The ancient staple food is sharing its "growth diary"! How many members of the rice family do you know?

An ancient staple food with a long history

The rice on people's tables comes from paddy. After the paddy is husked, only brown rice is left. Only when the brown rice is processed and the bran layer is removed can refined rice be obtained. From planting to harvesting, each grain of rice has to go through a series of agricultural processes, including land preparation, seedling raising, transplanting, weeding, pest control, fertilization, irrigation and drainage, harvesting, drying and processing. Only by deeply understanding the production process of rice can we more deeply understand the poem: "When I hoe the rice at noon, my sweat drips into the soil. Who knows that every grain of rice on the plate is the result of hard work?"

Rice is one of the three major food crops in the world and one of the most important food crops in my country. Its planting area accounts for about 30% of the country's grain planting area, and its output accounts for about 50% of the country's grain output. In my country, more than 65% of the population relies on rice as their staple food. In addition, rice can also be used for brewing and industrial raw materials, and its rice husks and rice stalks can also be used as feed. In short, rice is a very valuable crop, and its whole body is a treasure.

China has the longest rice-growing history in the world, with a history of more than 4,700 years. The earliest rice cultivation can be traced back to Hunan, China, about 12,000 to 16,000 years BC. According to historical records, rice was already widely grown during the reign of Dayu, and gradually spread westward to India, and was introduced to southern Europe and other places in the Middle Ages.

China has a vast territory, rich resources and a wide variety of rice varieties. According to botanical classification, rice is divided into indica rice and japonica rice; according to the length of the growth period, it is divided into early rice, mid-season rice and late rice; according to the cultivation method, it is divided into rice and upland rice; according to the seed retention method, it is divided into conventional rice and hybrid rice. At present, the domestic conventional rice planting area is about 245 million mu, and the hybrid rice planting area is about 200 million mu. China's main rice producing areas are mainly distributed in the Yangtze River Basin, the Pearl River Basin and the Northeast region.

Rice Growth Diary

The life cycle of rice consists of two main stages: vegetative growth and reproductive growth. The growth period of rice can be as short as three to four months or as long as a year or even longer. The vegetative growth stage mainly includes the seedling stage and the tillering stage. The tillering stage refers to the period from the seedlings turning green after transplanting to the jointing. After the seedlings are transplanted, due to the damage to the root system, it takes 5-7 days for the root system to recover and sprout new roots. This recovery period is called the greening period.

Among them, the vegetative growth stage refers to the stage from germination of rice seeds to jointing of seedlings, which usually takes 90 days. This stage can be divided into the following four periods: ① Seedling stage, from germination of rice seeds to transplanting and transplanting, about 35 days. ② Transplanting stage, from the beginning of transplanting to the beginning of growth after planting, about 7-10 days. ③ Tillering stage, from the beginning of growth before jointing after transplanting, about 30 days. ④ Jointing stage, from the beginning of jointing to the beginning of heading, about 15 days.

The reproductive growth stage is the period from the beginning of rice heading to maturity, which is about 70 days and can be divided into the following four periods: ① Heading stage, from the beginning of heading to the beginning of heading, about 15 days. ② Heading stage, from the beginning of heading to the beginning of shelling and flowering, about 15 days. ③ Flowering and pollination stage, from the beginning of flowering to the beginning of grain filling, about 15-20 days. ④ Grain filling stage, from the beginning of grain filling to maturity and harvest, about 20 days.

The number of rice plantings is determined by the environment and the growth cycle of rice. Generally speaking, from north to south, rice is planted once a year, twice a year, and three times a year. Hainan's rice is a three-season crop, harvested in June, September, and December. This is because rice is a crop that likes high temperatures, high humidity, and short days. Hainan Island is located on the northern edge of the tropics and has a tropical monsoon climate with long summers and no winters. The average annual temperature is 22 to 27 degrees Celsius, so Hainan Island is also known as the "natural greenhouse."

Four types of rice with different ecological types

According to the differences in rice planting and growth ecological environments, rice can be divided into four ecological types: irrigated rice, rain-fed rice, upland rice and deepwater rice.

Irrigated rice grows in fields protected by dikes. If there are good irrigation conditions, it can ensure that one or more rice seasons a year are well irrigated. About 50% of rice cultivation belongs to this type, and the yield per mu is usually 200 to 600 kilograms.

Rain-fed rice also grows in fields protected by embankments, but due to the lack of irrigation and drainage facilities, irrigation and drainage cannot be effectively controlled.

Upland rice, also known as land rice, is a type of cultivated rice that is suitable for growing in vast dry land, sloping land and arid ecological environments. As a variant of rice, it is also known as drought-resistant and water-saving rice. Upland rice does not need a water layer throughout its life. It is usually moistened by rainwater after direct seeding in dry land or dry fields, or by appropriate supplementary irrigation on this basis. However, during the special critical growth period, upland rice must have irrigation conditions, otherwise it will have a great impact on yield. In the past 10 years, the aerated rice developed by the International Rice Research Institute has been developed from upland rice.

Deepwater rice refers to rice planted in low-lying areas that are prone to waterlogging and flooding. This rice variety can grow rapidly as the water depth increases, making the stems longer, with the top leaves above the water surface, and the plant length can reach 2 to 5 meters. Depending on the planting environment, deepwater rice can be divided into deepwater rice, floating rice and tidal rice. Deepwater rice varieties can adapt to deep water environments, and when floods come, most varieties can grow 2 to 3 centimeters a day. Floating rice varieties grow very fast when submerged.

Cultivating and growing unique types of "weird" rice

According to the cultivation and growth characteristics of rice, rice can be divided into artificial rice, lazy rice, giant rice and sea rice.

Artificial rice refers to hybrid rice, super hybrid rice and floating rice cultivated by scientific methods. In 1973, Yuan Longping successfully cultivated the world's first hybrid rice, for which he was hailed as the father of hybrid rice. The surprising thing about rice hybridization is that it is very easy to hybridize rice with other plants, even bamboo. Bamboo rice was produced through the hybridization of rice and bamboo. From the appearance, bamboo rice looks like bamboo, but it can produce granular fruits similar to rice.

The glutinous rice that regenerates every year is also called "lazy rice" because it does not need to be re-sown and transplanted every year. It only needs to be planted once and can be harvested for many years. The advantage of this "lazy rice" is that it solves the problem of wintering of the plants, and its growth cycle is about one month longer than that of conventional hybrid rice. In addition, "lazy rice" also has the characteristics of lodging resistance.

Giant rice is a tall rice plant with an upright body, long ears and many round and full grains. The plant height can reach 1.8 meters, or even up to 2.25 meters. The number of grains in a giant rice ear can reach 800, and the yield per mu can exceed 1,000 kilograms. In May 2022, the giant rice developed by Yuan Longping's team was officially planted in Ninghe District, Tianjin, and the trial was announced as a success in July 2022.

Sea rice does not grow in seawater or the sea, but grows in saline-alkali land such as beach mudflats. The salt-alkali tolerance of sea rice enables it to grow in saline-alkali land with a salt concentration of more than 0.3%, and the yield per mu can reach 300 kilograms.

The vigorous regenerated rice

In addition to the above-mentioned types of rice, there is another type of rice grown in a new mode, called regenerated rice. Regenerated rice is an innovative rice planting mode that can be harvested twice after planting once. After the mid-season rice is harvested, if the dormant buds that survive on the rice piles are used and given appropriate environmental conditions such as water, nutrients, temperature and light, the rice piles can regenerate a crop of rice. If the temperature is suitable, the germinated regenerated tillers can head in 20 to 30 days and mature in about two months.

Hubei is an important province for the cultivation of ratoon rice and a research center for the cultivation technology of ratoon rice, with an annual planting area of ​​about 3 million mu. The national planting area of ​​ratoon rice is about 15 million mu, and ratoon rice has become an important industry for increasing agricultural efficiency and farmers' income.

Produced by: Popular Science in China to Benefit Farmers

Scientific Advisor: Tang Zhong, Professor and Doctoral Supervisor, College of Agricultural Engineering, Jiangsu University

Co-ordinators: Liao Danfeng, Zheng Fengmao, Wang Changhai, Zhang Ruijie

Planning: Wu Yuetong

Editor: Lu Jingwen (internship)