What technical measures are there for post-disaster production recovery of forest specialty seedlings and flower nurseries?

I. Field-grown seedlings

1. Shake off ice and snow in good time. On the premise of ensuring personal safety, promptly clear the snow from the plants to avoid freeze damage; never shake it off by force, so as to avoid fallen leaves and broken branches, and protect the tree body as much as possible.

2. Clear ditches and drain water. Promptly clear ditches and drain water around the nursery land to reduce the soil moisture content of the nursery land and prevent freeze damage and waterlogging from occurring at the same time. For seedlings that have suffered severe freeze damage, even more attention should be paid to soil moisture management after they sprout, because both excessive waterlogging and excessive drought are unfavorable to the recovery of plant growth.

3. Support and tie up. Bent or lodged seedlings should be promptly straightened or replanted, and if necessary, tied with supports. For large grafted seedlings whose graft union is above ground, the graft union should be sealed with plastic for insulation to prevent and reduce freeze damage to the seedlings.

4. Wound care. The torn branches should be promptly put back to their original growing position, fixed by binding fine palm rope over the crack, then evenly coated with a protective agent on the crack (white lacquer used in woodworking can be chosen as the protective agent), and then wrapped with plastic film about 2 cm wide. This measure must be implemented promptly, the torn bark layers must fit closely together, and the binding should be loosened only after healing is firm; for torn branches and trunks, their branches and leaves should be appropriately reduced to decrease consumption.

5. Pruning and trimming. Pruning and trimming is one of the commonly used remedial measures after freeze damage, and should be handled according to the degree of damage to the plant: for plants with relatively light freeze damage, strictly apply "better shallow than deep" light pruning to clean up the plants, so as to facilitate bud sprouting; for those with relatively severe damage, deep pruning or heavy pruning should be carried out, promptly cutting off the frozen parts to promote the sprouting of new shoots.

6. Earthing up and fertilizing. When there is no standing water in the ditches of the nursery land, earth up promptly to increase soil temperature; the height of earthing up varies from 3 to 5 cm above the ground according to differences in seedling species and seedling age, and it should be promptly removed when the soil temperature is higher than 10°C. For precious seedlings, rice straw, leaves, sawdust and the like can be used to cover the seedbed to increase insulation. For plants with relatively light freeze damage, 0.2% to 0.5% urea can be used for 2 to 3 foliar topdressings; after thawing in early spring, apply sufficient spring fertilizer early to restore growth vigor. For plants with severe freeze damage, it is advisable to apply thin fertilizer frequently, with special attention to the fertilization period, aiming to promote spring and summer shoots while controlling autumn shoots.

7. Pest and disease control. Frozen seedlings have relatively weak growth vigor and are often prone to pests and diseases. Thiophanate-methyl and chlorothalonil 800-fold solution can be sprayed for disinfection, and Bordeaux mixture can be used to brush the bark and wounds to prevent the occurrence of diseases. Earth up promptly and maintain trunk moisture so that they recover naturally. In addition, frequent monitoring is also required, and once pests or diseases are found, corresponding measures should be taken immediately for control.

II. Protected cultivation seedlings and flowers

1. Reinforce the shed structure. For damaged flower greenhouses, promptly repair and reinforce the greenhouse frame and shed film, immediately clear snow, reduce pressure on the shed body, increase the light transmittance of the film, and raise the shed temperature.

2. Drainage and freeze prevention. Promptly clear snow from inside the shed and from the ditches around it, clear ditches and drain water, so as to prevent melted snow water from seeping into the shed through the soil at the shed feet.

3. Reasonable topdressing. Spray quick-acting fertilizer on frozen plants to promote plant recovery and enhance the plants' cold resistance and freeze resistance. For flower seedlings such as Chinese rose, large-flowered cymbidium, and clivia, different fertilizers should be applied according to different varieties.

4. Increase temperature inside the shed. Adopt temporary heating measures such as light bulbs, heating, and temporary combustible materials to reasonably regulate the temperature inside the shed; when burning for heating, prevent gas damage. To increase temperature and prevent freezing, a small shed can be built inside the large shed, arched with fine bamboo and covered with double-layer film.

5. Prune branches and prevent diseases. Severely frozen branches and leaves should be promptly cut off and cleared out of the shed to avoid mildew-induced diseases. Promptly spray protective agents and insecticides and fungicides, and also combine topdressing with strengthened management to restore growth as soon as possible. After the plants resume growth, spray a broad-spectrum agent such as thiophanate-methyl once on the leaf surface to prevent and control the occurrence of diseases.