|
Saving the Harvest
Asian rice farmers experience postharvest grain losses that can
reach 30-50%. This means that, conservatively, farmers lose around
US$30 per ton of rice harvested. Studies by the International Rice
Research Institute (IRRI) in Cambodia, Indonesia and the
Philippines have found that postharvest losses occur mainly because
of spoilage and wastage at the farm, delay in drying, poor storage,
poorly maintained or outdated rice mills, and losses to pests
throughout the postharvest chain. These losses result in lower
quality rice for consumption or sale, smaller returns to farmers,
higher prices for consumers, and greater pressure on the
environment as farmers try to compensate by growing more rice.
Trainees in Laos manually harvest paddy.
Credit: Geert Claessens
With the urgent need to solve postharvest problems in developing
countries, the Postproduction Work Group (PPWG) was formed in 2003
by the Irrigated Rice Research Consortium (IRRC). By the end of its
first year, the PPWG had established partnerships in Cambodia,
Indonesia, Laos, Myanmar and Vietnam. The PPWG's key objectives
are to increase farmers' incomes through improved postharvest
management and technology, and to build a network of trained
postharvest researchers and extension workers in the public and
private sectors.
Farmers and extension officials test the
low-cost moisture meter on rice stored in a super bag in Hau Thanh
Village, Vietnam. Credit: Martin Gummert
One example of simple but effective postharvest technology is the
hermetic plastic "super bag" developed at IRRI. Working
with farmers in Battambang Province, Cambodia, researchers found
that, after 5-6 months' storage in a super bag, seed saved for
the next crop had germination rates of above 90%, or almost double
the 50% or lower germination rate of seed otherwise stored. One
farmer reported that he sold an additional 70 kilograms of seed in
the market, earning him an additional income of $9 (the reusable
super bag costs only $1).
The PPWG now focuses on evaluating hermetic storage systems with
farmers in Indonesia, Vietnam, Cambodia, Laos and Myanmar, as well
as with rice millers and traders in Vietnam, Myanmar and Indonesia.
Trials have shown that hermetic storage increases recovery after
milling of head rice, the valuable grain with at least 75% of the
whole, undamaged kernel.
One of the main culprits for deterioration in seed quality is
delayed or improper drying, especially when rice is spread to dry
under the sun. Mechanical dryers - another PPWG focus - are the
best way to ensure high-quality seed, especially in the wet
season.
At Nong Lam University in Ho Chi Minh City, Vietnam, the PPWG
trained dryer manufacturers from Laos, Myanmar and Cambodia are
manufacturing and testing dryer components. A manufacturer in Laos
who attended the training subsequently built low-cost dryers for
on-farm use that he plans to demonstrate and promote throughout the
country. In Cambodia and Vietnam, farmers' groups and
cooperatives are now installing their own flat-bed dryers.
Commercial furnaces, like this one in Long An
Province, Vietnam, with a 4-ton reversible airflow paddy dryer,
ensure high-quality produce. Credit: Martin
Gummert.
A participant from the Myanmar Rice and Paddy Traders
Association produced various dryer prototypes, including a low-cost
dryer with a 1-ton batch capacity for the farm and flat-bed dryers
with up to 4-ton batch capacity for commercial operations. The
association, which has installed eight flat-bed dryers at rice
mills and five others for farmer groups, now tours the provinces in
Myanmar to demonstrate the dryers to farmers and millers.
Although they offer major advantages, mechanical dryers add cost
to the drying process. To minimize drying costs, the PPWG helped
develop in Vietnam a new furnace fired with rice hulls.
|
