Nitrogen is the most important nutrient for the growth and fruiting of chestnut trees. Chestnut branches contain 0.6% nitrogen, leaves 2.3% nitrogen, roots 0.6% nitrogen, male flowers 2. 16% nitrogen and fruits 0.6% nitrogen. The absorption of nitrogen started from root activity in early spring, and gradually increased with germination, leaf spreading, flowering, new shoot growth and fruit expansion, and still rose before harvest.

After harvest, it began to decline and stopped absorbing during dormancy. The most nitrogen is consumed in the spring growth period. Therefore, supplementary application of nitrogen fertilizer in spring is beneficial to the growth of new shoots, making leaves thicker and dark green, improving photosynthetic efficiency, promoting flower bud differentiation and fruit growth and development, and has a great impact on yield. However, too much nitrogen in the later stage will cause the branches to grow white, which will affect the enrichment of branches and the differentiation of flower buds. Sometimes when the branches grow twice, they will produce secondary flowers and fruits, but the fruits are immature, which will affect the yield in the next year. Therefore, the focus of nitrogen supply is the early stage.