Detailed Explanation of Post-Harvest Management Techniques for Chestnut Trees

Before fruit harvest, chestnut trees begin flower bud differentiation; after fruit harvest, the tree's nutrients are extremely depleted. Whether autumn and winter management can be strengthened in time affects the quality of flower bud differentiation and has a great impact on the next year's yield.

1. Rational fertilization, provide enough to “eat.” Generally, every 100 kg of mature chestnuts requires the consumption of 4.5-5 kg of pure nitrogen and potassium each, and 1.5-2 kg of phosphorus. After fruit harvest, the tree's “vitality” is greatly damaged, so fertilizer should be applied promptly to help it quickly recover tree vigor, increase the accumulation of nutrients, and improve the chestnut tree's cold resistance for overwintering. The fertilizer applied should be mainly organic fertilizer. Generally, for 8-10 year old trees, apply 50-60 kg of barnyard manure, 0.5 kg of urea, and 1 kg of phosphate fertilizer per tree in trenches; for trees over 10 years old, increase or decrease the amount of fertilizer according to the fruit load.

2. Irrigation and drought resistance, provide enough to “drink.” The root system of chestnut trees is widely distributed horizontally and has weak vertical distribution ability. After fruit harvest, the tree loses a great deal of water, and because autumn and winter droughts are generally severe, chestnut trees are easily affected by drought. Therefore, after fruit harvest, chestnut orchards with the conditions should promptly irrigate thoroughly once to replenish the tree's water, and afterward timely irrigation is still needed if drought occurs.

3. Mounding soil around the base, provide enough to “wear.” Mounding soil around the trunk can ensure root growth of the tree and enhance its cold resistance. In mid-to-late November, depending on the size of each tree, use 2-4 baskets of decomposed farmyard manure spread flat under the canopy with the trunk as the center, then cover with a layer of fine soil. When temperatures rise in the spring of the following year, dig it open again to facilitate aeration and root growth, and it can also reduce weeds.

4. Pest and disease control, carry out “health care.” After fruit harvest, promptly clean the orchard, prune dead branches and branches seriously affected by pests and diseases, and remove fallen diseased and pest-damaged branches and leaves on the ground, burning them in a centralized manner or burying them cleanly. In autumn, pesticides should be applied in a timely manner against the main pests harming chestnut trees. Corresponding pesticides may be selected respectively from double-strength Bordeaux mixture, 40% omethoate emulsifiable concentrate 1500-2000 times solution, 2.5% deltamethrin emulsifiable oil 8000 times solution, etc.

5. Rational pruning, surgical “beautification.” In autumn, chestnut tree sap is still flowing and the temperature is relatively high. Pruning at this time not only allows wounds to heal quickly, but can also avoid the sprouting of water sprouts near the wounds. For chestnut trees in the early fruiting stage, only thin out dense branches and improperly positioned water sprouts; for trees in the full fruiting stage, mainly thin and remove, combining thinning with renewal, maintain the tree shape, and coordinate the relationship between vegetative growth and reproductive growth; for aging trees, it is advisable to systematically retract branch groups, renew and rejuvenate them, and prolong their fruiting life.