Torreya nuts bear fruit once every three years; what are the cultivation methods?
Torreya nut, also known as Bizi, Feishi, Pizi, Yushan fruit, Chiguo, Yufei, Xiangfei, wild Chinese fir seed, Mufei, etc., is the dried mature seed of the plant Torreya grandis Fort. of the yew family (Taxaceae). It is harvested in autumn when the seeds mature, the fleshy aril is removed, and the seeds are washed clean and sun-dried. Its taste is sweet, and its nature is neutral; it enters the Lung, Stomach, and Large Intestine meridians; it has the effects of killing parasites and reducing food stagnation, moistening the lungs and stopping cough, and moistening dryness and relieving constipation. It is mainly used for hookworm disease, ascariasis, taeniasis, abdominal pain due to worm accumulation, malnutrition in children, cough due to lung dryness, and constipation. It is mainly produced in southern Jiangsu, Zhejiang, northern Fujian, northern Jiangxi, southern Anhui, and westward to southwestern Hunan and Songtao in Guizhou, and other places. It grows on hillsides, and both wild and cultivated varieties now exist. It is a medicinal and edible dual-use medicinal material. There is a folk saying that Chinese Torreya "bears fruit once every three years," which actually means that from the formation of the flower bud primordium to fruit maturity requires going through 3 years. The Chinese Torreya tree has luxuriant branches and leaves, a long lifespan, and is a beautiful evergreen tree, making it an important economic tree species and ornamental tree species. As a Torreya nut widely used for medicinal, edible, and ornamental purposes, how is it cultivated? The following is an introduction to the cultivation and harvesting and processing techniques of Torreya nut, which bears fruit once every three years:
[Cultivation Techniques]
I. Site Selection and Land Preparation
The nursery site requires convenient transportation, deep soil layers, and sufficient water sources. To ensure the implementation of construction and irrigation measures, a power supply is required. Before sowing, prepare the seedbed and apply sufficient base fertilizer, mainly farmyard manure, at 40-50 loads per mu. The seedbed is about 1.5 m wide and about 15 cm high.
II. Planting Methods
1. Seed Collection and Seed Treatment
When selecting seeds, choose according to seed color. Generally, when the fruit aril changes from green to yellow-green, it is more suitable as seed for raising seedlings. After the seeds are harvested, first remove the aril, then carry out stratified sand storage of the seeds, maintaining moderate dryness and moisture. Sand-stored seeds generally begin to germinate successively in late November, and by the end of March of the following year the germination rate can reach more than 90%. When the radicle grows to 0.5-1.5 cm, they can be sown.
2. Sowing Methods
Before sowing, the seeds should first be disinfected. They can be soaked in a 0.2% potassium permanganate solution for 10 min, then removed and washed clean with clean water. The sowing spacing is 15 cm × 30 cm. Place the seeds horizontally with the radicle facing downward, cover with shallow soil (about 3 times the transverse diameter of the seed), and cover with rice straw to keep the bed surface loose and moist.
III. Field Management
1. Seedling Stage Management
After the seedlings emerge from late April to early May, a shade shed should be built in time. The shade shed is 1.8 m high, with 50%-60% light transmission. During drought, water thoroughly once every 10-15 days, and sprinkler irrigation is preferable as the watering method. During the seedling stage, fertilizer can be applied appropriately, with urine and manure being the best. For the pest cutworm, 2 g/m2 of Dexon can be mixed with loess and spread at the roots for control. Torreya seedlings are also prone to root rot during the moldy season. First manually remove the diseased plants, then apply a mixture of wood ash and lime at a ratio of 8:2 at 100-150 kg/mu to the roots of the seedlings, which can prevent spread.
2. Planting and Management
Intertillage and weeding should be carried out every year, with hilling and topdressing. After 5 years of field planting, grafting, pruning, and trimming must be carried out.
[Pest and Disease Control]
I. Diseases
1. Green algae: The harmful mode of green algae is to form rough, gray-green moss-like material on the branches and leaves of Torreya trees, affecting the normal photosynthesis of the leaves, causing insufficient nutrient supply to the Torreya fruit, and leading to fruit drop and reduced yield. Green algae mostly occur on old leaves of Torreya trees and cause relatively light damage to new leaves. During the plum rain season, due to continuous overcast and rainy weather, green algae are likely to occur. The incidence rate of Chinese Torreya green algae is 51%-64%, mainly mild occurrence, with the peak incidence from late June to early July. Under moist and warm conditions, the shady side of hillsides, valleys with insufficient light and damp darkness, and Torreya forests planted too densely or growing too closed are conducive to the breeding and spread of green algae. In addition, Torreya forests with extensive management and poor ventilation and light transmission are also conducive to the occurrence of green algae.
Control method: Spray pesticide for control in early June before the plum rain season arrives, or when it clears up between rains, once every half month, spraying continuously 2-3 times to achieve the control effect. Using an 800-fold dilution of crystal lime sulfur mixture to control green algae has an obvious effect.
2. Bacterial brown rot: This disease mainly harms the fruit. It begins to occur in early May, with the peak incidence in mid- and late May. From mid-May to mid-June it causes fruit drop, with the peak fruit drop period from late May to early June. Needle-head-like oil-soaked spots appear on the fruit surface, and after peeling off the epidermis, the subcutaneous tissue can be seen turning purplish-brown. After 2-3 days, the spots expand into patches or strip-shaped rusty-brown lesions, slightly sunken, with bead-like mucus overflowing. The fruit skin gradually changes from green to gray-yellow. After invading the kernel, the damaged part turns purplish-brown and then falls off. When the disease occurs later or more lightly, only scars form on the fruit surface or deformed fruit results, which generally do not fall off, but affect the continued development of the fruit and the improvement of quality.
Control methods: (1) Before the disease occurs, spray the tree canopy with an 800-fold dilution of zineb, or a 1000-fold dilution of "402" antibacterial agent. Depending on the disease situation, thereafter spray 1-2 times every 1-2 weeks, which has a certain control effect. (2) In early to mid-April, spray the tree canopy with a 5000-fold dilution of "Aiduoshou" to enhance tree vigor and resistance.
3. Root rot: This disease occurs frequently in nursery seedlings from May to July.
Control methods: Before raising seedlings, disinfect the soil with quicklime or a 100-fold dilution of 75% Dexon wettable powder. When the disease occurs, dig out and remove the diseased plants, and spray or drench with a 5%-10% copper sulfate solution to prevent spread.
4. Stem rot: Mainly caused by high-temperature and high-humidity weather from June to August, harming seedlings and young trees.
Control methods: Adopt protective measures such as covering the root zone with grass, shading, and strengthening fertilizer and water management.
5. Sclerotial root rot (purple root rot): When the disease occurs, the root system is covered by a mycelial network, preventing the roots from ventilating and causing root rot, so it is commonly called "net vein." It generally begins to occur in June, and in severe cases can cause the entire Chinese Torreya plant to wither and die. Acidic clayey soil and intercropping with potato crops make infection easy. Planting Chinese Torreya in plots where potato crops were previously grown and "net vein" occurred is also prone to this disease.