Because walnut is a deciduous tree, it grows rapidly and its skin is dark brown. Fleshy root system, water and humidity resistance, drought resistance and insect resistance.
Walnut is light-loving, cold-resistant, drought-resistant, disease-resistant, adaptable to a variety of soil growth, water-loving and fertilizer-loving, and has low requirements for water and fertilizer. It is not suitable for pruning after defoliation and before germination, which may easily lead to bleeding. Walnut is an angiosperm.
In the international market, walnuts, almonds, cashews and hazelnuts rank as the four largest dried fruits in the world. Its footprints are almost all over the world, mainly in America, Europe and many parts of Asia. Its output is in addition to the United States, that is, China. Walnut is called "Hercules food", "nutritious nut" and "educational fruit" abroad. In China, it enjoys the reputation of "Long live the child", "longevity fruit" and "treasure for nurturing people".
Its outstanding brain-nourishing effect and rich nutritional value are praised by more and more people. Walnut belongs to the dried fruit of deciduous trees in Juglandaceae. Walnut has a long history of cultivation in China. In the Natural History written by Zhang Hua in the 3rd century BC, it was recorded that "when Zhang Qian went to the Western Regions, he had to return walnut seeds". Walnut's hometown is Iran in the west of Asia, and it was introduced to China when Korea and Zhang Qian went to the Western Regions. Today, walnuts are distributed all over China. For a long time, the working people in China have carefully cultivated many new varieties of high-quality walnuts by using the common and wild walnut resources in China. If classified by origin, there are Chencang walnut and Yangping walnut; According to maturity classification, there are summer walnuts and autumn walnuts; According to the smoothness of the shell, there are light walnuts and hemp walnuts; According to the thickness of the shell, there are thin-shell walnuts and thick-shell walnuts. There are many excellent varieties of walnuts in China, such as "Shimen Walnut" in Hebei, which is characterized by fine grains, thin skin and sweet taste. The kernel yield is about 50% and the oil yield is as high as 75%, so it has the reputation of "Shimen Walnut is the treasure of the world".
The paper walnut in Kuqa, Xinjiang, is called "Kekeyi" by Uighurs, which means the shell is thin and the oil content reaches 75%. This variety bears fruit quickly, and the masses describe it as "one-year-old, two-year-old and three-year-old walnuts hanging in baskets". Walnuts in Fenyang, Xiaoyi and other places in Shanxi are famous for their thin skin, full kernel and tender meat. The walnut skin in Qinling area of Shaanxi Province is as thin as an egg shell, commonly known as "egg-skinned walnut". The best variety is "Mian Walnut", with thin skin and thick flesh. Hold two walnuts in your hand, and with a little force, the walnut skin will break. In addition, the small walnuts produced in Hangzhou are also very popular with southerners.
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