Fast-growing poplars are planted in my hometown. Please understand the friends to provide some breeding techniques.

Choosing suitable afforestation sites for poplar growth is the basic condition to realize fast growth and high yield of poplar. Poplar is a fast-growing tree species among deciduous broad-leaved trees, and it grows best in alluvial soil with deep, loose, fertile, moist and well-drained soil. Poplar afforestation sites are mainly in plain areas and mountain valleys, and the afforestation sites shall meet the following conditions:

1, the soil layer is deep, and the effective soil layer thickness is greater than 1.0m (sandy land).

2. The soil texture is very light. Populus (such as Populus euramericana 107, Populus euramericana 108, etc.). ) grows best in medium loam and heavy loam, followed by sandy loam and sandy soil; Poplar species (such as Populus tomentosa) can grow in heavy soil.

3. The groundwater level is suitable. The suitable groundwater level for poplar growth should be about 1.5m, and the growth period should be lower than 1m and not less than 2.5-3m.

4. The soil has high nutrient content. Minimum requirements: organic matter content is greater than 0.4% and nitrogen content is greater than 0.03%.

5. The soil contains no or little salt. The soil salt content should be lower than 0.65438 0%.

Second, the specifications of land preparation.

After the drainage and irrigation ditch system is repaired, the afforestation land will be arranged into holes with a diameter of 0.8- 1.0m and a depth of 0.8-1m.

Third, seedling selection

1, select improved varieties. Choose different poplar varieties according to different cultivation objectives. (1) plywood. Plywood needs large-diameter wood, with straight and complete dry form, no scars, moderate wood hardness and good rotary cutting and drying bonding performance. The varieties suitable for plywood cultivation are mainly Populus nigra, such as Populus euramericana 107, 108, Populus pekinensis and Populus Langfang. (2) Pulp wood. Pulp wood requires poplar varieties to grow fast, the wood color is light, the wood density is high, the cellulose content is high, the fiber length (above 0.9 mm), the fiber length-width ratio is greater than 35, the wall-cavity ratio is less than 1, and the impurity content is low. Poplar varieties suitable for cultivating pulp wood are Zhonghe 1, Lin Zhong 46 and triploid Populus tomentosa. (3) Furniture materials. The trunk is required to be straight and complete, with few scars, high wood density, meticulous structure, low heartwood content, high mechanical strength and hardness, easy to dry, swell and shrink, easy to process and good adhesive performance. The main varieties are Populus tomentosa, Populus shenzhou and 74 1 poplar.

2. Choose strong seedlings. The experiment proved that selecting 2-year-old seedlings with roots 1 year or 2-year-old seedlings with roots higher than 4.5 meters and 3.5 centimeters for afforestation in DBH not only has short seedling stage and strong ability to resist natural disasters, but also has fast growth, early maturity and high timber yield. The requirements of strong seedlings are developed and complete roots, strong seedlings, highly lignified branches, full terminal buds, no mechanical damage and no pests and diseases.

Fourth, afforestation density.

Reasonable afforestation density should be determined according to the characteristics of poplar varieties, site conditions of afforestation sites, cultivation objectives, rotation period and other factors. Afforestation land with good site conditions. Varieties with fast growth and large crown have low density and poor site conditions when cultivating large diameter timber. Varieties with straight stem and narrow crown can cultivate forests with short rotation period and higher density. Generally, the planting density of short-period pulp forest is 2× 3m, 3× 3m and 3× 4m, and the planting density of plywood and furniture is 5× 6m, 6× 6m and 4× 8m to cultivate large-diameter timber.

Verb (abbreviation of verb) planting technology

1, seedling treatment. In all aspects of seedling raising, seedling transportation and planting, it is necessary to prevent seedlings from losing water. In the seedling field, we should follow the principle of watering before seedling, pay attention to protect the root system in the shipment of seedlings, make the root system complete, fresh and moist, and try to grow, transport and plant with it. Seedlings that can't be planted in time should be soaked in clear water and taken as they are planted. Cut off all side branches and parts before planting.

2. Planting time. Poplar can be planted in spring, late autumn and early winter, after defoliation and before germination.

3. Planting method. Depending on the soil conditions, it is appropriate to plant about 60 cm in dry and loose soil, but not deep planting in cohesive soil and low-lying land. During afforestation, it is required to plant in big holes, strengthen the body, fill the soil in layers and step on it, so that the roots of seedlings can stretch and be closely connected with the soil, water them immediately after planting, strengthen the seedlings after seepage, and raise the soil to seal the holes.

Six, tending management

1, timely irrigation. Poplar is a fast-growing tree species, which requires high water content. Therefore, timely irrigation can not only improve the survival rate of afforestation, but also promote the growth of poplar. In addition to immediately watering the newly built young forest, in the dry season from April to June, the woodland should be irrigated in time to ensure the vigorous growth of the forest. Irrigation should also be carried out in autumn drought, and winter irrigation of Populus deltoides and other varieties can improve the drought and cold resistance of trees. Irrigation times and irrigation amount depend on weather and soil conditions. Generally, it is watered four times in a rainy year. First, green water, before germination in late March; The second is to promote water and expand branches and leaves from May to June every year; The third is to water in summer drought; 4. 1 1 month is filled with frozen water. Water 30-50 cubic meters per mu each time, and intertillage and moisturize after watering.

2. Rational fertilization. (1) base fertilizer: Before afforestation, apply 5- 10 kg of soil miscellaneous fertilizer and about 0.5 kg of calcium superphosphate to each plant, and then mix them and apply them to the root system planting depth in the dug tree hole. (2) Topdressing: 200-230g urea is applied to each plant in May of the next year, and 330-400g urea is applied to each plant in May of the third year. It can be applied later and less in the year of afforestation, and it can be applied more appropriately with the growth of forest age, and pay attention to the coordination of nitrogen, phosphorus and potassium, and combine topdressing with watering.

3, loosen the soil and weed. Weeding should be done at least twice a year before trees are closed, and crop management can be combined with intercropping. Weeding times can be reduced appropriately after canopy closure. During the intercropping of agriculture and forestry, it is not specially used to loosen the soil for forest land. After the intercropping stops, loosen the soil 1-2 times a year at least to loosen the soil and prevent the soil from hardening.

4. plums. Timely pruning can improve the quality of trunk and cultivate high-quality wood with perfect trunk shape. When planting trees, trim all the side branches of the seedlings. For young trees 1-3 years after afforestation, competitive branches are removed, auxiliary branches are retained, and sprouting strips are cut off at the base of trunk to cultivate upright and robust trunk. The pruning intensity should keep the crown height ratio above 3∶4. Plywood should have no scab. When the base trunk of the first round of lateral branches reaches 10- 12 cm, pruning is carried out to remove the first round of lateral branches and cultivate a good product without knots. Pruning should be carried out after the trees have fallen leaves in autumn, and the incision should be smooth, so as not to tear the branches.

For the trees after four years, the weak branches under the crown should be pruned step by step to keep the following ratio between the crown length and the tree height: the tree height is greater than 10 m, and the ratio of crown height is 2 ∶ 3; The height of the tree is more than 20 meters, and the ratio of crown height is1∶ 2; The height of the tree is more than 25 meters, and the ratio of crown height is 1∶3.

5, the implementation of agroforestry, farming instead of caressing. Agroforestry intercropping before closing hillsides not only improves the land utilization rate, but also promotes the growth of trees through crop management measures such as loosening soil, weeding and watering. Intercropping crops should be short, shade-tolerant, with less water consumption and fertilizer, such as soybeans and peanuts, or melons, vegetables, medicinal materials and wheat. The distance between crops and trees should be greater than 1 m, so as not to destroy the roots of trees or compete with trees for water and land.