Seedling raising technique of Picea koraiensis

Purple fruit spruce (PiceapurpureaMast), commonly known as iron pine, is a tall coniferous tree, which likes wet, cold and dry climate, and the young forest has strong shade tolerance. Mainly distributed in Qinghai, Sichuan and Gansu. It is widely distributed in the shady slopes, semi-shady slopes and river valleys of the Bailong River forest region, Taohe forest region and Daxia River forest region at an altitude of 2800-3600m above sea level in Gannan, forming a unique forest landscape in high mountains. It plays an important role in conserving water sources and preventing soil erosion. At the same time, it is one of the excellent native tree species, and it is an important tree species for forest regeneration and barren mountain afforestation in the high, cold and humid zone of Gannan Plateau. According to the practice of raising seedlings of purple fruit spruce in Gannan forest region, the seedling raising techniques of purple fruit spruce are summarized as follows.

1 nursery site selection

The nursery land should be selected at the altitude of 24003000m, the land is low, open and flat, sunny and smooth in drainage and irrigation, the soil tillage layer should be above 30cm, the content of organic matter is higher, and the soil quality should be neutral and acidic.

2. Make a bed by preparing the ground.

To prepare the nursery for sowing in the second year, a deep ploughing was carried out after the autumn of that year, and the depth was 30~35cm. Ploughing the soil layer to pick up stones and other sundries, fully make the soil loose and ventilated. In the spring of the second year, after the soil was thawed, the soil moisture was irrigated according to the soil moisture. When the soil moisture was suitable for ploughing, a shallow ploughing of the nursery was carried out at the depth of 20~25cm. Combined with shallow ploughing and applying rotten farm manure or oil residue as base fertilizer, the dosage is: farm manure 2000~2500kg/667m2, oil residue 250kg/667m2. Then make a seedling bed, the seedling bed for the east-west direction, can fully accept the light, increase the ground temperature. Bed height 15~20cm, width 100cm, trail width 30~40cm. The bed should be flat and the drainage ditch is smooth to prevent seedling blight caused by stagnant water.

3 soil disinfection

Soil disinfection should be carried out in newly sown and transplanted plantations. In autumn ploughing, 50% phoxim of 5~8kg/667m2 or 4% furan powder of 10~15kg/667m2 were mixed with appropriate amount of soil and sprinkled evenly in the soil to eliminate underground pests. At the same time, 7-10 days before spring sowing and seedling transplanting, 3911 (potassium mixed with phosphorus) was sprinkled in combination with shallow tillage, and the ratio of 3911 to sand was 3, 7, 311, 5kg and 667m2; in addition, 75% methyl topiramate or 80% Zinc was used and mixed with the right amount of soil. Sprinkle it in topsoil for disinfection, or pour 30% ferrous sulfate of 2~5kg/667m2 evenly on the seedbed.

4 sowing

4.1 seed treatment

The seeds were treated 3 days before sowing, selected by wind several times, then soaked the seeds in cold water for 2 hours, removed the floating gravure and sundries, then soaked the seeds in 0.5% 0.1% copper sulfate solution for 2 hours, washed the seeds with clean water or soaked the seeds with 0.5% potassium permanganate for 2 hours, sealed 30min after being removed, and then rinsed and dried with clean water for budding treatment.

4.2. Seed germination

The sterilized seeds were soaked in clear water for 24 hours and then stacked to accelerate germination. The germination temperature should be kept at 18-20 ℃. In order to prevent water evaporation and seed mildew after germination for more than 24 hours, rinse properly with 18-20 ℃ water for 2 times. When the crack rate of the seed reaches 30%, the seed can be sown.

4.3 seeding rate

Under the condition of normal germination rate of 70%-90%, the sowing rate of purple fruit spruce seedlings is 20~30kg/667m2. According to the seedling raising experience of purple fruit spruce in the alpine area of Gannan, the fresh seeds collected from the mother forest of purple fruit spruce come out well, and the suitable sowing rate is 20~25kg/667m2, while the fresh seeds collected from other seed collection bases or fine stands are better, and the sowing rate is 25kg/667m2.

4.4 sowing seeds at the right time

The best sowing time is that after the soil is thawed in spring, the soil temperature below the seedbed is kept above 5 ℃ and stabilized at more than 3 days. Generally, sowing can be carried out when the surface temperature is above 6.5℃. Through the experiment, the best sowing time of purple fruit spruce is from late May to early June in Gannan region.

4.5 sowing method

The use of sowing, sowing 8.0cm, amplitude 10cm, uniform sowing. After sowing, it was covered with humus, and the thickness was controlled at 0.7~0.8cm. After covering the soil, it is compacted with rolling wood, and then covered with bamboo curtain in time.

5 nursery stock cultivation

5.1 cultivation of sowing seedlings

5.1.1 timely removal of mulch according to the seedling experiment for many years, in Gannan area (elevation 2950m), after sowing for about 1520 days, the seedlings began to be unearthed, and by early July, the seedlings were completely unearthed. When more than 60% of the seeds are unearthed, remove the mulch in time. This work should be carried out in cloudy or sunny evenings, and be careful not to pick up the seedlings.

5.1.2 sunshade in Gannan area, the surface temperature can reach 45 ℃ in summer. In order to prevent seedling burns, a sunshade should be built. Shed height 40~50cm, slightly wider, longer than the seedbed 10~20cm, sunny side, the shed should be wider than the seedbed 10cm or so to prevent direct sunlight on the bed surface. In case of continuous overcast and rainy days, when the soil moisture is saturated, open the shed properly to promote water evaporation. The covering is suitable for sunshade net, and the transmittance is 40% and 50%.

5.1.3 when smoke and frost prevention is used, the smoke will last for 2 hours after El. When spraying water and frost, spray according to the amount of 3~4mm water every hour until 1 hour after sunrise.

5.1.4 fertilization the fast-growing period of purple fruit spruce seedlings in Gannan area is from late July to mid-August, about one month, at this time combined with irrigation to apply diamine phosphate compound fertilizer, the dosage is 10kg/667m2, and then evenly sprayed on the bed after melting. Spraying clear water immediately after fertilization, flushing away the fertilizer on the seedlings, during the fast-growing period, the average height growth net value of seedlings can reach 0.8cm, and the accumulation of dry matter accounts for more than half of the total accumulation of the whole year, so during this period, special attention should be paid to strengthening the management of fertilizer and paddy fields and increasing the growth of seedlings as much as possible. From late August to the end of October, the seedlings grew slowly, entered the Lignification growth stage and capped one after another. in order to increase the Lignification degree of the seedlings and enhance the overwintering ability, plant ash fertilizer (potash fertilizer) was applied once before the seedlings began to cap in late September to promote Lignification and ensure the seedlings to survive the winter safely.

5.1.5 after the seedlings came out, the seedlings were carried out for the first time with reasonable density, and the seedlings with overdense growth, unsound development and affected by diseases and insect pests were pulled out, so that the seedlings were evenly distributed. To ensure that the number of plants per unit area is 20%-30% higher than the planned seedling yield, the principle is that the density between rows is sparse, the inter-row is inferior, the number of seedlings is 2-3 times, and the final seedling is 900-1000 plants / m2. The seedlings were combined with weeding, and the seedlings were replenished in the areas with too sparse seedlings, and the roots were watered in time after the seedlings were replenished.

5.1.6 Irrigation should always keep the seedbed moist. In the bed soil whitening with spray pot watering, each watering should be thoroughly, continuous rainy days, should be timely covered with plastic sheet rain, do a good job of drainage. At the end of October, after completely capping, the seedlings should be irrigated with frozen water for once in order to survive the winter.

5.1.7 weeding and loosening the soil in mid-July, weeding should be done in time. Weeding and loosening soil should be carried out together, and weeding should grasp the principle of "removing early, removing small, except". Weeding 3-4 times from June to August and twice in other months.

5.1.8 overwintering management Gannan plateau winter comes early, and the climate is cold, after all the seedlings are capped, the overwintering measures should be taken in time. Cover the seedbed with a layer of newspaper and then a layer of mixed soil mixed with sawdust, which is characterized by light weight, good air permeability and thermal insulation, and is easy to withdraw the following year. Grass curtain can also be used to cover, the effect is also very good, after covering the shade canopy can not be removed to prevent direct sunlight in winter when the bed surface reheating phenomenon.

5.2 cultivation of transplanted seedlings

5.2.1 after transplanting season and graded sowing seedlings for 3 years, they should be transplanted in time. After the soil thawed in the early spring of the fourth year, before the seedling terminal bud germinated and the tree sap flowed, it was suitable for Gannan area from late April to early May. The seedlings should be graded and high-quality strong seedlings should be selected for transplanting.

5.2.2 when transplanting, the transplanting board was used to control the row spacing of seedlings, and the seedlings of the same level were transplanted together with a transplanting density of 350,400 plants / m2. Transplant should be done along with the planting, planting, compaction, to prevent the root, root or burying leaves, burying seedlings, after planting fixed root water.

5.2.3 Management of transplanting seedlings first cover the shade shed after transplanting, and remove the shade shed after the seedlings grow, so that the seedlings can fully receive sunlight, and the transplanted seedlings will no longer be covered during overwintering. Sprinkle nitramine 2 days before and after the middle of June, the dosage is 10~15kg/667m2, if there is no rain after fertilization, be sure to sprinkle water with a spray pot to wash away the fertilizer left on the seedlings so as not to burn the seedlings.

(6) Disease and pest control

6.1 Disease prevention

Purple spruce 1-year-old 2-year-old seedlings are easy to be infected with blight, generally from the end of June to the beginning of July, after the seedlings are unearthed for 3 years, 0.67% Bordeaux solution or 0.5% 0.1% ferrous sulfate solution is sprayed regularly once a week (spraying foliar solution with clean water after 30min), 2 times in a row, and then sprayed every 10 days and 15 days. If the disease is found, the diseased plant should be removed immediately and burned centrally, and then sprayed once, continuously for 2-3 weeks, until the disease disappears. Purple fruit spruce is also susceptible to spruce rust, which can be sprayed with 0.5% diphacinone sodium solution.

6.2 Pest control

6.2.1 stem and leaf pests are mainly pine aphids, leaf wasps, etc., which can be sprayed with 0.06%-0.1% omethoate.

6.2.1 Underground pests are mainly beetles, ground tigers, golden bell worms, nematodes and other pests, which should be controlled during the larval stage. If harmful phenomena are found, the roots can be irrigated with 0.125% phoxim immediately, or 10% methyl isathion 5~10g/m2 mixed with fine soil can be used to open ditches, and then watered. 40% omethoate solution of 0.125% to 0.167% was sprayed during the adult stage.