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Harvest
Management Improves Silage Quality
Compliments of
Agronomy Services Department
Producing high-quality corn silage only begins with planting TMF
Silage-Specific� Corn Hybrids. An important part of the process is
proper harvest management. Follow the suggestions below and you will be
rewarded with corn silage that helps put more profit on your operations�
bottom line!
Harvest Time Determination
A key to producing high-quality silage is determining when to begin
harvest. To properly time silage harvest it is necessary to evaluate grain
maturity, whole plant fiber level, and whole plant moisture. In the past a
general rule of thumb has been to begin harvest at 1/3 to � of kernel
milk-line and to finish at 2/3 milk-line. However, because of the varietal
characteristics of hybrids, this should only be used as an indicator. More
satisfactory results will be obtained by determining the proper moisture
level of the plant and harvesting at the appropriate moisture percentage.
The following table provides the recommended whole-plant moisture content
for corn silage for the various types of storage units:
Silo Type Recommended Moisture %
Upright 62-65
Horizontal 65-68
Bag 62-68
Adapted from: Corn Silage Production, Management and
Feeding-NCR574 North Central Regional Publication
How can you accurately determine harvest time moisture?
Accurate determination of plant moisture levels will be very important
to future quality of the harvested silage. Varietal characteristics such
as plant stay-green, kernel dry down, and the effects of environmental
conditions affect the whole plant moisture at any given time. However,
there are several methods available to determine whole plant moisture
levels. Two of the most common methods are the Koster tester and the
microwave oven. The Koster tester is a portable, forced air electric
drying unit. Silage samples take about a � hour to dry to receive an
accurate moisture level reading. The microwave oven method is also widely
accepted. Follow the steps below to determine plant moisture using the
microwave method.
Using the Microwave Oven Method for determining moisture content of
silage:
1) Begin by selecting 5 to 10 corn plants that represent the field as a
whole. Chop these plants into a representative silage sample. 2) Weigh a
100-gram sample of chopped silage on a paper plate, excluding the weight
of the plate. We recommend duplicate samples for a more accurate
measurement. Follow the procedure one sample at a time.
3) Spread the silage evenly over the plate and place it in the
microwave. Place an 8-oz glass � full of water in the microwave�s back
corner to prevent igniting the sample.
4) Heat the sample for three minutes initially on high power.
5) Remove the sample from microwave, weigh and record the weight. Stir
the sample and return to the microwave.
6) Repeat step 5 again, but use one-minute time intervals. To prevent
burning, use 30-second time intervals as it approaches dryness. Continue
drying and weighing until the weight changes by less than 1 gram.
7) The final dry weight, minus the plate, is the dry matter percentage.
To determine moisture content, take the final dry weight, minus the paper
plate, and subtract from 100.
8) Repeat steps 2 through 7 with the duplicate silage sample and
average the results.
9) You now have determined the moisture content of the silage.
Other Important Management Steps in Harvesting Corn Silage
In addition to determination of whole plant moisture, chop length is
another important aspect of proper silage harvest. Silage harvesting
equipment should be set to attain the desired chop length, or what is call
theoretical length of cut (TLC). A TLC of 3/8 inch is recommended for
unprocessed whole plant corn silage; a TLC of � inch is recommended for
processed silage. Particle size at harvest will be affected by knife
sharpness, harvest speed, shear bar setting, and crop moisture. Drier
materials will need to be cut shorter to ease packing.
The next and final step in producing quality silage is the proper
packing and covering of the harvested material. Proper packing
provides the environment necessary (anaerobic, or oxygen-free) for
effective fermentation to occur soon after harvesting is complete. Silage
that is more densely packed will have reduced dry matter loss and higher
feeding quality than silage less densely packed. It is also important
to adequately cover stored silage to reduce or prevent spoilage.
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