1, can make full use of soil nutrients. 2, is conducive to the prevention and treatment of pests and diseases.

Scientific crop rotation should pay attention to grasp the following principles:

1, absorption of soil nutrients, root system depth of different crops with each other. Such as consuming more nitrogen fertilizer leafy vegetables, consuming more potash root vegetables and consuming more phosphorus fertilizer fruit vegetables; deep-rooted root vegetables, eggplant and fruit, melons (in addition to cucumbers) and shallow-rooted leafy vegetables, green onions and garlic, etc. Crop rotation.

2. Crops that are not contagious to each other rotate with each other. Vegetables of the same family are often infected with the same pests and diseases, the development of crop rotation program should, in principle, try to avoid the same vegetable crop.

3, improve the soil structure of the crop rotation each other. In the crop rotation system with appropriate legume, grass vegetables, crop rotation, increase organic matter to improve the soil's granular structure.

4, pay attention to different vegetables on the soil pH requirements. Such as beans, kale, potatoes, etc. After planting, can increase soil acidity, while corn, pumpkin, etc. After planting, can reduce soil acidity, so the soil acidity sensitive onions, etc. As corn, pumpkin after the work can be a higher yield, as the kale after the work will be reduced.

5, to take into account before and after the crop, do not miss the agricultural time.