Technology: silo production and use

The main POSTCOSECHA technology element are locally produced metal silos, where grain is stored and protected. POSTCOSECHA metal silos are manufactured by local tinsmiths out of galvanized flat iron sheets.

Local tinsmiths are normally able to build the silos with readily available tools after having received proper construction plans and construction training. Construction plans are available for 5 silo sizes (holding between 180 kg and 1360 kg of grains). Training manuals for tinsmiths are available. Production cost of silos is roughly between 30 and 100 US dollars (depending on size, cost of galvanized iron sheets, and cost of labor). While the manufacturing process is low tech, quality standards have to be adhered rigorously to allow for construction of a hermetic silo.
see documents on silo production >>

If properly used, POSTCOSECHA silos will last up to 20 years. Farmers need to be trained before using the silos, mainly on proper drying of grain before storage, proper hygiene and proper application of fumigants. Proper silo use by farmers is supported through specially designed, long lasting posters glued onto every silo.
The protection element with the greatest impact on loss reduction is fumigation against insect infestation by the use of phosphine tablets. Fumigation is only effective when the silos are hermetically sealed. Recently, alternative protection methods have been introduced, namely the elimination of oxygen by burning a candle in the hermetically sealed container. Little practical information is available about such alternatives.
see documents on storage technology >>

Apart from metal silos, the POSTCOSECHA program also promoted alternative storage technologies for poorer households:


Drying cribs help avoid losses that occur with the common practice to leave maize cobs in the field until the rainy days pass. Instead the maize is dried in the cribs and then in the sun before being ready for storage.
see "Guía de cosecha temprana de maíz y secado en casetas mejoradas" >>
see other documents on storage technology >>

Main critical technology factors

Silo quality:
competence of local tinsmiths, quality of locally used tinsmith tools, silo quality control after production, silo maintenance

Availability of raw materials in local markets:
mainly galvanized iron sheets of adequate size / thickness / galvanization and Phosphine tablets

Storage diligence:
dryness of grain, hermetic sealing of silo, effectiveness of fumigation