Propagation and Pest Control and cultivation techniques of Salix mandshurica

Propagation and Pest Control and cultivation techniques of Salix mandshurica

Silver bud willow (Salix leucopithecia), also known as silver willow, cotton willow, cat willow, silver willow, hairy dog, is a deciduous shrub of the family Salix. Salix mandshurica originated in the north of China, and has been introduced in many places at present. When winter comes, the leaves of silver willow will gradually fall off, revealing purplish red bracts. After the bracts are developed, they will reveal flower buds covered with silver-white supple fine hairs, which is the main ornamental part of silver willow. When the inflorescence unfolds, the shape of the flower spike is very similar to the cat's tail, so it is called "cat willow". Its English name Cat-tail willow also means cat's tail.

Silver bud willow mainly cuts its branches with flower buds for ornamental application, which is a traditional flower arrangement in winter in China. Its silver and white flower buds and purplish red bracts are just like a little girl dressed in red, beautiful and lovely; after taking off the bracts, the flower buds with supple and fine hairs show a more noble and elegant posture, and its flower buds are watched during the Spring Festival, coupled with the homophonic sound of silver willow and "silver two", representing auspiciousness and rolling wealth, so silver bud willow cutting is widely loved by people. The cutting can be raised in water, and the viewing period can be more than 2 months, and the dry insertion time is even longer. it can be used not only as a bottle, but also as a flower arrangement.

Since the 1990s, the market demand for silver bud willow pruning has increased sharply, and large-scale production has developed day by day. The flower buds of Salix mandshurica can also be dyed with various colors. In the Spring Festival flower markets across the country, silver white and silver bud willow branches dyed with red, yellow, green and purple are dazzling, attracting many people to buy. At present, there are a large number of commercial production in Shanghai, Yunnan, Jiangsu, Zhejiang, Sichuan and other places, and the products are also exported to Southeast Asia and even Europe and the United States.

I. Propagation technology

Fraxinus mandshurica is propagated by cutting with mature branches and is directly planted in the field. In general, the lower branches are cut off during pre-sale finishing in winter, trimmed into cuttings of about 20 cm long and 4-5 axillary buds, tied into small bundles, placed indoors and stored with river sand. In order to save the cuttings, according to Wang Lijun and other experiments, the cuttings can be cut into only 2 leaf buds, about 8 cm long. The specific cutting time varies from place to place. February is the appropriate time for cutting in the south, and the cutting in the open field in Beijing began in early April.

There are also a large number of cultivation and export of Salix mandshurica in Taiwan. their practice is to pick the cuttings after harvest at the end of December, pack and moisturize them, and store them under 4 ℃. This method is simple and convenient, and saves storage space. Two weeks after the Beginning of Spring is the suitable planting period, cut the cuttings into about 20 cm long, soak and disinfect them with carbendazim and other fungicides before cutting, and then dry in the shade before cutting.

II. Planting methods

The paddy field before selection is the best to reduce the occurrence of bacterial blight. Ploughing and preparing the land, applying basic fertilizer, setting up the bed, and then cutting.

The practices introduced by Ye Zengji in Shanghai are as follows: ploughing in the first and middle of February, applying basic fertilizer (applying organic fertilizer 2500 kg per mu), planting border width 1.7m, ditch width 0.3m, applying ammonium bicarbonate 15kg / mu, potassium sulfate or potassium chloride 10kg / mu, calcium superphosphate 25kg / mu, and covering the border with black plastic film. With 4 rows in each row, the stored cuttings with a length of about 20 cm were cut according to a distance of 20 cm to 25 cm, with about 6000 plants per mu. Sprouting about 2 weeks after cutting, if there are missing plants should be replanted immediately, so as not to affect the yield per unit area.

As the first year of cut flower cultivation, cutting culture single branch silver bud willow, the cut stem is thick and colorful, and the bud is full. In the second year, the multi-branched silver bud willow was cultivated by using the characteristics of early germination of seedling stubble, early defoliation in the lower part of branches and upward movement of flower bud nodes. After the flower branches are harvested, the plants are dug up and the new plants are cut back.

Third, wipe the buds and pick the heart

When cuttings sprout, 4-5 buds often occur at the same time, such as 2-year-old stubble Salix mandshurica sprouts more, each plant only retains 2-3 buds when sprouting. There is no need to pick the heart when only a single head of silver sprouts is produced. As some of the export products are multi-headed silver sprouts, it is necessary to use coring treatment to promote more than 3 branches in the upper part. When the length of the new shoot reaches 80 cm 100 cm, the top shoot 3 cm 5 cm should be removed, the time should be early May, and no later than May 20 at the latest. If the heart is picked too late, the branches will not reach the requirement of more than 60 cm. In order to ensure the commercial quality of Salix mandshurica, new shoots with strong growth potential must be selected for coring treatment, which is usually carried out on 2-year-old stubble plants. because 2-year-old plants branch earlier, their new shoots can reach a height of 1 meter 10-15 days earlier than 1-year-old plants. after coring, the branch length can finally reach more than 1 meter. In addition, because the lower part of the new shoot of the 2-year-old plant falls early, there is a longer section (about 50 cm) without flower bud at the base of the branch, so the quality of the single branch is not as good as that of the 1-year-old plant. As a multiple silver bud willow, the non-flower bud below the branch point does not affect the commodity quality, and the price is about twice as high as that of the single branch. In the one-year-old plant, some especially vigorous new shoots can also be selected and cultured into multiple silver sprouts after coring. In order to cultivate Salix mandshurica, more attention should be paid to the management of fertilizer and water.

The wide row planting method is adopted in Taiwan, with a row spacing of 30 × 150 cm. Usually two coring work is carried out after the cuttage survives. The purpose of the first coring is to increase the number of branches of Salix mandshurica in order to increase the yield per unit area, and the second is to increase the number of bifurcated branches of Salix mandshurica in order to increase the price of single branch. When the 14th leaf unfolds, it is the first time to pick the heart, and the new nutrient line Yinya willow is the most suitable for leaving 5-6 branches. When the plant grows to a height of about 100cm to 120cm, the second coring can turn a single branch into a bifurcated branch, and the best number of bifurcations is 2.

Salix mandshurica has a stronger ability to sprout in the rainy season, so it is necessary to wipe off the sprouting branches in time to ensure that the remaining branches have more nutrient supply. When erasing, you should pay attention to breaking off from the base, preferably when the sprouts are not lignified, and then you can break them off with your hands. Generally, the sprouting branches of Salix mandshurica can be Lignified in 3-5 days, so the degermination of Salix mandshurica should be carried out once in 3-5 days at most. [Jishan Huayao]

IV. Irrigation and fertilization

Silver sprouts like to be wet. If the continuous high temperature and drought exceeds 7 to 10 days from July to August, it must be irrigated in time. Irrigation should be carried out after 8 p.m., close the inlet after filling the border ditch and allow it to infiltrate on its own, and then open the ditch at dawn the next day to discharge stagnant water. The weather is getting cooler from September to October, and it should be irrigated if there is no rain for more than 10 days. Stop irrigation before defoliation to promote the maturity and fullness of branches. In the rainy season, we should pay great attention to drainage to meet the requirement of "rain stops the field to dry".

Silver bud willow likes fertilizer, in addition to applying sufficient base fertilizer, it also needs to be fertilized for 2 or 3 times during the growing period. If the base fertilizer is insufficient, the fertilizer should be applied once when the branch is about 10 cm long in mid-late April, and urea can be applied to 10-15 kg per mu. The period from May to June is the most exuberant period of branch growth, and the compound fertilizer dominated by nitrogen can be applied once in the middle and last ten days of May, applying 2530 kg per mu. The period from August to September is the period of flower bud differentiation, and the balanced compound fertilizer of nitrogen, phosphorus and potassium can be applied once in August. The compound fertilizer of N-P2O5-K2O=15-15-15 is 30kg / mu. In addition, 0.2% potassium dihydrogen phosphate plus 0.5% urea was used for 2 times of extra-root topdressing in September, which significantly promoted the expansion and coloring of buds.

In addition, ploughing and weeding is also an important daily management work. Often loosening the topsoil can reduce water evaporation, increase soil temperature, promote the decomposition of nutrients in the soil, and create good conditions for the absorption and growth of root nutrients. In the seedling stage, it is necessary to carry out intertillage as soon as possible, with the growth of the plant, gradually stop the intertillage, and give priority to weeding.

V. Prevention and control of major diseases and insect pests

The main diseases harmful to Salix mandshurica are Rhizoctonia solani and black spot. The incidence of blight was mainly in the seedling stage, which caused cuttings rot and shoot wilt. Attention should be paid to cuttings disinfection and cuttings should be soaked in 800 / 1000 times of carbendazim or topiramate before cutting. In addition, we should pay attention to avoid continuous cropping and continuous cropping, and the former cropping rice field is the best. Black spot harms leaves, stems and buds. At the beginning of the disease, the leaves produce small brown spots, and when the disease spots are serious, the leaves are withered, and the flowers or branches can be harmed in the later stage to form black spots, which can be controlled by antiseptic, carbendazide, polysulfide mixture, methyl topiramate and so on. The main pests harmful to silver bud willow are red spider, shell insect, diamondback moth, armyworm, night moth, inchworm, aphid, tea wing bug, leaf borer, leaf beetle and so on.