When did double-cropping rice first appear, and in which dynasty? A detailed explanation of sowing and harvest times

Double-cropping rice is a rice farming system in which two crops of rice are planted and harvested in the same paddy field within one year. According to differences in cultivation methods, it can be further divided into double-cropping continuous rice, intercropped rice and mixed-cropped rice, and it has a long history of cultivation in China. So, when did double-cropping rice first appear, and in which dynasty? What are its sowing and harvest times?

1. When did double-cropping rice first appear, and in which dynasty?

It is earliest found in records in the “Classic of Mountains and Seas” from the 3rd century BC. It is generally believed that the “two-crop rice” and “second-crop rice” often mentioned in ancient texts include ratoon rice, mixed-cropped rice, intercropped rice and continuous-cropping rice, reflecting the diversity of China's rice farming systems. The emergence of double-cropping rice played a very important role in making full use of natural resources and labor resources and increasing grain output.

2. When are the sowing and harvest times for double-cropping rice?

For double-cropping rice, transplanting of early rice seedlings begins in mid-to-late May, and the early rice is harvested in mid-to-late July. Then the paddy field is immediately plowed and late rice seedlings are transplanted, which must be finished before the Start of Autumn on the lunar calendar, and the late rice is harvested in November, with harvesting completed before frost. Single-cropping rice is transplanted from mid-to-late June to early July each year, and harvesting begins in mid-to-late October. The yield per mu of single-cropping rice is higher than one season of double-cropping rice, but the total amount is much lower than that of double-cropping rice.

3. Double-cropping rice cultivation methods

1. Land preparation

Before planting rice, the soil in the paddy field must first be turned over to make it soft. This process is divided into three stages: coarse plowing, fine plowing and leveling. In the past, animal power and plows were used, mainly water buffaloes, to prepare the land and plow the fields, but today machinery is mostly used for land preparation.

2. Seedling raising

Farmers first raise seedlings in a certain field, which is often called a seedling field. After sowing the rice seeds, farmers usually spread a layer of rice husk ash on the soil; in modern times, specialized seedling centers mostly use seedling boxes to grow rice seedlings. Good rice seedlings are the key to successful rice farming. When the seedlings grow to about eight centimeters tall, transplanting can begin.

3. Transplanting

The seedlings are carefully transplanted into the paddy field at orderly intervals. Traditional transplanting methods use seedling ropes, seedling markers or transplanting wheels to make marks in the paddy field. When transplanting by hand, a seedling separator is worn on the left thumb to help the farmer separate the seedlings and insert them into the soil. The weather during transplanting is very important, as heavy rain can damage the seedlings. In modern times, rice transplanters are often used, but in paddy fields with large fluctuations in terrain and non-square shapes, manual transplanting is still needed. Seedlings generally run in a north-south direction. There is also the more convenient method of throwing seedlings.

4. Weeding and pest control

While the seedlings are growing, they must be cared for at all times, and weeds must be pulled. Sometimes pesticides are also needed to kill pests (such as golden apple snails).

5. Fertilization

When the seedlings shoot up and grow their first rice stem node, this is called the tillering stage. During this period, fertilization is often needed to let the rice seedlings grow robustly and to promote the fullness and quantity of the grain after heading later.

6. Irrigation and drainage

Paddy rice depends relatively heavily on this procedure. For upland rice, the field is dry, and the irrigation and drainage process is different, but generally after transplanting, when the young panicle forms, and during the heading and flowering stage, water irrigation must be strengthened.

7. Harvest

When the rice ears hang down and are golden and full, harvesting can begin. In the past, farmers cut them bundle by bundle with sickles, then tied them up and used a threshing machine to separate the rice ears. In modern times, there are harvesters that pull in the rice ears and directly separate the rice ears from the rice stems, so that the grains of rice ears become rice grain.

8. Drying and screening

The harvested rice grain needs to be dried. In the past, it was mostly dried in the front courtyard of a three-section compound, and it had to be turned frequently to let the rice grain dry. Screening removes impurities such as shriveled grain. Electric grain separators, winnowers or manual shaking are used to separate the grain, using wind power to automatically screen out the full and heavy rice grains.