Monitoring carbon dioxidealong with the
standard humidity and temperaturemay help detect insect and mold problems
more effectively. Photo courtesy of Microsoft Clipart. |
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Grain Moisture Measurements May Divert Mold,
Insect Infestation
By
Sharon Durham August 28, 2008
Grain storage bins are routinely monitored for temperature to
control insect and mold problems. Now an Agricultural Research Service (ARS)
scientist and his colleagues at Kansas State
University (KSU) have preliminary research findings showing that monitoring
carbon dioxide--along with humidity and temperature--also may help detect
problems more effectively.
Grain moisture content and temperature are the primary factors
affecting grain deterioration in storage. If these factors are not properly
monitored and controlled, grain quality can deteriorate quickly due to mold
growth and insect infestation.
ARS engineer
Paul
Armstrong at the agency's
Grain
and Marketing and Production Research Center in Manhattan, Kan., and Haidee
Gonzales and Ronaldo Maghirang at KSU monitored a simulated grain storage bin
during aeration to determine if high-moisture grain, or adverse storage
conditions, in the bin top could be detected using sensors to measure relative
humidity, temperature and carbon dioxide levels.
Relative humidity and temperature can be used to estimate grain
moisture, while carbon dioxide levels indicate the amount of respiration due,
primarily, to molds. Current technology allows relative humidity and
temperature sensors to be placed at multiple points within the grain mass.
Carbon dioxide sensing is more feasible at an aeration duct.
In the study, sensors were placed at different depths in the bin.
High-moisture grain-- comprising about 11 percent of the volume--was placed at
the top of the bin and produced high amounts of carbon dioxide, which in most
cases was easily detectable during aeration.
Lowering grain temperature with aeration diminished the amount of
carbon dioxide produced, making it more difficult to detect unless the carbon
dioxide sensor was located very close to the wet grain.
Relative humidity and temperature sensing gave good estimates of grain
moisture for all conditions, but under some grain conditions, high carbon
dioxide levels persisted for grain considered to be at safe moisture and
temperature conditions. Combining relative humidity, temperature and carbon
dioxide measurements gave reasonably accurate measurements of grain moisture
content as well as overall storage conditions.
ARS is the U.S. Department of
Agriculture's scientific research agency.