During recent years, the use of high moisture grain has become more popular. This is due to the increased costs of handling and dry feed grains. For cattle feeders in particular, storing grains as high moisture. This is one practice that can improve their competition. Using high moisture grain allows greater opportunity to design a system that will minimize harvest, storage and feed processing costs. Grains such as wheat have been stored as high moisture, but corn is the principal high moisture grain stored. High moisture corn can be processed and stored as whole shelled corn, ground shelled corn or ground ear corn.
Deciding whether to dry or store high moisture corn, you need to consider the following advantages and disadvantages. The advantages of high moisture corn are: Costs incurred during artificial drying are eliminated. High moisture corn can be harvested two to three weeks earlier than corn harvested for dry storage. Dry matter losses from field and harvesting can be decreased by 3 to 8 percent for corn harvested at 25 to 30 percent moisture compared to corn harvested for dry storage. Greater potential exists for the use of higher quality residues.
There are many disadvantages of high moisture corn. Some include: Loss of some marketing flexibility compared to dry corn. Additional processing equipment may be needed. Additional storage facilities may be needed. Spoilage can be a problem and storage losses may be higher than for dry corn if high moisture corn is not properly ensiled and fed at adequate rates. Also High moisture, fermented corn may require better bunk and feeding management than dry corn.
Corn is considered mature when it will reach the maximum quantity of dry matter. Most corn kernels are dry matter until moisture decreases to 30 to 35 percent; although, some may be mature at 40 percent moisture. Postponing harvest to decrease corn moisture does not increase yield or energy per acre and often increases field losses. Corn kernels that have started to dent have about 50 percent moisture and are in a medium soft stage, but are not mature. Twelve to 16 days are usually needed to reduce kernel moisture from 50 to 40 percent. Moisture in corn should allow for easy harvesting, lower field losses, excellent packing, proper fermentation and more desirable animal performance. Moisture content that best satisfies these requirements occurs shortly after maturity is reached. An acceptable range for corn moisture content is 22 to 28 percent. At this stage corn loses about 1/2 to 1 percent moisture per day in the field.
Field losses at harvest can be affected by corn moisture content. Harvesting and handling becomes easier as moisture content falls, but ear droppage and downed stalks increase due to wind, stalk rot, and insect damage. These losses can be minimized with proper machinery adjustment, and beginning harvest when corn is around 30 percent moisture and finishing before corn is less than 24 percent moisture.
High moisture corn storage methods are commonly used for high moisture corn. They consist of two main types. Ground high moisture corn is normally stored in bunker, whereas whole high moisture corn is stored in upright oxygen limiting structures. Ground or coarse rolled corn can also be stored in upright structures. The large bagging systems that have been primarily used for storing can also be used for high moisture corn storage.
Every bushel of corn you save by careful operation of your combine adds to your profit per acre. Losses as high as 20 bushels of corn per acre have been measured behind a poorly adjusted combine operating in weedy or severely lodged corn. Harvesting losses cannot be completely eliminated, but they can be reduced to 1 to 2 bushels per acre if you take time to check the performance of your combine.
Preharvest losses are ears that drop from the stalk before harvesting begins. These losses are not causes by the combine, but they can be reduced by harvesting early.
Harvesting losses can be separated into four types of losses. Gather losses occur at the front of the combine, and consists of ears missed or dropped by the machine and loose kernels shelled by the stalk rolls in the cornhead. Cylinder and separating losses will be found on the ground behind the combine. Cylinder losses are kernels attached to pieces of cob that were not shelled by the combine cylinder. Separating losses are loose kernels that were not shaken out of the cobs and husks and were lost over the back of the combine.
The easiest way to measure loose kernel losses is to use a rectangular frame enclosing 10 square feet. Every 20 kernels of corn found within the frame is approximately equal to 1 bushel per acre loss. Make the frame out of No.9 wire or 1/8-inch rod and carry it on the combine. The width of the frame should be the same as the width of your corn rows, and the length of the frame is listed in table 2.
To measure losses, stop your combine well in from the edges of the field, disengage the header drive, raise the header, and back up 15 to 20 feet. Measure or pace off an area of 1/100 acre on the harvested rows behind your combine, gather all missed ears of corn within this area, and count the number of equivalent 3/4-pound ears to determine total ear loss.
If total ear loss is high, mark off an area of 1/100 of an acre in the standing corn in front of the combine, gather all missed ears, and count the number of equivalent 3/4-pound ears to determine preharvest loss. Subtract preharvest loss from the total ear loss to determine machine ear loss.
To measure kernel losses, place the rectangular frame over the first harvested row behind the combine. Carefully remove the stalks, husks, and leaves, and count the kernels attached to pieces of cob and the loose kernels within the frame, Record each count separately. Then flip the frame over onto the next row and count the kernels. After kernels are counted from all the rows being harvested, divide the total number of kernels attached to cobs by the number of rows, and then divide the answer by 20 to find cylinder loss. Divide the total number of loose kernels by the number of rows, and then divide the answer by 20 to find the total loose kernel loss. This will be the sum of stalk roll shelling and separating loss.
If total kernel loss is high, place the frame over the first harvested row in front of the combine, just ahead of the drive wheel tracks. Carefully remove the stalks and leaves, count all loose kernels within the frame, and divide the answer by 20 to find the stalk roll shelling loss for that row. Flip the frame over and count the kernels in the next row. Record the count for each row separately, because only one row on the cornhead may be out of adjustment and may be shelling more corn that the others. After counting losses for all rows, add them and divide by the number of rows to find an average stalk roll loss. Subtract this average loss from the total loose kernel loss found behind the combine to determine separating loss.
Adjustments and Operating Practices to Keep Losses Low Keep your combine in good repair. Keep chains properly adjusted and belts tight. Lubricate bearings and roller chains when they’re warm to get better lubricant penetration; oil roller chains in the evening so excess oil can drip off overnight.
Properly governed engine speed is essential for proper separator action. The recommended speeds for the engine and threshing cylinder are in your operator’s manual. Check these speeds when the engine is operating at temperature.
Plant your corn in rows equal to the row spacing of your cornhead. In the survey, harvest losses were more than 1 bushel per acre higher for combines with a cornhead row spacing 2 inches different from the width of the corn rows. If you have a combine with a 38-inch cornhead, plant your corn in 38-inch rows, not 36- or 40-inch rows.
Adjust stalk roll speed and spacing to snap ears about one-half to two-thirds of the way up the snapping bars. Snapping bars should be spaced narrower in front than in back to prevent wedging. A spacing of 1 1/4 inches in front and 1 3/8 inches at the back will be satisfactory under most conditions. If a wider spacing is used, small ears will wedge between the snapping bars and shelling losses will increase. Be sure stalk roll spacing and snapping bar spacing are the same on all rows.
Adjust gathering chains so the flights are opposite each other and extend about 1/4 inch beyond the snapping bars. Keep trash knives adjusted close to the stalk rolls.
Gathering snouts should just touch the ground under normal field conditions. If corn is badly lodged, slow down and let the snouts float on the ground. Under good field conditions, maintain a field speed that uses much of your combine’s capacity. Avoid overloading. Check chaffer, sieve, and fan adjustments and reduce travel sapped if necessary to keep separating losses under 0.3 bushels per acre. Watch for ears lost at the header and reduce travel speed if more than one ear per 1/100 acre is dropped. Travel speed greater than 4 miles per hour may lead to excessive losses. Slower field speed is required for heavy crop conditions.
Adjust cylinder-concave clearance according to your operator’s manual and adjust cylinder speed to fit corn conditions. Cylinder or rotor speed should be just high enough to adequately thresh corn without excessive damage. Try not to break cobs into more than three or four pieces for better separating. If cob breakage is severe, increase the rear cylinder-concave spacing 1/8 inch and then if necessary increase cylinder speed to improve shelling.