by Dexter B. Dombro
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| Worker harvesting elephant grass. |
Amazonia Reforestation and La Pedregoza are making as many natural fertilizers as possible for our tree
cultivations. To do so requires quality manure, this is why we maintain a
stable with Zebu cattle. Obviously, the nutritional content of the feed our
cows eat has a bearing on the quality of that manure, so we are looking at ways
of enhancing their diet during the dry season (January through to April), when
native grasses dry up and are little better than cellulose. One solution for
improving animal feed is to make silage, so this article explains the process
we are employing at our plantation.
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| Feeding elephant grass into chopper. |
First off, our definition of the word silage is
as follows: fresh grass or other green fodder chopped, mixed with molasses, compacted
and then stored and fermented in airtight conditions, to be used as animal feed
when climatic conditions are appropriate. What makes silage important?
Basically, it retains up to 80% of the nutritional value of the fresh grass or
fodder, whereas hay or dried fodder will lose up to 80% of its nutritional
value, so silage is much better for one’s cattle. Needless to say, as a result
the quality of the manure from silage is better than from dried fodder when
preparing compost or other fertilizers.
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| Worker dwarfed by elephant grass. |
We plant a variety of grasses at La Pedregoza.
The most productive one is African elephant grass (Pennisetum
purpureum), which can grow to be 4 meters tall, spreads well in the
pasture and produces up to 40 metric tons per hectare per year of biomass.
While it propagates by seed, it is more efficient to plant elephant grass using
stem cuttings when the plant has matured. The grass is tolerant of poor soils
and low rainfall, which is another plus in some tropical locations. This high
rate of biomass production means that elephant grass is not just a useful
animal feed, but could also be ploughed into poor soils to enhance the soil’s
organic material, carbon and nitrogen content.
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| Brachiaria pasture at La Pedregoza. |
There are two other grasses we cultivate in our
silvopastoril project, both of which have reasonable protein contents and can
be used for silage. Brachiaria decumbens is
bitter tasting, while Brachiaria humidicola
is sweeter and better nutritionally when cultivated with other legume plants.
Obviously having a variety of grasses and fodders enhances the cows’ menu and
the quality of the manure. Nevertheless, in this article we are going to
concentrate on making silage with elephant grass.
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| Filling trailer with chopped grass. |
We harvest using machetes, much the way sugar cane
is harvested. The bundles of elephant grass are then carried to and fed into the
chopper, which in turn is powered off the tractor’s PTO, and which casts the
chopped grass into a wagon. We find that one wagon filled is about 1,200 KGs of
chopped material, which is a reasonable amount for one day’s silage making.
1,200 KGs represents 2 hours of harvesting and chopping with 2 to 3 farm
hands. Any more harvested and chopped,
and one may end up with material that is already dry and less nutritious a day
later.
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| We use a silage press to remove air. |
We use a 2-barrel manual silage press, which allows
for a fast work flow. Each barrel accommodates a heavy gauge plastic bag that
can take 40 KG of chopped grass. This means that our daily target is the
production of 30 bags of silage weighing some 40 KG each. Mixing the chopped
grass with molasses and then stuffing and sealing the bags, as well as depositing
them in the storage shed takes a further 4 hours with the labour of 3 farm
hands. We like 40 KG bags of silage, because they are easy to carry and
transport, as well as easy to stack and store.
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| Mixing grass, molasses and cattle sale. |
The mixing of the silage is very
important, as an even mix ensures good fermentation. We add 10 KG of molasses
to every 200 KG of chopped grass, as well as about 1 KG of cattle salt. The
mixing is done with shovels and rubber boots, until the molasses is well
distributed throughout the grass. Next, we fill the bags, putting first 10 KG
of mix into the bag and then compressing it, before adding more material and
compressing it. The compressing is done in order to remove as much oxygen as
possible.
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| The press removes all air before sealing the bag. |
Making silage and its fermentation is an anaerobic
process. If air is left in the bag or mix, the silage will go bad and it will
smell horrible, at which point it is only useful as compost. The secret of good
silage is therefore to remove as much air as possible before sealing the silage
bags. Within days the storage area will have a nice aroma, similar to beer or
wine making.
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| Silage bags are stored away from direct sun. |
Once the bags are filled and
compressed, they are sealed tight with a cord and taken to the storage area. In
tropical areas, it is best to store the silage in a shaded area, away from
direct sunlight. The silage is ready within 15 days of being bagged, and can
last for up to one year, though we generally use it within 4 to 6 months of it
being bagged. By looking after the bags and keeping them out of the sunlight,
we are often able to reuse the bags, which can reduce costs. Silage produced in
the farm is very cost efficient, as one can save by not buying third party
products, and of course there is no transportation cost to the farm gate either
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| Happy cows pooping for better compost! |
The process above can also be used to make Bokashi,
which is a Japanese fermented type of compost that is much richer in nutrients
and quite a bit quicker to produce. The difference is that one would also have
to prepare Bokashi bran and mix that bran in with the chopped material, manure,
kitchen scraps and molasses. Other than
that the process is pretty much identical. Recipes for making Bokashi bran can
be found on the internet, using wheat bran, rice water, sawdust or other
ingredients.
© 2017 Plantacion Amazonia el Vita S.A.S.
