Cutting Seedling technique of Populus tomentosa in North China

Populus tomentosa is a southern evergreen tree species, which belongs to Populus tomentosa. For many years, it is deeply loved by people because of its low plant, compact, dense leaves, beautiful shape, evergreen and many other advantages, and is widely used in hedge and modeling design in landscaping. It is one of the most widely used tree species in northern landscaping, but it has been difficult to raise seedlings in the north due to the influence of climate and other factors. The greening seedlings in the north can only be transported over a long distance from the south, which not only increases the cost, but also the survival rate of seedlings is low. In this regard, we conscientiously sum up the experiences and lessons in the cuttage of Populus tomentosa, changing the winter cuttage to summer cuttage, the soil substrate to stone substrate, and the old branch to tender branch, and this natural condition is the protection condition. After many experiments, we have summed up a set of cuttage seedling raising technology of Populus tomentosa in the northern region, and large-scale popularization has been successful, not only the survival rate is more than 85%, but also easy to operate and grow seedlings quickly. It put an end to the history of difficulty in raising seedlings of boxwood in the north. Last year, we used this technique to cut and raise 400000 seedlings. The specific operation methods and technical points are as follows:

I. requirements of cutting bed

1. The cutting bed should be selected on the land with good ventilation and drainage, the bed should be built according to the border surface 1-1.2 meters, the operation belt 0.5-0.6 meters, the bed should be surrounded by standing bricks, the bed surface should be turned deeply and leveled, in order to fill the substrate, and the operation belt should be hardened with bricks.

two。 Matrix: stone to stone powder with better water retention and permeability should be selected, and clean fine river sand can also be replaced. The thickness of the matrix is generally 4cm to 5cm, and the lower layer should add 2 cm thick coarse sand.

3. Sunshade: use the solar greenhouse to remove the film and cover the sunshade net with a shading of 65%. The non-solar greenhouse can also use bamboo poles or steel frames to build scaffolding, which is generally 20-30 meters long from north to south and 6-8 meters wide from east to west, and the scaffolding should be firm in preparation for covering film in winter.

4. Micro-spraying: because of cutting with leaves in the growing season, micro-spraying is the main measure of cooling and humidification, the sprinkler should be evenly distributed according to the diameter of the spray, and the border surface should not leave a dead corner, it is best to choose a full-automatic intermittent spraying device, which can also be controlled manually if the condition is poor.

II. Insertion requirements

1. Cutting time: it can be cut from mid-May to early August, and it is best before and after the peak of new shoot growth.

two。 Mother plant and cuttings: cuttings are the internal factors affecting the survival of cuttings. according to experience, it is better to choose the mother plant that is younger (1-5 years old) with strong growth and free of diseases and insect pests. Cuttings choose one-and-a-half-lignified clumps or single branches and biennial rosettes, generally without more than three-year-old branches.

3. Management of cuttings: cutting should be carried out before 10:00 and after 4 p.m., and cut with cuttings in a cool place after harvest to reduce water loss. Above 4 cm above the base of the cuttings, branches and leaves should be removed, 2-3 leafy branchlets should be left in the upper part, 5-6 cm cutting shoots should be left in the upper part, and a certain number of leaves should be left in the cuttings to facilitate rooting. Because Populus tomentosa belongs to the rooting type of callus, the wound caused by debranching at the base is also beneficial to rooting. After the branches are treated, they are bundled with 30-50 pieces (base should be complete) and dipped into a container containing 2-3 cm of water for use.

Third, cuttage

1. The base of cutting should be sprayed with water, not dry cutting.

two。 Before insertion with hormone treatment, generally with 500 mg / kg of oral acetic acid quickly dipped in the base of the branch.

3. The row spacing is generally 4 cm × 4 cm, or 5 cm × 5 cm. It can also be inserted 2 cm × 2 cm, and then transplanted after rooting. The cutting depth should be 4-5 cm, and the matrix around the branches should be compacted by hand after cutting.

IV. Plug-in management

1. Humidity control: humidity is the key factor affecting cutting survival, including substrate humidity and air humidity, general substrate water content should be kept at 15% 25%, too much water, decreased ventilation will cause branch mildew and rot, air relative humidity should not be less than 70%. Therefore, the time of micro-spraying should be determined according to the specific cutting time, weather conditions and rooting conditions, and the spraying time should be appropriately prolonged in the high temperature period. In the morning, evening and rainy days, spray less or not as appropriate, spray more in the rooting period within 1 month after cutting, spray less after rooting, and drain water in time in case of heavy rain.

two。 Pest control: because the cuttage is in the high temperature season, the humidity is high, and the branches are susceptible to disease, it is necessary to spray carbendazim or chlorothalonil every other week, and use medicine in time if there are leaf-eating insects.

3. If the cuttings are not transplanted in the same year after survival, foliar fertilizer should be sprayed every 15 days, generally spraying 0.3% 0.5% imported urea or compound fertilizer.

4. If transplanting in the same year, the shading net and water control should be gradually removed 2 months after planting, so that the seedlings can gradually adapt to the external environment after planting.