Maize also widely known as corn is a cereal crop which has been known to Africans since the 1500's and is one of the continent's dominant food crops as the grains are rich in vitamins A, C and E, carbohydrates, and essential minerals, and contain 9% protein. They are also rich in dietary fiber and calories which are a good source of energy.. It is widely grown all over the world and can thrive in a range of agro-ecologocal environments. Corn is used as livestock feed, as human food, as biofuel, and as raw material in industry.
The corn plant is a tall annual grass with a stout, erect, solid stem. The large narrow leaves have wavy margins and are spaced alternately on opposite sides of the stem. Staminate (male) flowers are borne on the tassel terminating the main axis of the stem. The pistillate (female) inflorescences, which mature to become the edible ears, are spikes with a thickened axis, bearing paired spikelets in longitudinal rows; each row of paired spikelets normally produces two rows of grain. Varieties of yellow and white corn are the most popular as food, though there are varieties with red, blue, pink, and black kernels, often banded, spotted, or striped. Each ear is enclosed by modified leaves called shucks or husks.
Commercial classifications, based mainly on kernel texture, include dent corn, flint corn, flour corn, sweet corn, and popcorn. Dent corn is characterized by a depression in the crown of the kernel caused by unequal drying of the hard and soft starch making up the kernel. Flint corn, containing little soft starch, has no depression. Flour corn, composed largely of soft starch, has soft, mealy, easily ground kernels. Sweet corn has wrinkled translucent seeds. Popcorn, an extreme type of flint corn characterized by small hard kernels, is devoid of soft starch, and heating causes the moisture in the cells to expand, making the kernels explode. Improvements in corn have resulted from hybridization, based on crossbreeding of superior inbred strains.
Many parts of the corn plant are used in industry. Cornstarch can be broken down into corn syrup, a common sweetener that is generally less expensive than sucrose; high-fructose corn syrup is used extensively in processed foods such as soft drinks and candies. Stalks are made into paper and wallboard; husks are used as filling material; cobs are used directly for fuel, to make charcoal, and in the preparation of industrial solvents. Corn grain is processed by wet milling, in which the grain is soaked in a dilute solution of sulfurous acid; by dry milling, in which the corn is exposed to a water spray or steam; and by fermentation, in which starches are changed to sugars and yeast is employed to convert the sugars into alcohol. Corn husks also have a long history of use in the folk arts for objects such as woven amulets and corn-husk dolls.
Maize is increasingly used as a feedstock for the production of ethanol fuel. Ethanol is mixed with gasoline to decrease the amount of pollutants emitted when used to fuel motor vehicles. High fuel prices in mid-2007 led to higher demand for ethanol, which in turn lead to higher prices paid to farmers for maize. This led to the 2007 harvest being one of the most profitable maize crops in modern history for farmers. Because of the relationship between fuel and maize, prices paid for the crop now tend to track the price of oil.
PEST & DISEASES
There are several diseases which affect maize depending on the life cycle from it cultivation stage till the storage level. They can account for 20-40% losses during cultivation and 30-90% losses during postharvest and during storage. Maize diseases include Anthracnose, downy mildew, smut, rust, leaf blight, leaf spot, and maize streak virus. Common pest of maize include; Termite, stem borer, ear borers, maize weevils, rodents.
Crop maturity from planting to grain harvest stage takes 4½-6 months, depending on variety, seasonal conditions and time of planting. Harvesting is the single deliberate action to separate the cob from its grown medium, while grain can physically be harvested at up to 25% moisture; this is not recommended as drying costs will be high. Grain should not exceed 14% for storage purpose.
Global cereal demand in 2020 is estimated at 2.1 billion MT and will, for the first time, show a major shift in favor of maize with demand estimated at 852 million MT compared with 760 million MT for wheat and 503 million MT for rice. Thus, global demand for maize in 2020 will increase by 45% (compared with 30% for wheat and 32% for rice). This reflects a substantial growth of 72% for maize in developing countries, and 18% growth in industrial countries. This 72% increase in demand for maize in developing countries compares with only 44% for wheat and 33% for rice.