How to Grow Taxus wallichiana var. mairei? A Detailed Guide to Seed Sowing and Seedling Techniques
Taxus wallichiana var. mairei grows slowly and has a long lifespan, making it an excellent shade-tolerant tree species. Nowadays many growers have begun to choose to plant Taxus wallichiana var. mairei. Below, the editor will explain the seed sowing and seedling techniques for Taxus wallichiana var. mairei.
1 Selection of Nursery Site and Land Preparation
For the nursery site of Taxus wallichiana var. mairei, a plot with sufficient sunlight, convenient drainage and irrigation, and deep, loose, fertile soil should be selected as the seedbed. The soil should be deep-plowed and broken up, then made into beds with a width of 1.5 m (net bed surface width about 1.2 m), a path width of 0.3 m, and a bed height of 20 cm. Before land preparation, apply 1,500 kg of decomposed organic fertilizer and 50 kg of quick-dissolving high-quality compound fertilizer per mu, and mix in 5-8 kg of 3% carbofuran granules to control underground pests. After turning and mixing the fertilizer into the soil, level the bed surface. 10 days before sowing, use 50 mL of 40% formalin per square meter, add 10-12 kg of water, evenly sprinkle on the soil, and cover with plastic film. Remove the film 3-4 days before sowing, then sow.
2 Seed Propagation
2.1 Seed Collection
For local Taxus wallichiana var. mairei seeds, after mid-October, harvest in batches when the outer seed coat of the fruit turns dark red. If too early, the seeds are immature and the germination rate is low; if too late, they easily fall off, and furthermore birds and rodents will feed on them.
2.2 Special Treatment of Seeds
Because the outer seed coat of Taxus wallichiana var. mairei seeds is bony and hard and covered with a waxy layer, and the seed coat is wrapped by an aril, normally it generally requires 2-3 years and post-ripening dormancy before germination, and the germination rate is very low. In order to shorten the germination time and improve the germination rate, special treatment should be carried out.
Place the newly collected seeds in a bamboo basket, stir and rub with a wooden mallet, or mix the seeds with sand and put them in a cloth bag to rub. The rubbing should not be too heavy; use even force to avoid damaging the hilum and reducing the germination rate; after washing away the aril with water, repeat the rubbing in the same way until the outer seed coat cracks and about 30% of the seed kernel is exposed; then rinse away the outer seed coat and sand particles with running water, and never sun-dry. After the seeds are treated, carry out sand storage and germination promotion. Store semi-moist river sand and seeds at a ratio of 3:1 in a cool, ventilated indoor room or cellar, turn the pile once every 1-2 months, and check for pests and diseases and prevent rodent damage.
2.3 Sowing Method
After the seeds have been stored in semi-moist sand stratification for several months, sieve them out and wash them clean the following spring, float off the shriveled grains, soak and disinfect with 0.5 g/L potassium permanganate solution for 10 min, then rinse clean with clear water, and sow after drying. Broadcasting is mostly used for sowing. Evenly scatter the seeds on the seedbed filled with yellow subsoil. When sowing, mix seed with pesticides such as dichlorvos, zinc phoxim, mancozeb, and metalaxyl, along with calcium phosphate fertilizer, and broadcast. This not only allows the seeds to be sown with fertilizer, but also
controls pests and diseases. The sowing rate is generally 25 kg/hm2. After sowing, lightly rake the surface soil with a fine-toothed rake to cover the seeds, or cover the seeds with yellow subsoil, with a soil cover thickness of 1-2 cm. After covering with soil, cover with rice straw or plastic film.
2.4 Seedling Stage Management
2.4.1 Shading at the Seedling Stage In early to mid-April, when the temperature has gradually stabilized and begun to rise, promptly remove the film and cover with a shade net (shading rate 70% in the early stage and 50% in the later stage), covering tightly and securely to strictly prevent wind damage, rodent damage, and bird damage. Until the end of the fast-growing period, in mid-to-late September, choose a cloudy or rainy day to remove the shade net, so that the autumn shoots of Taxus wallichiana var. mairei grow rapidly and tenderly. The timing of film removal is crucial; if too early, the new shoots of the seedlings will be scorched yellow, and if too late, it will affect the growth of side branches and hardening of the seedlings.
2.4.2 Pest and Disease Control After the seedlings emerge, they are susceptible to infection by pathogens, causing root rot and damping-off disease. Control focuses on "prevention." After the seedlings emerge, spray every 7 days with 50% thiophanate wettable powder at 1.25 g/L solution or half-strength Bordeaux mixture, evenly spraying the seedling stems, leaf undersides, and leaf surfaces. Soil pests and diseases should also be prevented in a timely manner; drench the roots with dexon and phoxim, and add carbofuran once in the middle stage.
2.4.3 Thinning and Transplanting If sowing is uneven, causing seedlings to be too dense or too sparse, transplanting must be carried out from late May to mid-June, thinning where dense and filling in where sparse. The transplanting method is to choose a cloudy or rainy day or after rain for transplanting, rinse the root ball with clear water, and transplant.
2.4.4 Cultivation, Weeding, Fertilizing, and Watering During seedling growth, pay attention to weeding and loosening the soil to improve soil aeration. Weeds must be removed early, and cultivation should be shallow hoeing without damaging seedling roots, and soil from the furrows should be banked onto the seedbed, banking up gradually to thicken the soil layer. Each time weeds are removed, apply soil fertilizer once and water with liquid fertilizer once. Apply 3-10 kg of urea and 1-5 kg of potassium chloride per mu mixed with water, and it can also be diluted for foliar spraying, with the seedbed surface being sprayed wet as the standard. Water management depends on dry and wet conditions, and late irrigation and early drainage should be carried out so that the nursery always remains moist.
2.4.5 Leaving the Nursery Through careful management, 1-year-old seedlings with a height of 15-35 cm, a ground diameter of 0.3 cm, and 3-5 side branches can leave the nursery. Each mu produces 120,000-150,000 high-quality seedlings.
3 Seedling Propagation Results
Since the Lianshan County Forestry Bureau implemented the "Lianshan County Taxus wallichiana var. mairei Improved Variety Selection and Breeding" project, it has selected two seedling bases, Wanliping in Shangcao Village, Yonghe Town, and the Hedong Forestry Farm, with a total area of 60 mu. Through several years of experimentation, it has basically mastered the seed sowing and seedling techniques for Taxus wallichiana var. mairei, with a survival rate of no less than 90%. From 2004 to now, 500,000 Taxus wallichiana var. mairei seedlings have been successfully cultivated. Starting in 2005, Lianshan County provided seedlings to the Dinghushan National Nature Reserve in Zhaoqing City and the Fengkai Heishiding Nature Reserve, and began small-scale planting of Taxus wallichiana var. mairei in the Lianshan County Bijia Mountain Provincial Nature Reserve and the county seat Jinfeng Mountain leisure area. At present, the growth is good.
Seed Propagation Techniques for Taxus wallichiana var. mairei
Taxus wallichiana var. mairei combines medicinal, timber, and ornamental uses and has high development and utilization value. Because its seed coat has poor permeability, a long dormancy period, and seed propagation is difficult. But as long as the biological characteristics of Taxus wallichiana var. mairei are mastered and operations are strictly carried out according to technical regulations, seedling propagation will certainly succeed. The specific operations are as follows:
I. Nursery Site Selection and Fertilization:For nursery site selection, it is best to choose rice fields with deep soil, loose structure, rich organic matter, good drainage, and no western sun exposure (it must be rice field soil from the same year's harvest). After harvesting mid-to-late rice, deeply plow once when the soil is dry, break up the soil once, and then divide into compartments and make beds. Wide bed 1.5 m (net bed surface width 1.2 m, path width 0.3 m); bed height 20 cm, and the length of the seedbed depends on the nursery site. While preparing the land and making beds, apply about 8,000 jin of decomposed pig and cattle manure per mu, 200 jin of quick-dissolving high-quality compound fertilizer, and mix in 6 to 8 jin of carbofuran to control underground pests. After
turning and mixing the fertilizer into the soil layer and leveling the bed surface, fill the bed surface with yellow subsoil to a thickness of 5 cm.
II. Timely Sowing:After one year of storage, some seeds have cracked openings. At this time, sieve them out and wash them clean, soak and disinfect with 0.05% potassium permanganate solution for 10 minutes, then rinse clean with clear water, and sow after drying.
Sowing is divided into two types: broadcasting and drilling:Broadcasting is evenly scattering the seeds on the seedbed filled with yellow subsoil, covering the seeds with yellow subsoil until the seeds are no longer visible, then covering the entire seedbed with moss. For drilling, select a 15 cm wide wooden board and press sowing furrows into the seedbed filled with yellow subsoil, 2 cm deep, with a distance of 15 to 20 cm between sowing furrows. Evenly sow the seeds into the furrows, cover the seeds with yellow subsoil to a thickness of 1 cm, then cover the sowing furrows with moss.
It should be noted that:
First, strictly control the sowing rate:Use 15 kg of seeds per mu, otherwise it will seriously affect the qualification and emergence rate of 2-year-old seedlings;
Second, after sowing:For broadcasting, the entire seedbed must be covered with moss; for drilling, only cover the sowing furrows with moss. After the seedlings emerge, do not remove the moss either; keep it on the seedbed for a long time.
The advantages of moss protecting seedlings are:Protecting the seedbed from rain splash and direct sunlight, preventing seedlings from sunburn and avoiding suffocation and death caused by mud sticking to stems and leaves to form mud sticks, and often keeping the soil loose and moist, reducing the labor of cultivation and weeding. However, the moss covering should be thin, not too thick. If there is a long drought without rain, fine loess can be used to press down the moss, or a sprayer can be used to spray water to keep the seedbed moist.
III. Field Management: 1. Shading of Seedlings:Before the seedlings emerge, the shade frame must be set up well, with a frame height of 1.7 m. During the dog days, the seedbed must be shaded.
2. Pest and Disease Control:After the seedlings emerge, it is the rainy season. Because there is much rain and high air humidity, the seedlings are susceptible to infection by pathogens causing root rot and damping-off disease, resulting in total failure of seedling propagation. Therefore, the emphasis is on "prevention," that is, 7 days after the seedlings emerge, spray 800 times thiophanate or half-strength Bordeaux mixture (0.5 copper sulfate, 0.5 jin lime, 100 jin water), spraying on the seedling stems and leaf undersides and leaf surfaces.
3. Cultivation, Weeding, and Fertilizing:During seedling growth, pay attention to weeding and loosening the soil to improve soil aeration. The principle of weeding is: remove small, remove early. For topdressing in the early stage of seedling growth, mainly use nitrogen and phosphorus fertilizers, prepared with 10% dilute human waste plus 0.4 jin urea, applying once every half month. Stop applying in mid-September, remove the shade net, and keep the frame for use next year.
4. Transplanting of Seedlings:If sowing is uneven, causing seedlings to be too dense or too sparse, transplanting must be carried out from late May to mid-June, thinning where dense and filling in where sparse.
The transplanting method is:Choose a cloudy or rainy day or after rain for transplanting. After covering well with moss, rinse the root ball with clear water, and transplant.
IV. Management of 2-Year-Old Seedlings:Before transplanting the seedlings, set up the shade frame well, and promptly clear weeds in the paths and around the area. Increase topdressing for weak seedlings to promote growth. Through careful management, 1-year-old seedlings are 12 to 25 cm tall, and 2-year-old seedlings are 30 to 35 cm tall, with a ground diameter of 0.5 cm, and the seedling yield per mu reaches 60,000.
Cutting Propagation Techniques for Taxus wallichiana var. mairei
Taxus wallichiana var. mairei is a slow-growing tree species and is also a dioecious plant. Its seed production is small, and the embryo post-ripening dormancy period is long, with problems such as uneven seed germination and low germination rate. However, the recent development of raw material forests for Taxus wallichiana var. mairei is based on the strategy of utilizing densely planted seedlings, so adopting large-scale cutting propagation is the foundation for realizing this strategy. Its cutting propagation techniques are described below. 1. Cuttings For Taxus wallichiana var. mairei, the best method is leafy hardwood cuttings from young plants.The best cuttings are fully lignified 1-year-old branches and 2-year-old branches; 3-year-old branches can also be used; but using branches 4 years or older as cuttings significantly reduces rooting ability and is no longer suitable. For cuttings, sprouting branches are best, followed by lateral branches at the top. Branches used as cuttings are best if thick and strong; overly thin and weak branches are not suitable. Generally, branches with a diameter below 2 mm are difficult to handle and not easy to survive. Special experiments on cutting length showed that cuttings shortened to 1 cm could also root, and even 3 plants with single-leaf petioles rooting appeared. Taxus wallichiana var. mairei is a tree species that roots easily from cuttings. For cuttings of 1 cm, 3 cm, 5 cm, and 10 cm lengths, both the rooting rate and seedling growth increase with the increase in cutting length. Therefore, in production, branches 5-20 cm long can be flexibly cut as cuttings according to the amount of cutting resources and seedling demand. Moreover, relatively short lateral terminal branches can all be used. The success of short-cutting experiments provides a basis for improving the utilization rate of cutting branches in actual production. For the cut cuttings, remove the leaves from the portion inserted into the soil. Grade them and bundle them in groups of 50 for pre-planting treatment and transport. Implementing graded cutting and graded management is an important measure to improve the seedling survival rate and reduce production costs.
2. Cutting Substrate River sand, perlite, and soil used as substrates for Taxus wallichiana var. mairei cuttings have all achieved success, among which soil is the best cutting substrate. Alpine meadow soil, brown earth surface soil under alpine coniferous forests, mountain red soil, yellow soil, yellow-red soil, vegetable garden soil, etc. can all be used as substrate soil, among which loose, fertile alpine meadow soil, brown earth surface soil, and vegetable garden soil are best. They can be selected according to local conditions. In the cutting bed, lay a substrate with a thickness of 15 cm, and for this purpose the soil bed preparation depth should be 20 cm.
3. Treatment of Cuttings and Cutting Bed
(1) Cutting Treatment To avoid soaking cuttings in large containers for a long time during large-scale cutting, a relatively high-concentration plant growth hormone is used for dipping the cuttings. Before treatment, first dip the cuttings in 600-750 times solution of 75% wettable chlorothalonil powder, shake dry, then dip in 500 mg?L-1 No. 2 ABT rooting powder or indolebutyric acid, shake dry, and then carry out cutting. Carbendazim or 25% wettable powder 400 times solution can also be used to disinfect the cuttings.
(2) Cutting Bed Treatment 2-3 days before cutting, mix a small amount of quicklime (10 g/m2) or potassium permanganate solution (0.03%) into the cutting bed for soil disinfection.
4. Cutting Season, Density, and Key Points
(1) Cutting Season There are successful examples of Taxus wallichiana var. mairei cutting throughout the year, but in most areas of Yunnan, spring cutting is best. If land is prepared in January-February, cuttings are collected and inserted after the Spring Festival, and completed by early April. Cuttings can root before July, and leave the nursery at the beginning of the rainy season one year later, which is the best arrangement.
(2) Cutting Density The cutting density is mainly selected according to the size of the cuttings. The maximum cutting density implemented had a plant-row spacing of 2 cm×5 cm, and 500,000 cuttings could be inserted per 666.7 m2. A spacing of 4 cm×5 cm and 4 cm×6 cm is a moderate cutting spacing; with this spacing, 250,000 and 210,000 cuttings can be inserted per 666.7 m2.
(3) Key Points of Cutting Use vertical insertion, with the insertion depth based on being able to stabilize the cutting; generally the insertion depth is 1/3-1/2 of the cutting length. When cutting, make a template with the same width as the cutting row spacing (such as 5 cm, 6 cm) and marked with a scale, and use it during cutting so as to cut by rows and achieve uniformity. The cutting depth is controlled by inserting the cutting deeply into the soil while pinching the cutting with the fingers, with the fingers not pinching the cutting being able to touch the soil surface. After a bed is fully inserted, promptly water thoroughly. Not only should the cutting layer soil be soaked through, but the loosened soil should also be brought into close contact with the cuttings, which is the same principle as watering the "root-setting water" thoroughly when planting seedlings.
5. Cutting Nursery Facilities The cutting nursery facilities can be varied, and the basic requirement is to reasonably control temperature, humidity, and light. Through years of practice and improvement in various places, the basic facilities suitable for large-scale cutting seedling nurseries in mountainous areas are: shade shed (net), temperature shed, and irrigation network.
(1) The role of the shade shed (net) is to shade and cool the seedbed. The shading degree should be determined according to the climate of each place and the temperature conditions during the seedling period, and the shading degree is 50%-90%. After the cuttings root, gradually reduce shading to benefit seedling growth. The shade shed (net) can use commercially available film shade nets, or local materials such as bamboo and wood frames and branches and leaves can be used to build it.
(2) The role of the temperature shed is to increase the temperature and humidity of the seedbed. Cutting propagation can be carried out in various large greenhouses and temperature sheds. Generally, bamboo is used to build film arched sheds. The two most commonly used are the high shed (2 m high) and the low shed (0.5 m high). The high shed has doors at both ends, and the low shed is completely closed; when managing the seedbed, the film needs to be lifted for operations. There is also a double-layer shed in which a small temperature shed is built inside a large temperature shed. In Nyingchi, Tibet, even triple-layer temperature sheds are used to achieve insulation. Thermometers and hygrometers should be placed both inside and outside the shed to accurately grasp temperature and humidity. The temperature shed should be sealed, and it is suitable if water mist can form on the temperature shed film (indicating that the air humidity inside the shed has reached saturation).
(3) The irrigation network should be able to irrigate and drain, not allowing the cutting bed to accumulate water or become too dry. It is best to use pipes and spray irrigation; flowing water flooding irrigation and soaking the seedbed are prohibited.
6. Post-Cutting Management
(1) Control of Temperature and Humidity The best temperature is a stable 25-30°C. If the temperature is below 10°C, the cuttings may not root; if below 20°C or above 30°C, measures should be taken to increase or decrease the temperature. The main measures for increasing temperature are reducing the shading of the cutting bed, or adding straw mats at night; the main measures for decreasing temperature are increasing the shading of the cutting bed and spraying water, opening the temperature shed door, or lifting the temperature shed film. The soil moisture of the cutting bed is best near saturation, but do not flood it; the minimum relative humidity of the air should be maintained above 80%. When the temperature rises at noon, the relative humidity will drop significantly. If it drops below 60%, water (mist) should be sprayed appropriately, which can both humidify and cool. A closed temperature shed can maintain a high-humidity environment inside the shed for a long time, which is beneficial to the rooting of Taxus wallichiana var. mairei cuttings. Water mist condensation on the temperature shed film indicates high humidity inside the shed; water again when there is no water mist.
(2) Weeding The cutting nursery chooses fertile land, and weeds grow especially quickly and lushly on fertile land. Therefore, weeding is an important measure in nursery management, with the principle of "remove early, remove small, remove completely" to prevent vicious competition between weeds and seedlings.
(3) Topdressing If the cutting bed soil is fertile, topdressing may not be needed. However, if rooting is too late or after the seedlings have rooted, spraying low-concentration potassium dihydrogen phosphate and urea on the leaf surface has the effect of promoting seedling growth.