(1) After slow seedling planting, the first irrigation with water and fertilizer is too early, and the nutrient growth is too strong, or the first irrigation with water and fertilizer is too late, and the nutrient growth is too weak. Second, the development of three-ear fruit, due to insufficient nutrition of plants, forms small fruits or beans and hard fruits.

(2) The density is too high and the fertility is insufficient.

(3) Without head-changing pruning, the fruits in the 4th and 5th ear were too small, which was mostly caused by the concentrated development of the fruits in the1~ 3rd layer, resulting in insufficient nutrition in the fruits in the 4th and 5th layers.

(4) When abnormal flowers are spotted, in order to prevent young fruits from cracking, the concentration of flowers is dropped too low or spotted too late, resulting in insufficient hormones and easy formation of hard fruits or small fruits.

(5) In some years or seasons, if the light is too weak and the temperature is low, it is easy to form stiff fruit or small fruit.