In which dynasty did double-cropping rice first appear? When is the sowing and harvesting time?

Double cropping rice is a rice farming system in which two crops of rice are planted and harvested in the same rice field in a year. According to its different cultivation methods, it can be divided into double cropping rice, intercropping rice and mixed rice, which has a long planting history in China. So, in which dynasty did double-cropping rice first appear? When is the sowing and harvesting time?

In which dynasty did double-cropping rice first appear?

It was first recorded in the Book of Mountains and Seas in the 3rd century BC. It is generally believed that "double-cropping rice" and "remature rice" often mentioned in ancient books include ratooning rice, mixed rice, intercropping rice and continuous rice, reflecting the diversity of the absence system of rice cropping in China. The emergence of double-cropping rice plays a very important role in making full use of natural resources and labor resources and increasing grain production.

Second, when is the sowing and harvest time of double cropping rice?

Double-cropping rice began to plant early rice seedlings in mid-late May, and early rice was harvested in mid-late July, followed by ploughing paddy fields and transplanting late rice seedlings, to finish planting before the Beginning of Autumn of the lunar calendar, to harvest late rice in November, and to finish harvesting before the frost fell. Single-cropping rice is planted every year from mid-late June to early July, and harvest begins in mid-late October. The yield per mu of single cropping rice is higher than that of double cropping rice, but the total yield of single cropping rice is much lower than that of double cropping rice.

3. Planting methods of double-cropping rice

1. Land preparation

Before planting rice, the soil of the rice field must be turned over and softened. This process can be divided into three periods: rough ploughing, fine ploughing and leveling. In the past, animal power and ploughing tools, mainly buffalo, were used to prepare the land, but now machines are used to prepare the land.

2. Raising seedlings

Farmers first cultivate seedlings in a certain field, which is often called a rice field. After sowing rice seeds, farmers mostly sprinkle a layer of rice husk ash on the soil. In modern times, special seedling centers use seedling boxes to make rice seedlings grow. Good rice seedlings are the key to successful rice cultivation. When the seedlings grow about eight centimeters high, they can be planted.

3. Transplanting rice seedlings

Carefully insert the seedlings into the rice fields in an orderly manner. The traditional method of transplanting rice seedlings uses ropes, markers or transplanters to mark the rice fields. When transplanting rice seedlings by hand, a seedling splitter is worn on the thumb of the left hand to help farmers separate the seedlings and insert them into the soil. The climate of transplanting rice seedlings is very important, such as heavy rain will damage the seedlings. In modern times, there are many transplanters to transplant rice seedlings, but in the rice fields where the land is undulating and the shape is not square, manual transplanting is still needed. The seedlings generally run north-south. There is also a more convenient way to throw seedlings.

4. Weeding and pest control

When the seedlings grow, they have to be taken care of at all times, and weeds are pulled out, and sometimes pesticides are needed to get rid of pests (such as Oncomelania hupensis).

5. Fertilization

When the seedlings are high and grow the first rice stem, it is called the dividing stage, during which fertilizer is often needed to make the rice seedlings grow healthily and promote the fullness and quantity of spike rice in the future.

6. Irrigation and drainage

Rice depends on this procedure. If upland rice is a dry field, the process of irrigation and drainage is different, but it is generally necessary to strengthen water irrigation after transplanting, when young ears are formed, and at heading and flowering stage.

7. Harvest

When the rice ear is hanging down and golden, the harvest can begin. In the past, the farmers cut it off with a sickle, then tied it up, and used a thresher to separate the rice ear. In modern times, there is a harvester that, after involving the rice ear, directly separates the rice ear from the rice stem, and a grain of rice ear becomes rice.

8. Drying and screening

The harvested rice needs to be dried. In the past, it was mostly dried in the front yard of the courtyard, which needed to be turned over from time to time to let the rice dry. Screening is to remove the grain and other impurities, using electric grain divider, windmill or manual shaking to divide the grain, using the wind to automatically screen out the full and heavy rice.