A Special Report

Offered By Farm Progress

Grain Handling & Storage Tips

Drying and storing grain more efficiently

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Contents

Brush Up On Your Corn Harvesting and Grain Management Skills ………..….3

Pick Best Way to Dry Corn..................3

Select Drying Method on Cost, End-use..................5

How Fast Can You Expect Corn to Dry Down?..................6

Prevent a Disaster in the Grain Bin ……..……..9

What if There is an Accident?……………..11

Online Resources for Grain Storing and Drying…………..11

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Brush Up On Your Corn Harvesting and Grain Management Skills A key component of the grain management and marketing equation is storage. Should you store most of

your new crop and wait for a better price? Or, should you aggressively market in the fall? While the

answer isn't the same for every farmer, those considering short- or long-term storage will likely need to sit

down and run the numbers before settling on the most profitable option. That includes considering grain

condition and moisture content, energy costs for hauling and drying, and several other incidentals.

This paper is designed to help producers consider all the elements at work when making grain storage

decisions, offering best tips from Farm Progress' vast universe of grain storage resources to help farmers

squeeze more profit from each acre.

Pick Best Way to Dry Corn

Corn growers face one of their biggest challenges in the fall - drying corn. Make a mistake with drying

corn and you could lose a bin over the winter; mismanage the drying process and you could burn through

a lot of expensive fuel or electricity.

Here are some drying methods for your consideration.

Natural-air drying

Natural-air drying is economical, and there is no “bottleneck” at harvest, since bins are filled at the harvest

rate. Corn at 21% moisture content

can be dried to 15% in about 36 days

during October using an airflow rate

of 1.25 cubic feet per minute, or cfm,

per bushel. Because the temperature

is about 20 degrees F cooler in

November, the drying time increases

to about 56 days, and the final corn

moisture content will be about 18%.

Low-temperature drying

Low-temperature drying is defined as

a natural-air system with the air

heated by 5 degrees F more, which

permits drying during periods of

higher humidity and slightly reduces

drying time. Warming the air by 5

degrees during an average November

permits drying the corn to 15% in

about 52 days using an airflow rate of 1.25 cfm per bushel. Warming the air by 10 degrees in November

would further reduce the final moisture content to 12.5%, and slightly reduce drying time to 41 days.

Layer drying

Layer drying using a natural-air or low temperature system, or NA/LT, permits harvesting limited amounts

of grain at higher moisture content than could be dried in a full bin.

Fans warm the air that passes through them. The amount the air is warmed depends on operating static

pressure, fan type and fan efficiency.

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Temperature increases of 2 to 4 degrees F have been measured at 4 inches of static pressure and 4 to 6

degrees F at 6 inches of static pressure. This temperature increase needs to be included in designing and

managing a NA/LT drying system.

Combination drying

Combination drying utilizes a high-temperature dryer to remove some of the moisture, then uses a NA/LT

dryer to complete the drying. This increases the high-temperature drying capacity by two to three times

and results in high-quality grain.

High-temperature bin drying permits efficiently drying higher-moisture-content grain in a bin faster and

under conditions that would not be possible with a NA/LT drying system.

High-temperature bin batch dryers are simple, but it is difficult to determine the appropriate time to stop

drying so the over-dried grain on the bottom of the bin mixes with the wet grain at the top to achieve the

desired average moisture content after the bin has been unloaded.

Stirring devices are recommended to mix the grain during drying to achieve a uniform moisture content

when the drying air is heated more than 10 degrees F.

High-temperature, continuous-flow

For this method, the bin dryer removes dry grain from the bottom of the bin as it reaches the desired

moisture content. It is an efficient dryer, but the disadvantage is that the hottest air contacts the driest

grain, which can damage grain quality if excessive temperatures are used.

High-temp drying

High-temperature drying is effective during periods of high humidity and cold temperatures. Air that has a

very high relative humidity will have a very low relative humidity after it has been heated. Air that is 40

degrees F and 90% relative humidity will have a relative humidity of only 1% after being heated to 180

degrees. The energy required to heat air to 180 degrees from minus 20 degrees will be 1.4 times greater

than heating it from 40 degrees. The amount of energy required to heat the air can be calculated using

the formula: Btu/hr=cfm x 1.1 x temperature increase. Partial air recirculation should be considered on

corn dryers to reduce energy costs.

Germination rates drop rapidly as kernel temperatures exceed 120 degrees F. Therefore, maximum

recommended drying air temperature is 110 degrees F for seed. Maximum recommended drying air

temperature for commercial corn in the various types of dryers is: continuous flow and recirculating batch,

200 degrees; column batch, 180 degrees; and bin batch, 120 degrees. Consult the dryer manufacturer’s

drying temperature recommendations.

There is normally about a 40 degree difference between plenum air temperature and average kernel

temperature in a cross-flow dryer. Therefore, a 180-degree plenum temperature should be an acceptable

maximum recommended temperature for drying corn if the average kernel temperature should not exceed

140 degrees. Remember that corn moisture and temperature vary across a high-temperature drying

column.

Dyeration

Dryeration is the process of allowing hot grain from a high-temperature dryer to steep in a bin without

airflow for about six hours, followed by cooling, which removes about 0.25% of moisture for each 10

degrees F the grain is cooled.

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Grain must be moved to a storage bin to mix grain wet by condensation next to the bin wall and on the

top grain surface during steeping with dry grain.

Dryeration increases the drying rate about 60%, increases energy efficiency and reduces kernel stress

cracks.

Cooling grain in the bin increases drying rate about 30%. An airflow rate of 12 cfm per bushel per hour

cools the grain at the fill rate and is required to rapidly cool the grain to minimize condensation near the

bin wall. Condensation during cooling may be a problem unless the corn is cooled to 90-100 degrees F in

the dryer.

Select Drying Method on Cost, End-use

The University of Missouri Extension developed a few online tools to help in determining cost of drying

grain and finding extra storage options.

While market conditions can change rapidly, growers in the fall of 2014 experienced significantly lower

grain prices than those of just two years prior.

Low prices make it critical to keep costs and waste low, said Joe Zulovich, University of Missouri

Extension engineering specialist. Lower prices mean farmers must calculate whether and how to store

on- or off-farm, and the cost of drying

and transporting to a commercial

facility.

Leaving corn in the field is one way to

store corn, according to MU

Extension natural resource engineer

Frank Wideman and MU Extension

economist Ray Massey. Some

studies show minimal losses when

corn is left to stand in the field for

later harvest, Wideman says. In years

where corn crops are forecast to be

large and prices low, storing in the

field for a time may be an economical

choice.

According to Zulovich, if selecting an

on-farm storage option, there are several choices—conventional grain bins, storage bags or temporary

flat storage in modified buildings or well-maintained covered piles.

Some farmers plan to use machine sheds for temporary storage, but the sheds cannot hold grain safely

without being retrofitted with grain storage walls inside the building walls. Dry grain can be stored outside

within concrete blocks stacked no higher than three blocks. MU specialists advise providing a granular

base or concrete pad floor, and lining floor and walls with a 6-mil plastic vapor barrier if concerned about

moisture wicking into grain. Cover grain with a tarp. Concrete road barriers and commercial wall barriers

also may be used for outside storage walls. Temporary storage is best limited to two months when there

is no aeration.

Aerated covered piles in well-drained outside areas may allow grain to be stored up to six months. Keep

piles small, low and dry

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How Dry is Dry Enough?

If you have decided to wait until winter to market grain as many do, Purdue University Extension grain

specialist Klein Ileleji says you should dry it to 15% as it goes into final storage.

However, if you are intending to hold out for higher prices and longer storage, you may need to get it

drier. He recommends drying it to 14% if you think you may hold it an entire year.

Some people who hold old crop corn into harvest season can earn a premium when ethanol plants need

corn. However, farmers should watch the size of expected carryover as larger crops (as experienced in

2014) can negate the need to hold on to old-crop.

But, if you're really bearish and think you may have to keep corn in your bin more than a year for

marketing purposes, Ileleji recommends drying corn to below 14% all the way down to 13%. Part of the

reason for dropping moisture lower is to increase the odds that molds and insects won't have an

opportunity to grow inside the bin in corn that is held for longer term storage.

Even if you are just holding corn for delivery in January or February, make sure the corn is truly at the

moisture level you think it is before you quit aerating or drying. Double check moisture readings and be

sure you're compensating for temperature of the grain if your moisture meter doesn't do it automatically,

the specialist says.

How Fast Can You Expect Corn To Dry Down?

To bring corn down by about one percentage point of moisture, it takes 15 to 20 growing degree days or

GDD, says Gregg Brenneman, an Iowa State University Extension Ag Engineer. With normal weather you

can expect corn in early October to dry down about 0.5% to 0.75% per day. This rate will decrease in late

October to less than .33% per day.

Based on these drying rates, corn that

reached black layer stage maturity on

October 1 is expected to drop into the low

20% moisture range by late October and

will require additional drying for long-term

storage or sale.

Basic principles of in-field grain drying

When corn harvesting conditions allow

optimal time for in-field drying, taking full

advantage can reduce on-farm energy

consumption, according to Iowa State

University Extension ag engineer Mark

Hanna.

After corn is physiologically mature, a

black layer forms at the tip of the kernel,

preventing further exchange of nutrients

and water between the kernel and cob.

After black layer formation, temperature and relative humidity of surrounding air are the main contributors

to in-field drying. However, plant morphology also is important. A tight husk restricts air exchange with

corn kernels and controls how much of the ear tip is left exposed.

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How fast or slow can you expect corn grain to dry down on the stalk?

Limited field-drying data suggest daily drying rates may average 1.0% in mid-September, 0.7% in late

September and 0.5% in early October. More importantly, there is wide variation among seasons due to

weather conditions. Days early in the harvest season (e.g., the first week of October) with a strong, dry

wind and air temperatures in the mid-70 degrees F range can produce in-field drying of 1% per day.

Conversely, corn moisture content in the field can remain unchanged for periods of two weeks or longer if

weather is cold and wet. A plan for drying grain artificially is necessary during years with inadequate field

drying conditions. In addition, you

need to evaluate stalk strength

and standability of each field

before leaving the corn to dry in

the field late into the season.

Rate of dry down tied to air

temperature

Research shows that corn dry

down in the field is pretty steady,

and linear, from 40% down to

around 20%, then trails off to very

little field drying after that in most

years. The rate of dry down is

closely tied to air temperature.

The other big factor is when your

field hits "black layer" or

physiological maturity.

The fields that hit maturity in early September will generally dry faster than those that hit black layer mid-

to late-September. Numbers cited by agronomists indicate early maturing corn (Sept 1) will average .8%

loss of moisture per day, while corn maturing around Sept 20 will average a .4% loss per day. Here are

some other common rules of thumb for dry down by time frame rather than maturity date:

Date % loss per day

Sept 1-15 1%

Sept 16-30 .75%

Oct 1-15 .5-.75%

Oct 16-31 .25-.5%

November 0-.25%

What does it cost to dry corn?

Drying costs of $20 to $30 per acre may not be uncommon with corn yields of 100 bushels or more. Of

course, this is dependent on many variables, and the final drying costs may vary greatly from year to

year.

One of the first harvest decisions the producer must make that directly influences cost is what moisture

level at which to start harvesting. Most elevators will want corn near the 15% moisture level to be

considered dry. Corn delivered at higher moisture levels will be charged a drying fee and will also be

subject to a shrinkage discount.

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Drying charges will vary from elevator to elevator. Many can charge 4 to 5 cents per bushel per point of

moisture above 15%. Again, different elevators vary, but shrinkage discounts were generally 1.5% shrink

for each point of moisture above 15%. So, for example, if you hauled in corn at 19% moisture, you would

have a drying charge of 20 cents (4 points x 0.05) and would have a shrinkage discount of 6% (4 points x

1.5%).

On-farm drying should also be considered. Initially, on-farm drying may seem to be more economical than

commercial drying, but many factors have to be weighed. They include costs of storage and handling,

propane and electrical costs, and labor costs.

Another factor is matching the drying capacities of your system to harvest capacity. For example, if you

normally harvest 100 acres of 150-bushel corn daily, your drying system should have a capacity of 15,000

bushels per day.

On-farm drying systems vary greatly with different operations. Some rely on natural air drying where grain

bins are equipped with only full floors and fans with no artificial heat source. A number of on-farm drying

systems will add low-temperature electrical heat sources. The first portion of this paper provided more

information on types of drying.

When considering on-farm drying as an option in comparison to paying for commercial drying, consider

the initial setup costs and depreciation as well as the direct operational costs of the farm drying system.

Calculating on-farm vs. commercial drying costs

The following are calculations – on a per acre basis – of corn-drying costs.

Say the cost of drying a 180 bu. per acre corn crop is about $6 per acre per point of moisture for on-farm

drying. This is figuring 0.02 gallon of LP per point of grain moisture if LP costs are around $1.50 per

gallon. This also figures an electric cost of 0.02kWh per bushel per point of moisture with electric costs of

$0.15 KWh. This cost is energy only and does not include any fixed costs. Fixed costs would be the costs

of the bins, dryers, augers, etc. associated with on-farm drying systems.

The cost to commercially dry a 180 bu. per acre corn crop is about $6.40 per acre per point. This is based

on $0.035 per bushel per point drying cost and 1.5% shrink. The actual moisture loss shrink is 1.18% per

point of moisture, so there is some additional cost of the shrink factor if corn is harvested in the mid-20s

for moisture content.

With these calculations, the cost to dry the corn in your on-farm dryer would be about $30 per acre.

Multiplying 5 points of moisture removed by $6 per acre cost for drying on the farm, it figures out to $30.

Therefore, it is going to cost about $30 per acre to dry a 180 bu. per acre corn crop from 20% moisture to

15% moisture.

It is good advice to check each field for stalk quality and ear retention. Harvest on a timely basis if you

can prevent a 3 to 4 bu. per acre pre-harvest loss versus gaining an extra point of dry down in the field.

Final Tips For More Efficient Grain Drying

•Don't use natural air or low-temperature drying for corn with moisture contents of more than 21%.

•Cool corn to 20-25 degrees F when outdoor temperature average is near or below freezing. Finish drying

in early April.

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•Limit the corn depth to about 20 to 22 feet in bins to obtain the proper airflow rate for drying. An airflow

rate of 1 to 1.25 cubic feet per minute per bushel is necessary to dry the corn before deterioration occurs.

•Turn fans off during extended periods of rain, snow or fog to minimize the amount of moisture the fans

pull into the bin. Adding heat does not help dry wetter corn.

•If high-temperature drying, use the maximum drying temperature that will not damage the corn. That

increases the dryer's capacity (bushels dried per hour) and reduces energy use. Removing a pound of

water will require about 20% less energy at a drying air temperature of 200 degrees F than at 150

degrees F.

•To prevent corn from scorching or browning during drying, limit dryer temperatures. Temperature

reductions likely will need to vary for corn from field to field.

•Another way to reduce the heat damage potential is to dry corn to 20% moisture content instead of 15%.

Evaporative cooling still occurs at the higher moisture content, and the kernels will not be exposed to the

heat as long when corn is dried to the higher moisture content. This also reduces stress cracks and

kernel breakage.

•Use combination drying to reduce heat damage. Dry corn at 28% moisture content to 20% using a high-

temperature dryer and store it for the winter, then dry it to storage moisture in the spring using natural air

drying or a high-temperature dryer.

•Use in-storage instead of in-dryer cooling

to boost the capacity of high-temperature

dryers 20 to 40%, reduce the risk of stress

cracks and remove about 1 percentage

point of moisture. Start cooling immediately

after transferring the corn from the dryer to

the storage bin to reduce the condensation

potential. To further reduce condensation,

cool the corn to about 90 degrees F in the

dryer before placing it in storage.

•Remove debris that accumulates during

drying. It is more critical when outside air

temperatures are cold because

condensation can develop on the dryer,

creating a wet surface where debris can

collect. The debris may reduce airflow through the dryer, decreasing the dryer's capacity and creating a

fire hazard.

Prevent a Disaster in the Grain Bin

You may have decided on commercial storage, or moved forward with on-farm storage. But once you

move the corn to the bin, the last element of efficient grain handling is remembering that ensuring grain

quality can not only put money in your pocket, it can keep you safe.

There are two types of disasters that can happen inside grain bins. The worst possible is to have one

become stuck in grain and possibly suffocate. The second is to be forced to haul out moldy grain and sell

at a big loss or else dump it if it is in terrible condition.

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The two are linked. Doing a good job now can lessen the chances of having to get inside and because

there is spoiled chunks blocking the unloading auger opening when it's time to haul grain out.

Klein Ileleji, Purdue University Extension grain specialist, says the as grain comes in from the field, the

important thing is to dry it down to the proper level.

Some people are under the mistaken impression that if they put grain into a bin at 23% and run large

aeration fans to move air through the grain, as it cools down the grain will cool down, and they can keep it

until next winter. Some even believe it will come out at 15% after that process.

Ileleji says that isn't true. If you put 23% gain in a bin and don't dry it but do aerate it, you're likely going to

have spoiled grain when it's time to unload it. Spoiled grain often means clumps of grain, which means

blocked auger openings. That means a

temptation to enter the bin with an auger

running. That's worse than a bad idea – it's

setting the stage for a deadly mistake, he

notes.

Mountains don't belong in the grain bin

If you wind up with a miniature Mount Rainier

inside your grain bin, then you did something

wrong.

Fines in the middle of the bin can set up such

situations, especially if the grain is not dried or

cooled properly. Fines typically settle in the

middle of the bin. That's why it's important to

core a bin. If it's a big bin you may want to

core it more than once as you fill the bin.

Coring and taking out the center section with fines and broken kernels helps, but it still doesn't guarantee

that problems won't develop inside the grain mass. It takes careful monitoring to do that. If you don't have

sensors inside the bin then it may mean turning on fans at regular intervals and smelling the air that

comes out to make sure it doesn't smell moldy.

Simple, inexpensive safety techniques

If you do find yourself in a situation with clumped grain, never walk on or down the grain to make it flow,

says Karen Funkenbusch, University of Missouri Rural Safety and Health specialist.

Grain may become crusted on top and might look stable, but the "bridge" might be formed over a large air

pocket that will serve as a deadly tunnel in which a person can be sucked into and suffocated within

seconds.

It costs only seconds to think about safety. The cost for a few extra kilowatts is small; the savings are

priceless, she says.

One of the best investments farmers can make is using locks on bin doors and hatches to prevent

unauthorized access, using body harnesses with anchored lifelines if entering from a level at or above

stored grain, and first and foremost, always disconnect and lock out all power equipment such as augers

before entering bins.

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Lastly, she suggests having a trained observer outside the bin. This person can act as a contact with the

person inside the bin and can call for help if needed.

"Confirm that all safety precautions are in place," she said. "Always avoid entering a grain storage bin if at

all possible, but if you must, follow safe procedures. You can't afford not to," Funkenbusch said.

What If There is an Accident?

•Shut off all unloading equipment.

•Call 911.

•Stop anyone from entering the scene until

trained emergency personnel arrive.

•If the bin has an aeration blower, turn it on

to increase the airflow through the bin to

help the entrapped person breathe.

•Assemble equipment such as front-end

loaders, shovels, plywood for cofferdams

and portable augers for assistance with a

rescue.

•If you should become trapped in a grain

bin or silo, stay near the outer wall and

keep moving. If necessary, you can walk

until the bin is empty or the flow stops.

More safety tips when working with grain bins and silos:

•Stay out of the grain bin if possible.

•Never enter a grain bin when the unloading equipment is on, even if the grain isn't flowing.

•Never enter a grain bin alone. If entry into the bin is necessary, always have at least one observer

outside the bin, and make sure all augers are turned off. One person is to enter the bin and the others

should remain outside in case an emergency occurs. Always use a body harness with a lifeline secured to

the outside of the bin.

•Wear an N-95 respirator when working around the grain, as it keeps 95% of the dust and other pollutants

from the grain from entering into the worker's lungs.

•Don't enter a bin that has automatic unloading equipment without first locking out power to the

equipment.

•Be cautious around out-of-condition grain, including grain caked to walls. Dangers result from molds,

blocked flow, cavities, crusting and grain avalanches.

•Lock doors, gates and discharge chutes of any grain storage units.

•Keep kids out of grain wagons, carts and semi beds.

•Block ladders and egress points (for example a ladder guard) to limit kids' access.

Online Resources for Grain Storing and Drying Information

• Drying cost comparison. To compare the costs of drying options along with field dry-down, use the

ISU Ag Decision Maker tools: Estimating the Cost for Drying Corn; Grain Drying and Shrink Comparison

• Natural air drying. If you're drying with natural (unheated) air, the Natural bulletin from the University of

Minnesota is a great summary of concepts and management.

• Understanding airflow. If you need to estimate airflow in a bin from a given fan, or select a fan for a

new drying or aeration system, use this University of Minnesota website.

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• Reduce energy costs. If you're drying with heated air and want to save some fuel and energy, see

Managing High-Temperature Grain Dryers for Energy Efficiency, from Iowa State University.

• Handling and storage. Use these general resources for post-harvest handling, storage and drying of

crops from the University of Minnesota.

• Grain storage tips. View these great tips and rules-of-thumb for grain storage and drying from the

University of Minnesota.

• Estimate bin capacity. Need to estimate the bushel capacity of a bin? Try this online calculator from

Alberta Canada Agriculture and Rural Development.

• Estimate drying cots. Determine the cost of drying grain with this tool from the University of Missouri.

• Estimate energy costs. To estimate the moisture content to which grain can be dried with unheated

outdoor air, you need the equilibrium moisture content of the air, provided by Purdue University. (Table

located at the end of the report).

•Corn equilibrium moisture content