John K. Saichuk, Schultz, Bruce | 4/19/2005 10:29:18 PM
CROWLEY – Cooling rice and other crops quickly after harvest is the first step to getting the grain to a proper moisture level, an expert said at a recent seminar on grain drying sponsored by the LSU AgCenter.
Farmers should try for gradual drying, and that often means not using any heat at first, said Dr. Dennis Gardisser, research professor of biological and agricultural engineering at the University of Arkansas.
Gardisser’s comments came during a seminar held last week (Nov. 30) at the LSU AgCenter’s Rice Research Station.
"Let Mother Nature help you the first two to three days," Gardisser said. "More air is the key to speeding up the drying."
Trying to dry grain too quickly with heated air can lead to stress that can crack kernels, he said.
Repeated exposure to moisture and then redrying also leads to broken grain, he said, and the intent is to dry grain evenly throughout the kernels to get the best milling quality.
Gardisser said farmers who have their own drying and storage facilities should keep the facilities clean. Dirty fan blades can reduce air movement by 50 percent, he said. Lights located near fans can attract insects that can foul fan blades, he cautioned.
Gardisser also advised farmers to cover fan openings, when fans are not in use, to prevent moisture from getting to the grain.
He also advocates mechanical stirring devices to prevent grain from coning inside the bins and to distribute debris, which usually accumulates and compacts in the center of a bin, blocking air movement. Mechanical stirrers can pay for themselves quickly from reduced drying costs, he said.
Gardisser said farmers shouldn’t pump air when temperatures fall below freezing, because moisture within kernels will expand – placing stress on the kernels and resulting in cracking or breakage.
Condensation inside grain bins is inevitable after a cold front passes, he said, and that moisture will have to be removed, but he cautioned against using heated air because it is not necessary, will cost more and could lead to grain damage. He emphasized the keys to drying are the use of high air volumes and the use of air of lower moisture content than the grain; air quantity; and air quality.
The University of Arkansas expert recommends using a sling psychrometer to determine relative humidity, a simple manometer to measure air pressure produced by blowers, a thermometer probe, an accurate moisture meter and a grain probe.
Details about using those tools and other advice are provided in Gardisser’s booklet "Rice Drying on the Farm," available from Dr. Johnny Saichuk, LSU AgCenter rice specialist.
Also at the seminar, Dr. Michael Salassi, LSU AgCenter economist, told farmers owning their storage bins allows them to hold their crop and sell when prices typically peak in February. But the cost of drying and storage is a factor that also has to be considered, he said.
In addition, Dr. Jack Baldwin, LSU AgCenter entomologist, said protective chemicals such as Reldan are available to treat rice to ward off stored grain insects.