 40-foot span, the application wasn’t as even as we would like,” says
Wirtz. “There wasn’t enough volume for what we were trying to cover. When we
bumped the rate up to 2,000 gallons, we were able to keep the tubes full and
get a little more uniform coverage.”

The sweeps run 2 to 3 inches
deep. “We’re just trying to cover the manure,” says Wirtz. “Because it is
fairly dry then and because we are putting on such a small amount, it pretty
well soaks right in.”

Even with good equipment,
it’s still a big job.

It typically takes two nurse
tanks to supply the applicator if they are working within 2.5 miles of a hog
building site. Beyond that, it takes three nurse tanks. The Wirtz operation has
enough hog sites that they rarely haul more than 3 miles.

Bruellman usually limits
sidedressing to daylight hours, although the equipment was outfitted with an
RTK guidance system after the 2010 season. That may make it more feasible to
sidedress after dark. 

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