Soybean belongs to Papilionaceae, soybean genus, alias soybean. Many ancient books in China once called soybean glutinous rice, and it was recorded in the Book of Songs that "there was glutinous rice in the Central Plains, and Shu Ren adopted it"; Du Yu commented on the word "glutinous rice, soybean also" in the Western Jin Dynasty; After Qin and Han Dynasties, the word "bean" was used instead of "dragon". Soybean is native to China, and it is estimated that China has been planting soybeans for more than 4,700 years. The history of soybean cultivation in Europe and America is very short, and/kloc-0 was introduced from China in the late 9th century. In 1930s, soybean was planted all over the world.

Characteristics of soybean

The optimum growth temperature of soybean is 20-25℃. When the temperature is higher than 20℃, soybean will blossom and pod, and the plant has poor cold tolerance. When the temperature is lower than 14℃, the plants will not bloom and pod will slow down. Soybean has a high demand for water. When watering, it should be wet and dry alternately. The soil water content is about 70%-80%, but it is not allowed to accumulate water in the soil, otherwise it will lead to rotten roots.

The amount of fertilizer absorbed by soybean before flowering is less than 15% of the total absorption, while the flowering and pod-setting period accounts for more than 80% of the total absorption. Soybean likes warm weather, and the seeds begin to germinate at 12. The optimum temperature is 20, the growth is 25 and the flowering is 23.