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close this bookBetter Farming Series 15. Cereals (FAO Better Farming series, 1977, 51 p.)
close this folderMaize
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View the documentTraditional maize growing
View the documentHow to increase maize yields

How to increase maize yields

Choosing the seeds

If you want a good harvest, you must sow good seeds.

You can choose seeds from your own crop. When you harvest, choose the biggest cobs. Keep these cobs. For sowing, take only the best- shaped grains from the centre of the cobs. If you choose your seeds in this way, you will have a better harvest. Seed dressing is also useful.


The finest grains from the centre of the cob are chosen

But yields become smaller if you sow every year seeds from last year's crop. After a few years, the maize loses its good qualities. So you must buy new seeds.

· The research stations have improved varieties of maize which produce very good seeds.

Several varieties of maize are grown at the research stations. The female flowers of one variety are fertilized with the pollen from the male flowers of another variety to produce hybrids. Otherwise, selection breeding is carried out within the same variety.


Pollen from the male flowers of one variety fertilizes the female flowers of another variety


The little bag prevents pollen from fertilizing the female flowers of the same plant

When the female flowers of one maize variety are fertilized by pollen from the male flowers of another maize variety, this is called crossing. The flowers fertilized in this way produce a new variety of maize called a hybrid, which is better than the two original varieties. But after several years of growing maize from the previous crop's seeds, this new variety loses its good qualities. So new seeds have to be bought.

Crossing two varieties may also result in new varieties that are more resistant to disease.

· Preparing the soil

Maize needs fine earth, without clods, a loose soil, in order to develop its root system. Tilling with a plough loosens the soil. The clods are broken up with the harrow.

HOW TO SOW

Sow your maize at the beginning of the rainy season. Sow in rows, leaving 80 centimetres between rows. Put 3 to 4 seeds in one hole, leaving 50 centimetres between holes.

Make each hole 7 centimetres deep and cover the seeds with a little earth. Like that, the seeds have more protection against rats and birds.

HOW TO LOOK AFTER MAIZE

· Weeding is very important.

This work can be done better and more quickly with an animal- drawn cultivator.

Weed for the first time 15 days after sowing.

Pull out the smallest seedlings from holes where all the seeds have come up; leave only the largest seedling.

Weed for the second time when the plants are 50 centimetres high. When you weed, also earth up the plants. After earthing up, the plants will have more adventitious roots, and the maize will be more resistant to drought. The maize will be better nourished.

· Manure and chemical fertilizers

Organic manure and chemical fertilizers cannot be used well and it is not profitable to apply them:

· if the sold is not well prepared,
· if the seeds are not well chosen,
· if sowing is not done at the right time, in rows and at a good density,
· if the weeds are not removed whenever they grow,
· if the crop rotation is not good.
· Different manures and fertilizers have to be applied:
· according to your crop rotation.

Different plants do not all take the same amount of each mineral salt out of the soil. Before sowing maize, you must therefore give back to the soil the mineral salts taken out by the previous crop. These mineral salts are contained in the fertilizers.

· according to the region.

The soils of different regions do not all contain the same amount of each mineral salt. They must therefore be given different fertilizers.

For example:

If a soil is poor in nitrogen, the tips of the young leaves turn yellow. You must therefore add nitrogen to the soil.

You can use:

· organic manures

These are animal manure and green manure.

Organic manure improves the structure of the soil. Plants grow better in a soil of good structure, and the chemical fertilizers are used better. Organic manuring should therefore be done at the beginning of the rotation, that is, before growing the first crop on a field.

· chemical fertilizers

Maize needs above all nitrogen.

The nitrogen fertilizer most often used in Africa is ammonium sulphate.

But maize also needs phosphate and potassium.

Ask the extension services for advice. They will tell you how much fertilizer to apply to your maize field.

For example: At Bouake (Ivory Coast), the following fertilizers are applied before sowing one hectare of maize: 100 kg ammonium sulphate, 100 kg dicalcium phosphate, 50 kg potassium chloride

After the first cultivation, another 100 kg ammonium sulphate may be added. Be careful not to put any fertilizer on the leaves; the fertilizer may burn the leaves.

HARVESTING

Maize can be fed to animals when the plants are still green. In that case, cut the maize when the male flowers begin to go dry. You can also make silage.

If you want to roast the maize cobs, harvest the cobs when the grains are not too ripe.
If you want to make flour, harvest the cobs when the grains are quite ripe.

STORING MAIZE

Maize cobs can be stored in their husks. That way, the cobs keep better.

They can also be stored without their husks, but then the cobs may be attacked by insects. There are insecticides which kill these insects.


Maize cob in husk


Maize cob without husk