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Agriculture
Maize is an annual crop requiring 110-140 frost-free days. It can be grown in northern regions as a grain crop in continental climates of Canada and Russia, and in the Atlantic climates found in the UK, the Netherlands or northern Germany. Maize grain can be grown as far south as 40º in South Africa, South America and Australia.
Like most other crops, maize does best on deep, well drained, friable and nutrient-rich soils with good levels of organic matter. Because these ideal conditions rarely occur, most maize is grown on less fertile land with added nutrients, particularly plenty of available nitrogen. For successful
germination, the topsoil should be well aerated. Maize does not compete successfully with weeds, especially for the first fifty days after emergence, so commercial growers either use a pre-emergence weedkiller, or genetically modified seed and glyphosate to kill everything except the genetically modified maize.
Maize rarely self-pollinates as it loses its pollen before the female silky growth is ready to receive the male seed; however, a 5% overlap has been known to occur. In calm weather, most pollination is by neighbouring plants.
Unlike sorghum, cassava or millet, maize has few defences against grazing animals. It is believed that this is because there was little domesticated livestock grazing on it in its place of origin in the Americas, and so many
cultivars could develop. However, in Africa, maize has many natural enemies such as elephants and monkeys that can destroy crops.
germination is from seed. It is propagated by planting whole kernels (seeds). Maize should be planted early in the season, as soon as the threat of frost is over. Some irrigation may be necessary, as well as some tilling, weed control and nutrient supplementation. In Europe, where forage maize is now widely grown predominantly for dairy cows, a single cow's winter effluent will fertilise enough maize for two cows in the next winter.
Harvesting varies from 90 to 200 days, depending on climate. Maize is physiologically mature when the grain contains 40-45% moisture, at about seven to eight weeks after flowering. Harvesting can be done manually by snapping off the ears from the stalks without removing the husks. As the seed is not shed, the ears can be left on the plant to dry for as long as six to eight weeks. Machines remove the husks, or a combine harvester can husks and shell the grain. Plant uniformity is essential, as is the ability of the plant to remain standing in the field after maturity without dropping ears. In the absence of pests, it is safe to leave ripe maize cobs on the plant, even after the New Year following the harvest. This often dispenses with more expensive methods of harvesting, drying and storage. If removed from the plant with a moisture content of about 20-25%, the cobs can be safely dried on racks anywhere that allows free air circulation such as above the ground or under the eaves of houses or huts. Drying temperatures should not exceed 45ºC. An economic storage solution is to bin the grain in a silo with plenty of airflow. Silos can be made of steel, concrete, aluminium or brick. Long-term bulk storage may require an insecticide or a fungicide, or both, that does not detract from the feed value of the grain.
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