The sweet "gains"
by Mabelle R. Ilan
The Philippines is one of the
developing countries that are actively looking for alternative
source of fuel to reduce foreign oil import cost; to mitigate
pollution and global warming. One crop that is being considered
for propagation is sweet sorghum (Sorghum bicolor (L.) Moench.).
These sweet variety store large quantities of energy as sugar
in the stalk while producing reasonable grain yields.
How to Produce Sorghum
Sorghum is propagated by seeds. It matures in 100-115 days after
planting. Farmers can harvest the crop three times a year through
ratooning. Sorghum ratoon matures 85-95 days after cutting. If
the farmer opted to plant other crops sorghum can be used as
a component crop in multi-cropping system. It can be planted
after rainfed lowland rice, upland rice, corn or legumes. Sorghum
is drought tolerant crop. It only requires about 175 m3 of water.
Sorghum grows best in well-drained soil. It is best to plow the
field once and harrow it twice.
A hectare of sorghum would require 5-8 kilograms of seeds or
a plant density of 130,000-150,000 plants per hectare. Seeds
could be planted manually by hand or by using a planter. The
distance of planting varies during June-July planting the distance
of planting is 100 cm. apart 10 cm. deep while during September
October planting the distance of planting is 75 cm apart
and 15-20 cm. deep.
Just like any crop sorghum requires fertilizer for vigorous growth
and for higher yield. The general fertilizer recommendation for
clay loam soil is 80-30-30. It is important to practice thinning
before hilling up or side-dressing application of fertilizer.
It has been reported that the common pest of sorghum are shoot
fly and stem borer. Shoot fly attack the plant after germination
until 30 days after planting Stem borer can be prevented by using
granular insecticide applied on leaf whorls 2-3 granules per
Harvesting sorghum is similar to sugarcane. The panicles are
first cut and separated from the stalks. Stalks must be cut close
to the ground leaving about one node. Then the ratoon will sprout
in the node.
Sorghum as source of ethanol
Reports showed that sorghum like sugarcane and corn, also exhibits
C4 metabolism the reason why it is more efficient in converting
atmospheric carbon dioxide into sugar than most plants. The juice
squeezed out of sweet sorghum stalks contains about 15-20% sugar
that can be fermented into ethanol. It was also found out that
the ethanol produced is cheaper than sugarcane and corn. The
ethanol produced from sorghum can be used to blend petrol and
diesel. It minimizes carbon and monoxide emission in motor vehicles.
It is also known to be a clean burning fuel with
high octane rating. The procedures involved in the production
of ethanol include fermentation using yeast then, distillation.
Ethanol is used in the production of gasohol, a sulfur and lead
free fuel containing a certain percentage of ethanol in gasoline,
which has lower carbon monoxide and nitrogen oxides compared
to pure gasoline. A hectare of sorghum could produce about 3,000
liters of ethanol.
Other Benefits from Sorghum
For 150 years sorghum has been known as source of distinctive
type of syrup. The grain and stem of sorghum is also a source
of alcohol, sugar, fodder, fuel bedding, roofing, fencing, and
paper. But the important product now of sweet sorghum is ethanol.
Sorghum is also used in the preparation of silage. The silage
produced from sorghum has higher biological value compared with
the bagasse from sugarcane when used as feed for animals. It
was also learned that it is rich in micronutrients and minerals.
Evaluation and commercialization project
In the Bicol region, the Bicol Integrated Agricultural Research
Center conducted a varietal screening for sweet sorghum. The
study focused on the yield of sweet sorghum for ethanol and grain.
Five varieties were tested in Bicol conditions during the dry
season cropping of 2006-2007 namely: ICSR, ICSV93048, SPV 422,
ICSV 700, NTS 2. From among the varieties tested ICSV 700 is
the tallest with 334.95 cm.height. But considering the grain
yield SPV 422 obtained the highest yield with 9.55 metric tons
while for percentage sugar expressed in brix SPV 422 again obtained
the highest with 18.6 brix (measure for sugar content in liquids).
According to Romulo Cambaya, Agriculture
Center Chief II and at the same time researcher of BIARC, the
seeds produced during the first cropping were distributed to
Cararayan in Naga City, Goa, Canaman, Oas, and Pili. Knowing
the potentials of sorghum the center will undertake commercialization
of sorghum. In order to realize this project, a proposal was
submitted for ACEF funding.
Current Initiatives -
With the approval of bio-fuel act the government is bent on looking
for sources of bio-fuels that can be developed and sustained.
Ethanol from sorghum will not only save foreign exchange but
also reduce pollution and provide cleaner air. One of the constraints
seen in ethanol production is the supply of raw materials. Agencies
concerned must identify suitable varieties in every region that
can store large quantities of energy as sugar in the stalks and
at the same time produces reasonable amount of grains. Aside
from providing suitable varieties, technology must be provided
to the farmers in order to obtain the expected yield both for
the grains and for the ethanol. Linkages must be forged between
implementing agencies and the farmers so that resource complementation
With the many potentials of sweet sorghum, project implementers
and the farmers alike must be aware that in the initial stage
there will be more constraints than benefits. Their rewards will
be obtained later from the ethanol they produced.
Moreover, current technologies on ethanol production and sorghum
production need fine-tuning. The different varieties need further
testing before going into massive production. Once the production
technology is made available the ethanol plant has been set up
at the village level more farmers would be encouraged to venture
into sorghum production. In every production endeavor farmers
always look for a ready market for their produce. Hence it is
necessary that before commercializing the crop a thorough study
on the establishment of village level ethanol plant must be given