Page 126 - Agriculture_Form_Three

Agriculture for Secondary Schools

If the forage is harvested in the morning, wilting may only require the heat of the
afternoon of the same day. When forages are cut later in the day or on cloudy days,
it may need wilting till mid-day of the next day. The layer of material to be wilted
should not be thicker than 10 cm. If the layers are too thick, the forage will heat up
and begin to decompose thus encouraging wrong types of bacteria to grow. Where
necessary, the cut forage is turned over two to three times a day to encourage wilting.
If the fresh forage cannot be wilted, the fermentation of the silage will be improved
by mixing the chopped material with 3% to 5% molasses just prior to ensiling.
Although this is time consuming and a messy task, the rewards are well worth it.
Molasses can either be mixed thoroughly in forage or be spread as layers in the forage.
Where molasses is applied, the silage ferments better with its sweeter smelling and
the overall silage quality is good. Generally, two techniques are available to enhance
satisfactory fermentation of the harvested forage. These are wilting the forage prior
ensiling and or adding a fermentable substrate at ensiling.

(c) Chopping forage into small pieces
The harvester cuts the plants and then chops them into small pieces. However,
small-scale farmers can manually achieve similar chop lengths using machetes but
at a high labour input and more slowly. The chopped materials are then placed in a
pit in a ground or any other type of silo. The shorter the chop length, the better the
compaction hence less air is trapped in the forage resulting in better silage quality.
Chop lengths should be from 1 to 3 cm. Mechanised forage choppers will chop
quickly to very short lengths. Chopping is done to minimise loss of soluble sugars
as the material is allowed to wilt. Fodders are chopped into small pieces (≤ 4 cm) to
make them easy to compact in silo and create large surface area for fermentation to
proceed rapidly.

(d) Filling the silo, compacting, sealing and storage of the forage
A silo is any facility that can be made air-tight after the chopped material has been
filled and compacted. Ensiling is the process of filling the chopped material into
the silo. There are many types of silos. The commonest silo used by small-scale
farmers is the pit silo. However, the use of plastic drums and polythene bags as silos
is becoming more popular under small scale production due to their convenience in
handling and storage. Regardless of the type of silo, the forage must be compacted
as densely as possible, until it is difficult to insert your fingers into the stack. The
shorter the material is chopped, the more dense it can be packed and the less air that
will be trapped inside the stack. The chopped material is filled into the silo gradually
in layers of about one meter thickness. Molasses should also be added over each
layer to provide a source of soluble carbohydrates to the microorganisms. Molasses
enable rapid fermentation of the chopped material.

Student’s Book Form Twos Book Form Three
Student’
115

10/01/2025 12:31
AGRICULTURE FORM 3 9.11.2022.indd 115
AGRICULTURE FORM 3 9.11.2022.indd 115 10/01/2025 12:31