Maize (Zea mays) is an annual grass originating in Central America. It is a tall crop typically 2-3 m, and, unlike wheat, barley and rice, has separate male and female flowers. Male flowers emerge as the tassel from the top of the stem after all the leaves have formed, while the female flowers are found at the base of the leaves on the middle of the stem. After pollination, the collection of female flowers forms the familiar cobs. Most commercial varieties have one or two large cobs.
Commercial varieties of maize in more technologically advanced farming systems are actually ‘hybrids’. These are bred by crossing two dissimilar parent varieties. This means that the offspring are particularly vigorous and high yielding. However, the genetics of hybridization means that the harvested seed cannot be used to grow a successful new crop and farmers must buy a fresh supply of first generation hybrid seed.
Maize is a staple source of carbohydrate in the diet of hundreds of millions of people. It is also a rich source of some B group vitamins. However, as a protein source maize lacks the amino acids lysine and tryptophan, essential for humans and animals.
Maize cropping
Maize (corn) along with wheat and rice is one of the world’s top crops. Maize provides not only the fast-foods of western society - breakfast cereals, sweet corn and popcorn – but also the staple foods for much of the world’s population in developing countries. All around the world, maize grain is a basic livestock feed, and the crop can be cut while still green to make silage. Maize, perhaps more than any other crop, reaches both high and low extremes of sophistication, mechanization and technology in crop production. All farmers, however, need to maximize the yield and quality of their produce, while saving the costs, time and labor needed to grow it. Protecting maize from weeds, pests and diseases is essential to avoiding heavy losses in yields and quality of grain. Weed control is usually most important in maximizing yield.
Where is maize grown?
Maize is grown over a wide range of climatic conditions from tropical to temperate. In warmer conditions two or more crops may be grown in one year, but in cooler temperate climates, although a valuable forage crop, grain will not fully ripen.
How is maize grown?
Maize is a ‘row crop’
Maize can be grown all year round provided there is availability of water (either through rain or irrigation) for the crop to develop. Maize seed is traditionally planted in wide rows about 60 cm apart and 30cm within rows, which enables weed control in the growing crop by mechanical cultivators or hand hoeing. Wide rows are still popular in maize even where herbicides are used.
Double Cropping
Maize is usually grown in rotation with nitrogen fixing leguminous crops, often soybeans which improve the fertility of the soil for the following maize crop, reducing the need to apply nitrogen fertilizer.
