Detailed Explanation of Pinus bungeana Planting Techniques and Management Methods
Pinus bungeana (lacebark pine) is an evergreen tree of the genus Pinus in the family Pinaceae, reaching up to 30 m in height and 2 m in diameter at breast height. It is a light-demanding species, and young trees tolerate partial shade; its cold tolerance is inferior to that of Pinus tabuliformis, but its drought tolerance, moisture tolerance and adaptability to soil are all stronger than those of Pinus tabuliformis. It can adapt to dry-cold climates of -30°C and soils with a pH of 7.5 to 8; it can grow in limestone areas, but cannot grow in poorly drained or waterlogged places, and it has strong resistance to pollution from sulfur dioxide and soot and dust. It is deep-rooted and long-lived. The branches of young trees are naturally distributed, dense and uniform, so no pruning or shaping is needed to form a beautiful crown. It grows relatively slowly; a one-year-old seedling is only 3 cm to 5 cm tall, and after 10 years it reaches about 1 m in height.
Growth Habits of Pinus bungeana
It grows in areas at an altitude of 500-1800 m. It is a light-loving tree species, tolerant of barren soil and relatively dry-cold climates; it grows well on cool temperate, deep, fertile and moist calcareous soils and loess soils.
Pinus bungeana is a tree species endemic to China, produced in Shanxi (Luliang Mountains, Zhongtiao Mountains, Taihang Mountains), western Henan, the Qinling Mountains in Shaanxi, southern Gansu and Maijishan in Tianshui, Guanwu Mountain in Jiangyou, northern Sichuan, and western Hubei, among other places. It is also cultivated in Suzhou, Hangzhou, Hengyang and other places.
Propagation Techniques for Pinus bungeana
1. Seed propagation: Pinus bungeana is generally propagated mostly by sowing. The nursery site should be chosen as well-drained, flat land with deep sandy loam soil. Sowing immediately after the ground thaws in early spring can reduce pine seedling damping-off disease. Because it fears waterlogging, high-bed sowing should be used; before sowing, water the bed thoroughly, use about 1 kg of seeds per 10 sq m, which can produce 1000 to 2000 seedlings. After broadcast sowing, cover with soil 1 to 1.5 cm deep and cover with plastic film, which can increase the germination rate. After the seedlings emerge completely, gradually increase the ventilation time until the film is completely removed. After sowing, the seedlings emerge with the seed shell attached, which falls off on its own after about 20 days; during this period, bird damage must be prevented. During the seedling stage, a shade frame should be erected to prevent sunscald, and before winter the soil should be mounded up for cold protection. Young seedlings have long main roots and few lateral roots, so when transplanting, care should be taken to damage the lateral roots as little as possible, otherwise they are prone to withering and dying.
2. Grafting propagation: If softwood grafting is used for propagation, the softwood shoots of Pinus bungeana should be grafted onto older Pinus tabuliformis rootstock. When softwood shoots of Pinus bungeana are grafted onto 3- to 4-year-old Pinus tabuliformis rootstock, the survival rate generally reaches 85% to 95%, with strong compatibility and fast growth. The scion should be selected from vigorous new shoots, with a thickness of 0.5 cm being preferable. When bare-root transplanting two-year-old seedlings, the root system must be protected to avoid drying and damage; they should be dug and planted immediately, and thereafter turned and bedded every few years to promote fibrous roots, which helps the establishment and survival of planting. Generally, large seedlings over 10 years old are used for landscaping. Transplanting is best in early winter during dormancy and in early spring when the ground thaws; when using large seedlings, they must be transplanted with a soil ball. To plant large seedlings with a diameter at breast height of less than 12 cm, a soil ball 120 cm high and 150 cm in diameter must be dug, wrapped with straw rope to secure the soil, and during transport the soil ball must be prevented from breaking; after planting, stakes must be erected and ties used for support.
Field Management Techniques for Pinus bungeana
1. Site selection and land preparation: Choose the nursery site well. Pinus bungeana seedlings fear waterlogging, so the nursery site should be selected as flat land with irrigation and drainage conditions. Heavy clay soil, saline-alkali soil and low-lying waterlogged land are not suitable as nursery sites. Prepare the land finely: the nursery land should be deeply plowed, leveled and raked fine, and sufficient base fertilizer applied, such as decomposed pen manure or compost. Calcium superphosphate can also be mixed with cake fertilizer or farmyard manure, etc., for better results. Before land preparation, scatter 10 kg of ferrous sulfate powder per mu and plow it into the soil for sterilization and disinfection. After the land is prepared, make beds running north-south, with bed ridges 25 cm high and beds 1 m wide, ready for sowing.
2. Seed germination: Pinus bungeana seeds should be soaked and disinfected with Bordeaux mixture. Before sowing, soak the seeds in warm water (50°C to 60°C) to promote germination or stratify them with sand to promote germination; when the number of split seeds reaches 50% of the total number of seeds, they can be sown. In this way, the seedlings emerge strong and uniform, and generally they can emerge and sprout in 15 to 20 days.
3. Sowing and seedling cultivation: Sowing is generally best 10 to 15 days after the soil thaws (late March to early April). Before sowing, water the bed surface thoroughly, sow 1 to 1.5 kg per 10 sq m, which can produce about 1500 seedlings, using wide-row drilling or broadcast sowing. After sowing, cover with fine sandy soil 1 to 1.5 cm deep; use 125 g of prometryn plus 250 g of 25% wettable chloronitrofen per mu mixed with 25 kg of water, and spray it on the seedbed with a sprayer for weed control. Finally, build a small arch shed over the bed surface to increase temperature and retain moisture and raise the emergence rate; no watering is needed before emergence. Because mice like to eat pine seeds, before building the arch shed and covering the film, scatter some rat poison on the bed surface.
4. Seedling stage management: After the seedlings emerge completely, gradually increase the ventilation time of the seedbed, and strengthen their resistance through hardening off. Pinus bungeana loves light, but the seedlings are relatively shade-tolerant; after removing the film, shade netting should be covered immediately to prevent the harm of high-temperature sunscald and damping-off disease.
Fertilizer and Water Management Techniques for Pinus bungeana
In long droughts without rain or during high summer temperatures, water in time. Weeding should follow the principles of early weeding, small weeding and complete weeding; weed between plants by hand pulling to prevent damage to the seedlings. After weeding broadcast-sown seedlings, cover with soil appropriately to prevent cracks. For drilled seedlings, combine weeding with loosening the soil, and carry out thinning and replanting at the same time. Then drain promptly.
For Pinus bungeana seedlings, base fertilizer should be the mainstay, with topdressing as a supplement. From mid-May to the end of July, during the peak growth period, carry out topdressing 2 to 3 times, mainly with nitrogen fertilizer: apply decomposed human excrement or pig manure at 3 dan per mu, mixed with about 20 dan of water; decomposed cake fertilizer at 5 to 15 kg per mu made into about 15 dan of cake fertilizer water; and apply about 4 kg of urea per mu. In the later growth stage, stop applying nitrogen fertilizer and increase the application of phosphorus and potassium fertilizers to promote lignification of the seedlings; a 0.3% to 0.5% potassium dihydrogen phosphate solution can also be sprayed on the leaves.
Pinus bungeana seedlings grow slowly and are suitable for dense planting. If large-sized seedlings are to be further cultivated, 2 to 3 more transplantings are needed before final planting. Two-year-old seedlings can be transplanted with soil in early spring before the terminal buds have sprouted, with a spacing of 20 to 60 cm; do not damage the terminal buds, water twice in succession after planting, and water again after 6 to 7 days. For 4- to 5-year-old seedlings, a second transplanting with a soil ball can be carried out, with a spacing of 60 to 120 cm. After survival, keep the soil around the tree roots loose, apply 100 to 120 kg of decomposed organic fertilizer per plant, water thoroughly after covering with soil, and thereafter strengthen management to promote growth and cultivate strong seedlings.
Pest and Disease Control Techniques for Pinus bungeana
Pest and disease control: after sowing, watch for damage to seedlings by bean seed fly larvae; the base fertilizer applied must be fully decomposed and crushed. The pine aphid harms the young branches and needles of seedlings, easily causing sooty mold, resulting in weakened tree vigor and even death. Control method: in the early stage of damage, spray 50% phoxim emulsion, with each kg mixed with 2000 kg of water.