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RSSOctober 29, 2009
Estimating Drying Times for High Moisture Corn and Natural Air
I have received numerous calls from corn producers harvesting high moisture corn well above the recommended 15% moisture content for long-term storage and/or to avoid being docked by the grain merchandiser. Producers with drying bins and aeration fans capable of producing at least 1 cfm/bu are wondering how long it will take to dry their corn to 15% moisture using ambient (unheated) air.
The time to dry corn, or any grain, depends on a number of variables:
When you use FANS, be sure to click on the Crop Selection tab and select the correct crop. Then click on the Fan Selection tab and pick your fan from the list. If your fan model is not on the list, pick a similar fan from another manufacturer. Be sure to change the Bin Diameter and Grain Depth to match your situation. Click the Update Estimates tab then click the Airflow vs Depth Table. To print the Airflow vs Depth Table, click on File in the upper left corner and click on Print Airflow vs Depth Table. |
More information on grain storage management is available on the UNL in Lancaster County Acreage, Farm & Ranch page. |
- The initial moisture content of the grain, %
- The desired moisture content of the grain, %
- The ambient air properties ― temperature and relative humidity
- The airflow through the grain in the bin ― cubic feet per minute per bushel
- Whether the incoming air is heated before passing through the grain
Using a grain drying program, I ran several scenarios to estimate the time it would need to dry corn (see Table 1). It estimated the days to dry corn in a grain bin using natural air and 1 cubic foot per minute per bushel of grain in the bin.
As you can see in Table 1, weather conditions are a huge factor in how long it takes to dry grain.
Tom Dorn
Extension Educator in Lancaster County
Table 1. Days required to dry corn to 15% moisture with 1 cfm/bushel airflow, using natural air drying. Assumes exhaust air has 85% relative humidity. | |||||||
| Air Properties | Initial Moisture (%) | ||||||
| 60°F | 16 | 17 | 18 | 19 | 20 | 21 | |
| Drying Time (days) | |||||||
| 60% | 4.3 | 8.8 | 13.3 | 18.0 | 22.7 | 27.6 | |
| 50% | 3.2 | 6.5 | 9.9 | 13.4 | 17.0 | 20.6 | |
| 40% | 2.5 | 5.2 | 7.8 | 10.6 | 13.4 | 16.3 | |
| 30% | 2.1 | 4.2 | 6.4 | 8.6 | 10.9 | 13.3 | |
| Air Properties | Initial Moisture (%) | ||||||
50°F | 16 | 17 | 18 | 19 | 20 | 21 | |
| Drying Time (days) | |||||||
60% | 5.7 | 11.5 | 17.4 | 23.5 | 29.8 | 36.2 | |
| 50% | 4.1 | 8.3 | 12.5 | 16.9 | 21.4 | 26.0 | |
| 40% | 3.2 | 6.5 | 9.8 | 13.2 | 16.8 | 20.4 | |
| 30% | 2.6 | 5.3 | 8.0 | 10.8 | 13.7 | 16.6 | |
| Air Properties | Initial Moisture (%) | ||||||
40°F | 16 | 17 | 18 | 19 | 20 | 21 | |
| Drying Time (days) | |||||||
| 60% | 6.3 | 12.8 | 19.5 | 26.3 | 33.3 | 40.5 | |
| 50% | 4.7 | 9.5 | 14.4 | 19.4 | 24.6 | 29.9 | |
| 40% | 3.7 | 7.6 | 11.5 | 15.5 | 19.7 | 23.9 | |
| 30% | 3.1 | 6.3 | 9.5 | 12.8 | 16.3 | 19.8 | |
| Air Properties | Initial Moisture (%) | ||||||
30°F | 16 | 17 | 18 | 19 | 20 | 21 | |
| Drying Time (days) | |||||||
| 60% | 8.2 | 16.5 | 25.1 | 33.8 | 42.8 | 52.0 | |
| 50% | 6.2 | 12.6 | 19.2 | 25.9 | 32.7 | 39.8 | |
| 40% | 5.0 | 10.1 | 15.4 | 20.8 | 26.3 | 32.0 | |
| 30% | 4.1 | 8.4 | 12.7 | 17.2 | 21.7 | 26.4 | |
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