Prepare Grain Bins and Equipment for Harvest

With harvest rapidly approaching, now is the time to prepare grain bins and harvesting equipment to help ensure that grain going into storage will remain in good condition. Don't wait until the middle of harvest to discover that a bin foundation is severely cracked, or find even later that insects from grain that was left in the combine last fall have severely infested a bin of new grain. Proper bin and equipment preparation is a key to preserving stored grain quality.

Harvesting and Handling Equipment: Remove all traces of old grain from combines, truck beds, grain carts, augers, and any other equipment used for harvesting, transporting, and handling grain. Even small amounts of moldy or insect-infested grain left in equipment can contaminate a bin of new grain.

Adjust combines according to the manufacturer's specifications to minimize grain damage and to maximize removal of fines and other foreign material. Equip combines with a straw spreader or chopper to avoid leaving windrows of residue that can interfere with subsequent tillage and/or planting operations. Particularly when harvesting soybeans or small grains with a header greater than about 20 feet wide, a chaff spreader may also be needed for more uniform residue distribution. Be sure that all guards and shields are in place and in good working order.

Bins and Other System Components: Check the bin site, and remove any items or debris that would interfere with safe, unobstructed movement around the bin. Remove any spilled grain and mow the site to reduce the chances of insect or rodent infestation. If necessary, re-grade the site so that water readily drains away from bin foundations.

Inspect bins and foundations for structural problems. Uneven settlement of foundations can cause gaps between the foundation and bottom edge of the bin. This can result in grain spills and provide entry points for water, insects, and rodents. If perforated floors are used, a gap between the foundation and bin will allow air that would normally be forced through the grain to escape from the bin. Small gaps can usually be filled with a high quality caulking compound. If deterioration is extensive, the mastic seal may need to be replaced. Be sure all anchor bolts are tight and not damaged.

Inspect the bin roof and sides, inside and out, for leaks, loose or sheared bolts, rust or other corrosion, etc. Check the roof vents and access hatch, and caulk any cracks at the roofline. Be sure the access ladder is complete and securely fastened to the bin. Repair or replace any deteriorated components.

Most farmers with on-farm grain drying systems will begin harvest when grain moisture content is in the low twenties. A bin of 21% moisture corn with a starting temperature of 75 o F, can lose a market grade in only 3 days if the aeration system breaks down. To reduce the risk of a breakdown after your bins are full, always check electrical systems for corroded connections and frayed wiring before harvest. While inspecting control boxes, be sure to seal any openings where mice could get in. Exposed wiring should be run through waterproof, dust-tight conduit. Avoid kinking the conduit, and make sure all connections are secure. Check fans, heaters, transitions, and ducts for corrosion and damage. Remove any accumulated dust and dirt that will reduce the operating efficiency. Be sure that all connections are tight.

Insect Management: Also, clean bins not being used for storage this year to keep insects from migrating to other bins. In Nebraska , grain is free of insects at harvest time ... but it can become infested by insects living on old grain that is left over in storage bins and harvesting and handling equipment. Ensure that the bins are clean. It is essential to clean bins and equipment before harvest. Use brooms and shop vacuums to clean the grain and grain dust from walls - floors - cracks and seams in the combine and in the grain bin at least two weeks prior to harvest. Never put new grain on top of old.

If long-term storage (over 10 months) is anticipated, consider treating the cleaned bin with protective insecticides at least two weeks before adding any grain. Apply the spray to the point of runoff to as many interior surfaces as possible, especially joints, seams, cracks, ledges, and corners. Also spray outside the bin at the foundation and near doors, vents, ducts, and fans.

Residual empty-bin treatments for wheat and feed grains include: Malathion, cyfluthrin (Tempo), chlorpyrifos-methyl (Storcide, Reldan), pyrethrins (many brand names), permethrin (Hard Hitter), piperonyl butoxide mixed with pyrethrins (many brand names and several different concentrations of active ingredient), silicon dioxide (diatomaceous earth under many brand names), silica gel (several brand names), and Bacillus thuringiensis (BT) subsp. kurstaki (many brands). Pirimiphos-methyl (Actellic) is registered for empty bin treatment for corn and grain sorghum only. Silicon dioxide products, BT products, and Tempo Ultra (commercial applicators only) are labeled for empty bin treatment prior to storing soybeans.

Treating when grain temperature is above 90 o F and grain moisture is above the recommended level for long-term storage will increase the breakdown rate and limit insecticide effectiveness. If grain must be treated when it is warm, it should be cooled with an aeration system as soon as possible. Operation of the aeration system will not remove the protectant from the grain.

After the grain has been leveled in the bin, an insecticide should be applied to the surface to form a barrier to prevent infestations. A surface treatment (topdress) should be applied to all grain. Insecticides labeled for surface applications are:

malathion on corn, wheat, oats, rye, barley, sorghum, and sunflowers;

chlorpyrifos-methyl (Storicide, Reldan) on wheat, oats, barley, rye, sorghum, and sunflowers;

pyrethrins plus piperonyl butoxide on corn, wheat, oats, barley, rye, sorghum, and sunflower;

Bacillus thuringiensis (Dipel, Top-Sideside and others) a biological control compound, on corn, soybeans, wheat, oats, barley, rye, sorghum, and sunflowers;

Pirimiphos-methyl (Actellic) on corn and sorghum;

Silicon dioxide (Diatomaceous Earth) - Recommended application of D.E. products include treating the first loads of grain in the bottom of the bin and the last loads at a rate of 1-2 lbs./1000 bu. In 1991, diatomaceous earth was approved for insect control in bulk grain. Diatomaceous earth kills insects with its abrasive qualities and does not leave unacceptable pesticide residues as do some contact insecticides. Diatomaceous earth is now acceptable as an additive to grain as long as its presence is written on the label of the submitted sample. If diatomaceous earth is identified as an unknown foreign substance in an inspection, the grain can be labeled as sample grade, the lowest designation. Consequently, it is advisable to identify the diatomaceous earth when the grain is submitted for grading.

The Indian meal moth is a common problem in Nebraska stored grain, including soybeans. The moth itself does not feed on the grain, but the larva is a surface feeding insect that will infest the top foot or so of the grain mass. It may also be found in perforated floor or door areas. It is resistant to control with malathion. If this insect is a problem, other surface treatments will have to be used. The biological control compound Bacillus thuringiensis (Bt) is labeled for control of the larvae of this insect (but will not control other insects that may infest stored grain) and could be used with other materials. In some areas, Indian meal moth resistance to Bt is being reported, so inspections are critical in maintaining stored grain quality. Dichlorvos strips (Vapona) are labeled to be used in the space above all stored grains for the control of flying insects, including adult Indian meal moths. One strip per 1,000 cubic feet of air space above the grain should be used and changed every 6 to 8 weeks. Actellic and Diatomaceous Earth may be used for all insect problems including Indian meal moth.

Two factors under the control of the farmer that have a direct bearing on the quality of grain coming out of storage are the moisture content and temperature of the grain in storage.

A good goal for corn would be to dry to 15%, and for soybeans dry to 13% moisture content as soon as possible following harvest. After the grain has reached the desired storage moisture content, move at least one (preferably two) cooling zones through the grain to remove field heat or dryer heat as soon as possible. The initial goal is to bring the grain down to 50-55 o F.

Then, plan to move one cooling zone per month through the grain until it is cooled to between 30 o F and 40 o F. This will effectively prevent insect activity in the grain since nearly all insect activity stops at temperatures below 50 o F. Getting all the grain to a uniform temperature will also help prevent convection currents from forming in the grain, which can result in the development of a wet spot in the top center of the bin.

Even after you get grain dry and cold, don't forget it. It should be checked and probed with a temperature probe at least once a month (twice a month is better) while in storage. If the temperature probe shows more than a 10 to 15 degree temperature difference between the sidewall and the center of the bin, the aeration system should be operated until the entire grain mass is a uniform temperature. Pushing a temperature front through the grain could take from one to several days - depending on the size of the fan relative to the number of bushels in the bin.

After probing the grain to check the temperature... start the aeration system and note the temperature and smell of the air coming through the grain. If you detect a musty smell or if moisture condenses on the bin roof, the aeration system should be operated and if you have stirring devices in the bin, run them a round or two to help bring the grain mass to a uniform moisture content and temperature.

In summary, the secret to having good quality grain coming out of storage is to store good quality grain in the first place - harvest it with clean equipment - put it in clean bins - dry it to a safe storage moisture content as soon as possible after harvest - then cool the grain to prevent insect and mold activity - finally, keep the temperature uniform throughout the grain mass by periodic aeration - and check on the condition of the grain at least monthly.

Inspect grain at least once a month in winter and every two weeks in the summer. If problems are detected, they need to be evaluated and corrected as soon as possible. This may include cooling with aeration, further drying, or fumigation for insect control.

David P. Shelton, Extension Agricultural Engineer, University of Nebraska Haskell Agricultural Laboratory; Tom Dorn, Extension Educator, Lancaster County; and Keith Jarvi, Extension Assistant Integrated Pest Management, Northeast Research and Extension Center

Fall Scouting for Conservation Practices

With corn and soybean harvest rapidly approaching, and most field scouting winding down, this is an excellent time to scout and begin planning for conservation practices that could be implemented or installed later this fall or next spring. These practices may include field borders, grassed waterways, water and sediment control basins, windbreaks, and/or conservation buffers.

The combine cab offers an excellent vantage point to note where channels have developed in the field from the concentration of runoff water. These rills generally develop in the same places each year - they get filled in by tillage in the spring, re-develop during the growing season, get bounced over by the combine during harvest, and the cycle is repeated the following year. Consider installing grassed waterways in these areas. Erosion will be reduced and the possibility of equipment damage lessened.

Grassed field borders can provide a convenient location for unloading combines into trucks or grain carts, or for turning planters and other equipment around. Controlling field traffic in this manner can greatly reduce the likelihood of developing a compaction problem within the field. Field borders can often be used to eliminate crop rows that would otherwise be planted up-and-down hill, further reducing soil erosion.

Water and sediment control basins are generally used where gully erosion is a problem and a grassed waterway cannot be installed or maintained because of large volumes of runoff water. They are also used when runoff and sediment from up-slope areas cannot be managed and damage to down-slope areas or other practices will occur. Basins must be cleaned periodically to remain effective.

Conservation buffers placed along the edges of streams or other water bodies can serve as a last line of defense for sediment and other pollutants that might enter the water. They are very effective at trapping sediment, and enhance the infiltration of runoff water. Buffers also improve safety by keeping equipment away from the edge of the stream. Buffers can also provide excellent habitat for pheasants, songbirds, and other wildlife. When planted to trees, a buffer may be able to provide income for future generations.

A number of programs such as the Continuous Conservation Reserve Program are currently available to assist landowners with the adoption and maintenance of many different conservation practices. Check with the local Natural Resources Conservation Service or Natural Resources District office to determine what programs are available for your land. Conservation is a good investment, and this fall is an excellent time to begin or increase that investment.

David P. Shelton Extension Agricultural Engineer, University of Nebraska , Haskell Agricultural Laboratory