Maize (Zea mays, L.) is one of the most important cereal crops in the world and ranks the third of most important cereal crops in the world. Also, it ranks the third of the world cereal crops which surpassed by wheat and rice. In the USA maize is considered the king of cereal crops. In Egypt, Maize is essential for human and livestocks consumption as an available source of carbohydrate, oil and slightly for protein. It is required for several industrial purposes such as starch and oil. World average cultivated area of maize reached 385.289 million feddan(feddan = 4200 m2) in 2010; the total production was 844.358 million tons, with an average productivity of 2,191.5 kg grain per feddan. The growing area of maize in Egypt during 2010 year is about 2,305,998 feddan with a total grain yield of 7,041,100 ton. The average grain yield production per feddan was about 3,053.4 kg. Это и многое другое вы найдете в книге Maize Yield as Affected by Periods of Weed Control and Plant Densities (El-Saeed M.M. El-Gedwy,Mohamed El-Sayed Riad Gomaa and Salah Abbas Hassan Allam)