Corn (Zea mays ssp.), also known as maize, is a cereal grain originating from the American continent.  It spread to the rest of the world in the late 15th century and early 16th century. Corn has a very distinct growth form: the lower leaves are like broad flags, 50-100cm long and 5-10cm wide; the stem is erect, 2-3m high, with many nodes. The plant can grow more than 5cm a day. Under these leaves and close to the stem grow the ears. The ears are female inflorescences, tightly covered by several layers of leaves. Commercial plant develops 0-2 ears (average of 0.9 ears per plant).

Corn may be y defined according to its kernel: dent, flint, flour, sweet, pop and pod corn. Except for pod corn, these definitions are based on quality, quantity and pattern of endosperm composition in the kernel. Different types of corn are produced for different purposes, such as sweet corn consumed directly as human food, dent corn for silage as animal food or grains for flour.

Environment

Climate: Corn is an outstanding crop among other summer crops due to its potential to produce large amounts of dry matter.  It is also the most adaptable and variable member of the grass family. Corn can be grown from the tropics to the North Temperate Zone, from sea level to 3500m altitude. The optimal temperature range for growth during daylight hours is 25-33°C, and at night 17-23°C.

Soil: Corn can grow and produce well in different types of soils, from sandy to heavy clay. Soil pH ranges from 6.1 to 7.5. Unlike other cereal crops corn is susceptible to water quality. Corn can be grown in saline soils without yield reduction as long as the electric conductivity (EC) of their saturated extract is up to 1.7 dS/m.

Planting layout

Early planting is critical for achieving higher corn yields. Plants tend to be shorter in earlier planting, which allows higher plant stand, which can result in higher yields.  With later planting, the plants are taller and compete more for light. The optimum plant population and planting date interaction will vary with soil, tillage practice, and location, and hence must be evaluated on an individual basis. Highest yield results from rows of 70 to 100cm apart and seeds spaced 12 to 15cm in the row, which is about 65,000-75,000 plants per hectare.

Water demand

Corn is generally grown in areas with at least 500mm of annual precipitation. For higher yields, additional 300-450mm will be required. The water demand must be met by natural rainfall, or in case of drier areas, by supplemental irrigation. Water stress is critical during support root formation (2-3 weeks from germination) and during pollination and grain development.

Irrigation

Different irrigation methods are used in corn cultivation. The drier the area and lower water quality, drip irrigation has definite advantage