The forms of multiple cropping are

There are four forms of multiple cropping: stubble multiple cropping, transplanting multiple cropping, interplanting multiple cropping and regeneration multiple cropping.

(1) Continuous cropping refers to the planting method of sowing the next crop in the same field after harvesting the previous crop alone within one year. Such as planting summer corn or summer soybean after wheat harvest.

(2) Transplanting and multiple cropping refers to the planting method of transplanting the next crop in the same field after harvesting the previous crop separately within one year. Such as transplanting cotton or watermelon (melon) seedlings after garlic harvest.

(3) Intercropping and multiple cropping refers to the planting method of interplanting the previous crop or the next crop in the same field within one year. For example, wheat interplanting corn and wheat interplanting cotton.

(4) Regenerative multiple cropping refers to the multiple cropping form formed by rice and ratooning rice.

Multiple cropping methods in various parts of China:

It varies with latitude, region, altitude and production conditions. Generally, in the season when crops can grow safely, in areas with more than one crop and less than two crops, two-crop interplanting is adopted to overcome the seasonal contradiction between the previous crop and the following crop, or early-maturing and late-autumn crops are planted in summer after harvest in winter.

In North China, which is cool in winter or has poor irrigation conditions, the dry land is mostly wheat-corn, wheat-soybean or spring corn-wheat-millet. It is cool in winter and rainy in summer in Jianghuai area, so wheat-rice double cropping or wheat-cotton intercropping is widely used.

In the warm and rainy provinces south of the Yangtze River and the irrigated Taiwan Province Province, in addition to wheat-rice double cropping, rape-rice double cropping and early rice-late rice double cropping, green manure-rice-rice, wheat-rice-rice, rape-rice-rice triple cropping system is prevalent, and there are three seasons of rice cultivation in southern China. In dry land, barley, wheat and corn (soybean and sweet potato) are mainly double-cropping, and some of them are intercropped with wheat, corn and sweet potato.

Application restrictions of multiple crops

Multiple cropping is mainly used in warm temperate zone, subtropical zone or tropical zone with long growing season and much precipitation (or irrigation), especially in areas with a large population and little land.

The main function is to improve the utilization rate of land and light energy, so that green plants can synthesize more organic matter and increase the annual total output of crops per unit area by prolonging the utilization time of light energy and heat in a limited land area; Increase ground coverage and reduce soil water erosion and wind erosion; Make full use of manpower and resources.