The lowest temperature of seedling germination is 10 ~ 12℃, and the optimum temperature is 28 ~ 32℃. The average daily temperature at tillering stage is above 20℃, and the optimum temperature for ear differentiation is around 30℃. Low temperature prolonged the differentiation of branches and glumes. The optimum heading temperature is 25 ~ 35℃. The optimum flowering temperature is about 30℃, lower than 20℃ or higher than 40℃, and pollination is seriously affected.
Extended data
cultivation techniques
Rice planting techniques, including paddy field and transplanting, were invented in China. Legend has it that Shennong taught people how to grow rice. In addition to traditional manual farming methods, there are also highly mechanized farming methods. But still don't lose the following steps:
Carry out soil preparation
Before planting rice, the paddy soil must be ploughed to make it soft. This process is divided into three stages: rough tillage, fine tillage and leveling. In the past, people used animals and plows, mainly buffaloes, to prepare and plow the land, but now, people use machines to prepare the land.
grow seedlings
Farmers first cultivate seedlings in a field, which is usually called a paddy field. After sowing rice seeds, most farmers will sprinkle a layer of rice husk ash on the soil. In modern times, special seedling-raising centers use seedling-raising boxes to make rice seedlings grow. Good rice seedlings are the key to the success of rice cultivation. When the seedlings grow to about eight centimeters, they can be transplanted.
Transplanted rice seedlings
Insert the seedlings carefully in the rice field, and the space is neat and orderly. The traditional transplanting method will mark the rice field with seedling rope, seedling label or transplanting wheel. When transplanting rice by hand, you will wear a seedling separator on your left thumb to help farmers divide seedlings and insert soil.
The climate of transplanting rice seedlings is very important, such as heavy rain will damage the seedlings. There are many rice transplanters used in modern times, but in paddy fields with large fluctuations and non-square shapes, manual rice transplanting is still needed. Generally, seedlings will show a north-south trend. It is also more convenient to throw seedlings.
nutrition
The harvested rice grains are called rice and have shells. When milling rice, the husk is often removed together with the rice bran layer, and sometimes a thin layer of glucose and talcum powder is added to make the rice grains shiny.
Rice with only the husk removed during rice milling is called brown rice, which is rich in starch and contains about 8% protein and a small amount of fat, including thiamine, nicotinic acid, riboflavin, iron and calcium. Rice without husk and rice bran is called polished rice or white rice, and its nutritional value is greatly reduced.
use
The way of eating rice is mostly cooking. In the East, the Middle East and many other regions, rice can be served with various soups, side dishes and main teas. By-products of rice milling include rice bran, ground rice bran powder and starch extracted from rice bran, all of which are used as feed. The oil obtained from rice bran processing can be used as food and industry. Broken rice is used to make wine, extract alcohol, and make starch and rice noodles.
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