Maize (Zea mays L.) is the most important grain crop in South Africa and is produced throughout the country under diverse environments.
Successful maize production depends on the correct application of production inputs that will sustain the environment as well as agricultural production. These inputs are, inter alia, adapted cultivars, plant population, soil tillage, fertilisation, weed, insect and disease control, harvesting, marketing and financial resources.
In developed countries, maize is consumed mainly as second-cycle produce, in the form of meat, eggs and dairy products. In developing countries, maize is consumed directly and serves as staple diet for some 200 million people. Most people regard maize as a breakfast cereal. However, in a processed form it is also found as fuel (ethanol) and starch. Starch in turn involves enzymatic conversion into products such as sorbitol, dextrine, sorbic and lactic acid, and appears in household items such as beer, ice cream, syrup, shoe polish, glue, fireworks, ink, batteries, mustard, cosmetics, aspirin and paint.
Approximately 8,0 million tons of maize grain are produced in South Africa annually on approximately 3,1 million ha of land. Half of the production consists of white maize, for human food consumption.
Maize needs 450 to 600 mm of water per season, which is mainly acquired from the soil moisture reserves. About 15,0 kg of grain are produced for each millimetre of water consumed. At maturity, each plant will have consumed 250 l of water. The total leaf area at maturity may exceed one square metre per plant.
The assimilation of nitrogen, phosphorus and potassium reaches a peak during flowering. At maturity the total nutrient uptake of a single maize plant is 8,7 g of nitrogen, 5,1 g of phosphorus, and 4,0 g of potassium. Each ton of grain produced removes 15,0 to 18,0 kg of nitrogen, 2,5 to 3,0 kg of phosphorus and 3,0 to 4,0 kg of potassium from the soil.
No other crop utilises sunlight more effectively than maize, and its yield per ha is the highest of all grain crops. At maturity, the total energy used by one plant is equivalent to that of 8 293 15 W electric globes in an hour.