Wet Grain Piles Deteriorate Rapidly
Rain could cause rapid deterioration in uncovered outdoor grain piles.
A 1-inch rain will increase the moisture content of the top 1 foot of wheat by about 8 percentage points, from 13 to 21 percent, if the top foot of the wheat absorbed all the water, he says. Wheat at 21 percent moisture will deteriorate quickly.
The depth that the water will penetrate into the pile depends on the rain intensity and quantity. A slow, light rain primarily will be absorbed by grain on the pile surface, while a more intense rain event will soak further into the grain.
It is encouraged for producers to probe the grain piles to determine the extent of moisture intrusion and the grain moisture content. Grain may be wet only to a depth of a few inches or several feet. Also, producers should measure the grain temperature in numerous locations.
Do not walk on the pile because the indents become water collection and pile entry points during subsequent rain events.
Water will not run off a recently created pile. About 40 percent of the grain pile is empty space, so water will run into the pile easily. Rain will not run off the pile until the top surface has crusted due to grain deterioration.
Pour water from a pail or a hose onto a pile without a crust and observe how much runs off the pile to check the theory of a pile shedding water.
The amount of moisture in a grain pile is a concern to producers because the allowable storage time is only about 11 days for wheat with 21 percent moisture content at 70 degrees and only about five days at 80 degrees. The wet wheat needs to be dried quickly to minimize deterioration.
Losing a foot of wheat due to deterioration is very expensive at today’s wheat prices. For example, a foot of wheat in a pile 10 feet high and 43 feet in diameter is about 30 percent of a 3,900-bushel pile. Losing a foot of wheat from a pile 40 feet tall and 170 feet in diameter is only about 8 percent of the pile, but it still is about 20,000 bushels.
Wind blowing on the surface of the pile will dry some of the wheat near the surface, but the air will flow over the top of the pile more easily than go through the grain, so the drying effect of the wind is confined to near the surface.
Wheat will dry faster in a swath on the ground than in a pile because a swath is much more porous. Also, a swath has straw to help wick away moisture and it isn’t very thick, which allows the wind to push air through it.
Although the sun shining on the pile will help dry the surface, it also will increase the grain temperature.
The sun will not shine on the north side of the pile.
Aeration pushing air up through the pile will help control the amount of temperature increase occurring due to grain heating but will not create enough airflow to dry the grain. However, without aeration, grain temperatures will increase, which will increase the rate of deterioration.
