1, cash crops, which are mainly used as industrial raw materials with strict requirements on natural conditions, complex technical requirements and high economic value of products, are also called "technical crops" or industrial raw materials crops.

2. Cash crops include cotton, oilseeds, hemp, silkworm silk, tea, sugar, vegetables, tobacco leaves, fruits and medicinal materials.

3, food crops, refers to the purpose of harvesting mature fruits, after hulling, grinding and other processing procedures and become the basic food for human beings. Mainly divided into: cereal crops, potato crops and bean crops.

4. The main food crops are: wheat, rice, corn, oats, rye, barley, millet, sorghum and highland barley, among which wheat, rice and corn account for more than half of the world's food.