Detailed Explanation of Key Techniques for Winter Frost Protection of Fruit Trees

In winter, fruit trees are prone to frost damage, so protecting them from frost is very important. Below is a detailed explanation of the key techniques for frost protection of fruit trees, for everyone's reference.

1. Whitewashing tree trunks

Whitewashing tree trunks can protect the trunks and reduce frost damage. To prepare the whitewash, use 30 kg of quicklime, 2-3 kg of sulfur powder, 0.5 kg each of agricultural salt and flour, a small amount of vegetable oil, and add 100 kg of water to mix. Or directly use Wolingdun whitewash for protection.

2. Mounding soil and wrapping

Mound soil around the trunk to a height of about 40 cm, forming a steamed-bun shape. The soil should be taken from a distance; it is best to combine this with applying organic fertilizers such as pond sludge and tidal mud. If soil is taken from within the tree basin, then although the main trunk may be kept warm, the roots within the tree basin are often left bare or the fine roots are too close to the surface soil, which often worsens frost damage. Generally, mounding soil around the time of Major Snow and removing the soil around the time of Awakening of Insects is suitable.

3. Covering fruit trees

Use straw curtains or plastic film to directly cover the tree canopy to improve the frost resistance of fruit trees. For young fruit tree seedlings, use a full-cover method to raise the ground temperature and increase the survival rate of young fruit tree seedlings.

4. Fertilizing for cold protection

Drought weather often worsens frost damage. Each place can adapt to local conditions and irrigate once with “winter water” to reduce frost damage, restore tree vigor, and enhance resistance. Combine irrigation with applying winter fertilizer; winter fertilizer should be mainly organic fertilizer, with an increased proportion of phosphorus and potassium.

The amount of fertilizer applied should be supplemented according to the amount of fruit produced. For heavily frost-damaged trees, the fertilization period can be appropriately delayed.

In addition, each place should effectively carry out winter orchard cleanup work to prevent damage from diseases and pests and protect healthy leaves that have not been frost-damaged so they can overwinter. After the beginning of spring, promptly apply additional fertilizer to fruit trees, mainly nitrogen fertilizer, using more human waste and urine, applying frequently and lightly, to promote new branches and new leaves, promote fruit tree growth, and restore tree vigor.

5. Heating and smoking

Use local materials and collect weeds, rice husks, wood shavings, fallen leaves, etc., making 4-6 piles per mu, cover with wet grass or thin mud, and light them before a windless clear night to produce smoke, suppress radiation inversion, and prevent frost. However, this measure must ensure fire safety.

6. Biogas slurry for frost protection

Experiments have shown that applying biogas slurry can strengthen tree vigor and has the effect of preventing frost damage. The method is: filter the biogas slurry with gauze at the concentration of the original liquid; if the concentration is too high, appropriately dilute it with water, spray it with a sprayer, and evenly spray all branches and leaves. It is required to spray once every 10-15 days after fruit harvest, for three consecutive sprays.

7. Removing accumulated snow

Use tree branches to gently tap the branches of fruit trees so that the snow attached to the fruit trees falls to the ground, reducing frost damage to leaves and branches from accumulated snow.

8. Pruning green wood after freezing

For orange trees that have already suffered frost damage, promptly prune the green wood, that is: cut off the more severely frozen autumn shoots and late autumn shoots, keeping the cut surface with green color two centimeters below the frozen branch. For lightly frozen branches, if the leaves have already dried up, promptly remove the dead leaves to avoid water loss, prevent worsening of frost damage, and restore tree vigor as quickly as possible.

9. Thinning flowers and fruit

For fruit trees with relatively severe frost damage, all flower buds should be removed at the early flowering stage in spring to ensure vigorous tree vigor; for lightly frozen fruit trees, do a good job of thinning flowers and fruit, thinning heavily and leaving few, and at the same time, apply more fruit fertilizer to improve orchard production efficiency