Walnut, also known as walnut and peach, is a kind of walnut plant. Together with almonds, cashews and hazelnuts, it is known as the world-famous "four dried fruits". Walnut kernel is rich in nutrition, with protein 15 ~ 20g per 100g, more fat and carbohydrate 10g, and contains many trace elements and minerals such as calcium, phosphorus and iron, as well as many vitamins such as carotene and riboflavin. It's good for the human body. It is one of the nut foods deeply loved by ordinary people. Walnut shells are hard and need to be broken open to eat.

According to China Statistical Yearbook in 2008, the national walnut cultivation area is1.667 million hm? About 400 million plants. According to the statistics of the Afforestation Department of the State Forestry Administration, there are 800,000 hm of walnuts cultivated in Yunnan Province. , 333,000 hm in Shanxi Province? , 30.2hm in Shaanxi Province? , 200,000 hm in Hebei Province? .

According to the statistics of China Forestry Yearbook in 2008, the total output of walnuts in China in 2007 was 499,000 t, accounting for 29.35% of the world's total output, including 9 1 10,000 t in Yunnan, 64,000 t in Shaanxi, 53,000 t in Shanxi and 47,000 t in Hebei. At present, China's walnut production investment is low, the variety improvement degree is low, and the cultivation management technology level is limited. Compared with the United States, the yield per unit area is low, the national average yield per plant is about 1.5kg, and the unit area is less than 20kg/㎡.