Seedling raising techniques of Pinus tabulaeformis in North China

Seedling raising techniques of Pinus tabulaeformis in North China

1. Land selection and preparation

Pinus tabulaeformis likes the land with fertile, loose and deep soil layer, and requires good drainage and convenient irrigation. When sowing and raising seedlings, choose sandy loam or loam, and require pH value to be neutral or weakly acidic [Jishan Huayao]. In the northern region, seedlings in mountainous areas can generally choose shady or semi-sunny slopes with flat terrain and small slope, and have a higher content of humus. Because there are root fungi in the root of Pinus tabulaeformis seedlings, continuous cropping can be used in raising seedlings, and the effect of continuous cropping is very good. In addition, seedlings can be raised in conifers, bauhinia and other stubble, but the effect is not good in elm, Robinia pseudoacacia and the former crops are corn, potatoes, melons and vegetables. After selecting the land, ploughing the plot in the autumn of the year before sowing requires deep ploughing, and the best ploughing depth is 30~50cm.

2 seed treatment

In order to improve the germination rate of seeds and reduce the occurrence of diseases and insect pests, it is necessary to do disinfection, seed soaking and germination treatment before sowing Pinus tabulaeformis seeds. In disinfection, generally choose 0.5% formalin solution or 0.1% potassium permanganate solution to soak the seeds for 30-60 min, and rinse the seeds with clean water after disinfection. The main purpose of seed soaking is to eliminate the effect of waxy layer on the seed surface of Pinus tabulaeformis. It can be soaked in warm water about 35 ℃ for 24 h. After soaking the seeds, the seeds were taken out and placed in the environment of 25: 30 ℃ to accelerate germination. When the seeds were cracked, the seeds could be sown.

3 sowing and raising seedlings

In the northern region, generally sowing in April, it is necessary to clean up the sundries in the nursery before sowing, and then make the bed, which is generally made into a seedbed with a width of about 1m, while the length can be determined according to the topography, and a 30cm walkway is needed between the seedbed belts, which is convenient for weeding, loosening soil and other operations. In addition, in order to reduce the occurrence of soil diseases and insect pests, the pesticide (about 375mol / L ferrous sulfate and 45 kg/hm 2 / 3% trichlorfon powder) can be evenly sprinkled into the soil, and then ploughed, or mixed with base fertilizer and applied to the seedling field. When sowing, the best base fertilizer is rotten farm organic fertilizer, and the amount of fertilizer is 30000 kg/hm 2. In addition, it can also apply appropriate amount of urea 225 kg/hm 2, phosphate fertilizer 375 kg/hm 2, potassium fertilizer 225 kg/hm 2.

4Seedling stage management

After sowing and emergence of Pinus tabulaeformis seeds, the growth time of Pinus tabulaeformis seedlings is longer, generally need to grow for about 3 years, in the seedling growth stage, if not managed properly, the growth rate will be slowed down. Therefore, in the growth stage of Pinus tabulaeformis seedlings, we must do a good job of management.

4.1 Protection before emergence

Because of the fragrance of Pinus tabulaeformis seeds, it is easy to attract some insects, birds or mice to eat. Protective measures should be taken before the seedlings are ready after seed germination, especially the prevention and control of birds and mice, which can be protected by artificial care, placing rodenticide and so on until the seedlings come out.

4.2 Water and fertilizer management

Pinus tabulaeformis seeds are different from other tree seeds which are easy to germinate, and sufficient water is needed after sowing, so it is necessary to sprinkle the seedling field once every morning and evening after sowing, but we should pay attention to not spraying too much water and no stagnant water. The soil can be moist after each sprinkling. After the seedlings come out, they can be irrigated according to the soil moisture. With regard to fertilization, generally speaking, fertilization is no longer carried out in the same year because sufficient base fertilizer has been applied before sowing; in the second year, fertilizer can be applied according to the growth of the seedlings, if the seedlings show obvious malnutrition phenomena such as slender stems and yellowing needles, or when the seedlings are in the fast-growing period, they need to be topdressing in time, mainly nitrogen fertilizer, and appropriate matching of phosphate fertilizer and potash fertilizer.

4.3 weeding and loosening the soil

After the seedlings come out, if the surface sprinkles too much water or more rainfall, the soil will harden. Because the root system of Pinus tabulaeformis seedlings is underdeveloped and the growth is weak, it is difficult to absorb enough nutrients after soil hardening. It is necessary to loosen the soil in time to promote the growth of Pinus tabulaeformis seedlings. At the same time, when there is more rainfall or watering, it will also accelerate the growth rate of weeds, the growth of weeds will not only compete for soil nutrients, but also occupy the growth space, affecting the growth of Pinus tabulaeformis seedlings. Therefore, when weeds are found, weeds should be weeded in time.

4.4 overwintering protection of seedlings

It is cold in winter in the northern region, and Pinus tabulaeformis seedlings have weak cold resistance due to underdeveloped root system and weak growth. in order to ensure the survival rate of seedlings in winter, scientific and reasonable cold prevention measures need to be taken. Before overwintering, the effect of freezing injury can be reduced by winter irrigation on the surface of the soil. In addition, in very cold areas, the seedlings can be buried in the soil, or choose wheat straw to cover the seedling bed, or use plastic film to cover the seedling bed.

(5) Disease and pest control

The main diseases of Pinus tabulaeformis seedlings are blight, rot, powdery mildew and so on, and the main pests are Dendrolimus punctatus, pine sheath borer and so on.

5.1 Diseases

5.1.1 Fusarium wilt

5.1.1.1 damage characteristics: shortly after Pinus tabulaeformis was unearthed, brown stripes could be seen. With the passage of time, the stripes gradually expanded, the roots of seedlings became reddish brown, the root cortex began to rot, and then withered and died. Pinus tabulaeformis seedlings will die.

5.1.1.2 Prevention and control methods: first of all, select the nursery to avoid raising seedlings in the plant growing areas that are susceptible to the disease, and at the same time, when fertilizing cultivated land, you can sprinkle 70% dimethopone 4% 6 g Aigao 3, or irrigate the seedling site with 2%-3% ferrous sulfate solution, the dosage is 9 Lago 3. Secondly, when sowing, it is necessary to fertilize reasonably, and when applying farm organic fertilizer, it must be fully mature. After emergence, the plants at the early stage of the disease can be sprayed with 72.2% of Purek 400 times, or 20% methyl rifampicin EC 1,200 times, or 75% chlorothalonil wettable powder 600x, or 50% wettable chlorpromazil 80000g 1000 times, or 1 ∶ 1 ∶ 100 Bordeaux solution.

5.1.2 Rot disease

5.1.2.1 damage characteristics: it mainly damaged the central trunk and the lower cortex of the main branch. The disease is reddish brown at first, slightly raised, watery, posterior cortical rot, often flow out of yellow-brown juice, wet rot, with the smell of wine lees, the disease spot is round or oval, the edge is not clear, sometimes showing a deep and shallow wheel shape.

5.1.2.2 Control methods: strengthen cultivation management, cut branches in time, cut down diseased plants and burn them, and select local tree species with strong stress resistance. In addition, you can also shave off the diseased skin and apply fungicides for 1 or 2 times, which can be treated with 40% thiophanate, acetonitrile, stone sulfur mixture, 843 rehabilitation agent, rotting agent and so on.

5.1.3 powdery mildew

5.1.3.1 harm characteristics: mainly damage to new shoots and young leaves, after the new shoots were damaged, the internodes shortened, the leaf margin rolled up, the quality was hard and brittle, the injured part was covered with a layer of white powder, and the whole shoot withered in the later stage.

5.1.3.2 Control methods: remove pathogens; strengthen cultivation management; chemical control mainly include methyl topiramate, carbendazim, benate, formearsine and so on.

5.2 insect pests

5.2.1 Dendrolimus tabulaeformis generally occurs in the Spring Festival, the initial occurrence period is in late March, the overwintering larvae begin to do harm to the tree crown, the requirement of living environment is getting higher and higher, and the beautiful garden environment has become the main factor for people to consider. The growing material and cultural demand has stimulated the development of leisure tourism and health preservation industry, while the development of leisure tourism and health preservation industry is inseparable from the support of the garden industry, and the development of the garden industry has led to the recovery of the seedling market.

3 advantages of Pinus elliottii in landscaping, afforestation, wind prevention and sand fixation

3.1 landscaping and afforestation

In the face of the good forestry development situation, with the help of the national forest promotion policy, with the rising status of native tree species in landscaping, Pinus elliottii, as a unique native tree species in China, will have great potential in the seedling market in the future. Because of its beautiful tree appearance, peculiar bark and high ornamental value, it is very favored in landscaping. Pinus elliottii can be planted in many places because of its resistance to barren and drought.

3.2 preventing wind and fixing sand and accelerating dust reduction

White bark pine has many branches, dense needles, well-developed root system, and has a good effect on preventing wind and fixing sand and accelerating dust reduction. If a shelterbelt is built in the wind-damaged area, the wind speed within the protective area can be reduced by about 30%, and the total leaf area of the forest can reach 75 times of its occupied area. A shaped white pine has about 6.6 million needles, coupled with some hairy structures on the leaves, which greatly enhance the adsorption of dust.