In agriculture, cultivated plants or crops are usually grouper according to the products for which they ate grown as given below.
Cereals
These plants belong to the grass family. They include maize, rice millet, Guinea corn and wheat. They are grown for their grains which form the bulk of the world's food supply. The grains have a high starch content and contain varying amounts of proteins, oils and vitamins
Legumes
The legumes are an important source of dietary protein. They also supply protein rich fodder for livestock in tropical countries. In addition, legumes replenish soil nitrogen because nodules on their roots contain nitrogen fixing bacteria. This makes them important in crop rotation. Legumes include bean, groundnut, cowpea, soya bean, oil bean, Lima bean and yam bean.
Root crops
They are grown mainly for starch and form the staple food of the people in many tropical countries. They include cassava , yam and sweet potato.
Vegetables
Various kinds of vegetables are grown to supply dietary vitamins and certain minerals like calcium. Examples include tomato, okra, onion , pepper and spinach.
Fruits
Many plants are grown for their fruits which ate rich sources of vitamins, especially vitamins A and V , minerals and sugars most fruits are eaten raw. Examples include orange pineapple, banana, plantain , mango , pawpaw and native pear.
Beverages and drugs
The crops which yield these products include cacao, coffee, tobacco and quinine. The products, cocoa and coffee, are food drinks; tobacco is a stimulant; and quinine is used as a medicine.
Spices
Pepper, ginger, cinnamon and cloves belong to this group. They are used mainly for flavouring food.
Oils
The fruits and seeds of certain plants are rich ain soil. Such oil crops include oil palm, Shea butter, coconut and sunflower.
Forage crops
These are the grasses and legumes that are grown for animal feed.
Latex
When a cut is made on the trunks of certain trees, a milky fluid called late flows out. The rubber tree is grown in tropical countries for its latex which is used to make natural rubber.
Fibres
Plants such as jute , hemp and cotton are grown for their fibres which are used for making ropes and cloth.
