Moisture meter targets grain loss in developing world

American researchers have developed a new test to measure moisture in stored grain.

While a wide variety of other moisture testers are already on the market, this one is specially designed for its low cost and ease of manufacturing.

Paul Armstrong, lead scientist with the U.S. Department of Agriculture’s Agriculture Research Service, said the Post Harvest Loss meter is as accurate as low-cost meters now on the market but not as good as the high quality ones available.

He said the ability to easily mass produce a large number of the PHL meters make them a good fit for use in developing countries.

“As designed, it works well for measuring bulk samples,” he said in an email.

“It should be very cheap to produce in mass quantities. The sensor is very stable and replacing it can be made very easy.”

Research has focused on use in the developing world, but it could also work for testing grain in bags in the industrialized world.

The hand-held unit, costs about $100 to make, can be made with readily available parts and requires no special equipment.

Users insert a probe attached to the device directly into a bag of grain. After about six minutes, readings appear in a display window.

The meter measures the relative humidity and temperature of the air in the grain — two main factors used to estimate moisture content, said Armstrong, who developed the meter with his colleagues at Kansas State University.

They have concentrated their research for its use in corn in Ghana. Grain there is usually stored in bags to keep out mould and insects. During the wet season, Ghana can see 30 percent losses in grain moving from field to table, mainly because of mould, but insects also play a role.

The country can experience as much as 20 percent crop loss during the dry season, although Armstrong cautioned that those numbers are drawn from his memory and may not be exact.

Farmers in Ethiopia, Guatemala and Bangladesh are also evaluating he the PHL meter.

Armstrong said the unit could also be used in the silos and grain bags used in North America. In fact, he previously worked with OPI Systems to develop a cabled system that works on the same sensor concept.

He said the PHL meter has been used mostly in corn, soybeans and chickpeas, but it can be used for all major grains and legumes.

Armstrong and his co-workers are continuing to work on the meter to extend its battery life, add smartphone connectivity and reduce costs.

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