Harvesting and Storing Grains the Right Way (Part 2)
If harvesting is delayed and the physiological maturity has been exceeded, the corn ear will tend to droop. This drooping helps prevent intrusion of water into the ear. Early maturing variety or hybrid can be harvested in 90-100 days from planting, while full season hybrid may be harvested in 105-120 days, depending on the hybrid, field condition and elevation, and climatic condition. In certain cases, early harvesting is recommended to
1. reduce risks of delay in harvesting due to rainy weather;
2. avoid excessive loss of grains in the field due to mechanical handling;
3. prevent kernel germination due to water-soaking caused by excessive rains;
4. prevent further development of ear rot fungi;
5. reduce pest damage such as insects and rodents;
6. prevent dropped ears and lodged plants.
Preshelling drying
A good practice we’ve noted in Central Luzon is the drying of ears prior to shelling. This is something that can maintain grain quality as well as minimize losses due to damaged or injured kernels caused by shellers. The following are some recommended preshelling operations for growers:
1. Dry down dehusked corn after harvest for 2-3 days to bring down the moisture to 18%-21%.
2. Use corn cribs or sundrying.
3. Use mechanical dryer at a drying temperatureiof 50°C-60°C.
There is also a good practice in Cagayan Valley called kulob. After harvest, all corn ear are piled in one side of the farm and covered with plastic or tarpaulin for 2-3 days. In this process, corn grains that connect on the cobs loosen or soften, resulting in ease in shelling.
Tips on shelling
Although the types or models of shellers have something to do also with shelling efficiency, the following tips and/or principles apply:
1. Shelling can be done manually or with mechanical sheller.
2. When using a mechanical sheller, ensure that the moisture content of the grains is 18%-21% to minimize mechanical damage or injury to the corn grains.
3. Shelling corn with high moisture content produces more fine kernels because it requires more aggressive shelling that causes breaking and cracking of grains. These fine kernels cause storage problems because they spoil fast than whole kernels.
4. In manual shelling, you can tell if the corn has the right amount of moisture, and that is when the grains can be easily detached from the cobs. But this is more laborious and time consuming. Some, however, have improvised implements that aid in removing the dry kernels from the cobs. But in general, manual shelling is not practical for bulk harvests.
5. Mechanical shelling is faster, requires less effort, and makes the job easier. In most major corn areas, mechanical sheller is a must and has become a business for some growers and cooperatives.
Drying
1. After shelling, immediately dry the grains to 12%-14% MC to prevent molds or amag that produce aflatoxin and other damaging microorganism during storage.
2. Using sundrying, dry the grains 2-3 days or depending on the intensity of sunlight. It must be distributed evenly on a flat outdoor pavement or plastic or net. Mixing as often as possible will hasten drying time and it will provide uniform drying of the grains.
3. Use mechanical dryer, especially during the rainy season.
4. After drying, check the moisture content of the grains before storing. In the absence of the moisture meter, we can estimate the moisture by scooping with bare hands when slippery or it sound like coin when rubbing against each other.
Proper storage
1. Grains with moisture content of 12%14% are ideal for storage in bags (plastic or jute sacks) or in bulk.
2. Keep the grains in a cool dry place, preferably well-ventilated and aerated.
3. Piling of bags of corn grains should allow air to enter between rows.
4. Make sure that grains and facilities are not contaminated/infested with insects, primarily weevil. Corn weevil can be controlled using the recommended solution.
960 ml of water
40 ml of Pirimiphos Methyl
2 ml of Permethrin
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1,000 kg of corn grains
5. Rows or, piles should be provided with spaces to allow easy inspection of pile.
6. Storage facilities should be free from rodents and birds.
7. Observe strict sanitation within and around the storage facilities.
By Allan C. Nieves