Material Handling of High Moisture Corn
Comments by James I. Sprague, Ph.D. Nutritionist
Speed of Harvest, Storage a Key
Darrel Schwartz of DKS Dozing and Roller Mills Incorporated at Dighton,
Kansas, recognized the need for speed in the processing of high moisture
corn during the grain harvest. He developed and fabricated roller
mills and back up equipment that will rapidly process grain. The equipment
includes large buckets for the front end loaders and large conveyors
to move the high moisture grain. Note the picture the unit that is
10 roller mills (5 on each side). It takes several combines and trucks
to keep up with this unit since it will process 25,000 to 28,000 bushels
per hour.
Schwartz and other manufactures build mills from
one unit up to 6 units. The DKS mill with 10 units may be the world's
largest. Most of the large units will be owned by customer operators.
Two or three units may work at the same time at a feedlot at the peak
of harvest.
Originally large modified tub grinders processed most of the high
moisture corn, but now roller mills are also used primarily because
of the speed of the processing.
Roller Mill vs. Hammer Mills for High Moisture Corn
Both roller mills and tub grinder hammer mills are successfully used.
Tub grinders are preferred by some feedlots and their nutritionist
to achieve smaller particles for superior grain conversion of the
starch. The tub grinder or other hammer milling systems produces many
fines and complicates the daily ration management. However, this disadvantage
can be overcome by using larger hammers to get a crushing action and
modifying the screen configuration.
Most roller mills used for high moisture corn have a differential
on one of the rollers which provides a grinding action. Most units
are equipped with four corrugations per inch. With the "grinding
action" of the differential roll and the handling and packing
of the high moisture corn we have observed up to 20 percent fine particles
and 80 percent larger pieces of kernels that are split in two and
four pieces. Finer corrugation are suggested for smaller particle
sizes but this slows up the processing time and power requirement.
Feedlot managers and their nutritionists prefer moisture levels of
30 to 35 percent moisture when the grain arrives at the silo. The
harvest season and processing needs to be coordinated in all steps.
This includes weighing the trucks, sampling the grain, unloading the
trucks, processing the grain, packing the grain and finally the covering
of the silo.
Promptness of Packing and Covering is Critical
Speed of harvest and processing are only part of the key points. The
packing and covering process is very important to achieve a superior
grain product. Excluding the air to prevent heating and molding can
only be achieved by prompt spreading of the grain over the surface
of the silo and then the action of the tires and tracks of the dozing
equipment, plus the weight of the mass will exclude the air if the
silo is promptly covered with plastic sheets or other materials.
The usual material for covering is only plastic sheets placed immediately
on the grain at the completion of filling the silo. The plastics sheets
are often secured with used tires. We have seen dirt used successfully
to hold the plastic in place. Also wet clumps of alfalfa or grass
silage works well to hold down the plastic. A molasses product to
cover and seal silos has also been used successfully.
Silos of Every Size and Shape for High Moisture Grain
Large pit or bunker silos are used by most feedlots. An important
point is good drainage away from the silo or a method of removing
the rain water or snow melt.
Storage in an "Ag-Bag"
The Ag-Bag International Company from Astoria Oregon, reports that
the use of their storage method is growing in popularity. Certainly
the preservation and exclusion of air is a plus for this storage method.
One of the problems for large farmers and feedlots is the speed of
the storage system has to match the speed of harvesting and grinding
of the grain. ©
