Detailed Cultivation Techniques for Propagation, Pest and Disease Control of Camellia chekiangoleosa
Propagation and Pest and Disease Control Cultivation Techniques of Camellia chekiangoleosa
Fund project: 2015 Central Financial Forestry Science and Technology Promotion Demonstration Fund Project "Improved Variety Breeding and Cultivation Technology Promotion of Camellia chekiangoleosa" (2015-HBTG05).
1 Biological Characteristics of Camellia chekiangoleosa
Evergreen shrub or small tree, tree height can reach 7 m. Bark grayish-whitein color and smooth; leaves oblong, smooth and hairless on both sides, margins sparsely bearing shortserrations; flowers bloom from late winter to spring, red or pink, single flowersterminal or axillary, petals 6-8, obcordate. Capsule spherical,hairless, pericarp woody, diameter 4-6 cm, single fruit weight 26-160 g.
2 Suitable Growing Conditions for Camellia chekiangoleosa
Camellia chekiangoleosa prefers a warm and humid environment. In Hubei Province, the suitablerange is low mountain hills at an altitude of 500-1,000 m, with an annual average temperatureof 14-17 degrees C, precipitation >= 1,000 mm, relative humidity 70%-80%, frost-free period 220-270 d. The soil is best as loose, fertile, moist,well-drained mountain yellow soil, yellow-brown soil, sandy loam, red soil and other acidicsoils, with a soil layer thickness of more than 60 cm, pH value 5-6.5, slopeaspect as sunny slope and semi-sunny slope, slope gradient below 25 degrees.
3 High-Yield Cultivation Techniques for Camellia chekiangoleosa
3.1 Variety Selection
Priority is given to selecting superior clones and superior individual plants bred by the Research Institute of Subtropical Forestry, Chinese Academy of Forestryas seed sources. Their main economic and technicalindicators are: average fresh seed yield rate 22.0%; kernel oil content65%, average 100 kg fresh fruit contains 3 kg oil; average oil yield at full fruit stage１５ｋｇ／ｈｍ２。
3.2 Seedling Raising Techniques for Camellia chekiangoleosa
Seedling raising of Camellia chekiangoleosa is divided into: sowing seedling raising, cutting seedling raising, graftingseedling raising. In production, grafting seedling raising is the main method, mostly using light substrate bud seedlingrootstock grafting for seedling raising.
3.3 Afforestation Techniques for Camellia chekiangoleosa
(1) Selection of afforestation site: The afforestation site should be selected in hilly areas at an altitude of 500-1,000 m, requiring sufficient sunlight, slope gradient below 25 degrees,deep soil layer, loose texture, slightly acidic (pH value 5-6.5)plots. Steep mountain slopes, shady slopes and low-lying waterlogged land must not be selected.
(2) Site preparation: The site preparation time is before October. After site preparation, it is best to sun-dryfor one month before digging holes. The main site preparation methods are the following three. (1) Fullreclamation site preparation. For low mountains and gentle slope land with a slope of less than 10 degrees, full reclamationsite preparation is implemented. The forest land is comprehensively deep-plowed more than 20 cm, then according to the plannedrow spacing, holes are dug at fixed points, and the planting hole specification is 60 cm x 60 cm x60 cm. (2) Strip reclamation site preparation. For forest land with a slope exceeding 10 degrees, terraced sitepreparation is used. For forest land with a slope of 10-15 degrees, the terrace surface width is 3-6 m, and holes are dugon the strips; for forest land with a slope of 15-20 degrees, the terrace surface width is 1.5-2.0 m, and then holesare dug on the strips. The terrace surface width, distance between terraces and distance between holes are determined according to terrainand planting density. The hole digging specification is the same as full reclamation. (3) Hole reclamation site preparation.For plots with little original vegetation, concentrated precipitation, severe water erosion, wind erosion and soil erosion,hole reclamation site preparation is adopted. Along contour lines, holes are dug at fixed points according to plant spacing and row spacing,with the same specification as full reclamation.
(3) Afforestation density: It is mainly determined according to the biological characteristicsof Camellia chekiangoleosa, site conditions and afforestation purpose, etc. Generally, 80-120 plants/667 sq m are planted.
(4) Base fertilizer: In order to improve soil fertility, promote seedling growth,and achieve high yield as early as possible, after digging holes, appropriate application of garbagefertilizer, rice straw and farmyard manure 3-5 kg may be carried out according to local conditions, with 0.25-0.30 kg of compound fertilizer added to each hole, then backfill with topsoil, fill the hole to form a steamed bun shape, foruse during afforestation.
(5) Seedling selection: For the quality grade specifications of Camellia chekiangoleosa seedlings, seeTable 1. It is required to select Grade I and Grade II qualified seedlings for afforestation, and it is recommended to use lightsubstrate bud seedling rootstock grafted seedlings for afforestation.
Table 1 Quality Grade Specification Indicators of Camellia chekiangoleosa Seedlings
(5) Seedling planting: The planting time for cutting seedlings and sowing seedlings is bestfrom December to January, and no later than mid-March. For container seedling afforestation,the period from late October to before the end of May of the following spring is acceptable, withearly March to late April being the best. When planting, ensure roots are spread, seedlingsare upright, and soil is firm. Seedlings should not be planted too deep, and it is suitablefor the graft interface to be level with the ground. After planting, water thoroughly to settle the roots.
3.4 Tending and Management of Camellia chekiangoleosa
(1) Tending and management of young forests: (1) Replanting. In the spring of the second year after afforestation,replant, using strong seedlings of the same age to fill in and complete diseased and missing plants. (2) Water, soil and fertilizermanagement. After afforestation, attention should be paid to drainage during the rainy season, and timely irrigation should be carried out during summer and autumn droughts.In the first year after afforestation, in order to protect the root system, weeding must not be carried out in summer, andweeding is carried out after September. From the second year onward, tending is carried out 1-2 times per year, the first timein May-June, and the second time in August-September. It mainly includes loosening soil, weeding, earthing up,and expanding holes. During the young forest period, green manure, medicinal materials,oil crops and other crops can be interplanted using gaps between trees. In winter, apply 10-20 kg of farmyard manure per plant, and before spring shootssprout, apply additional nitrogen fertilizer. The ratio of nitrogen, phosphorus and potassium is best at 2:1:1. (3)Tree shape cultivation. When the seedling height after planting reaches 40-50 cm, pinch off the growing tip to set the trunk.
In the first year, at 30-40 cm, select and retain 3-4 strong-growing, reasonably positionedlateral branches to cultivate as main branches; in the second year, retain2-3 strong branches on each main branch as secondary main branches; in the 3rd-4th years, on the basis of continuingto cultivate the main and secondary main branches, cultivate the strong spring shoots on them aslateral branch groups, and make the proportions among the three reasonable and evenly distributed, forming a lowand short natural round-headed and open-center tree crown. In the first 3 years, young trees need to haveflower buds removed to maintain vegetative growth of the tree body and accelerate crown formation.
(2) Tending and management of mature forests: (1) Reclamation. Winter reclamation is from November toJanuary of the following year, and can be strip reclamation, hole reclamation and trench reclamation, with a depth of 20-25 cm; summerreclamation is from May to July, with a depth generally of 10-15 cm, requiring shallow hoeing.
(2) Pruning. Camellia chekiangoleosa is not suitable for heavy-intensity pruning. Removedead branches, diseased and pest branches, leggy branches and high forked branches, and cultivate a natural open-center tree shapeor natural round-headed tree shape.
(3) Fertilization. During the full fruit stage of mature Camellia chekiangoleosa forests, in order to adapt to the needsof vegetative growth of the tree body and mass flowering and fruiting, fertilization should have a reasonable ratio of nitrogen, phosphorus and potassium,generally N:P:K at 10:6:8. Each year, apply a total amount ofquick-acting fertilizer of 1.5-2.0 kg per plant, and organic fertilizer 15-20 kg.Increasing the application of organic fertilizer can not only effectively improve the physical and chemical properties of the soil, increase soilfertility, increase the number of soil microorganisms, and prolong fertilizer efficiency, but also increasethe oil content of the fruit.
(3) Bee pollination: Camellia chekiangoleosa mainly relies on bees, ants and other insects forpollination. First, beneficial pollinating insects should be protected; second, bees should be keptaround the forest land, which can both increase economic income and meet the pollinationneeds of Camellia chekiangoleosa, improving the fruit-setting rate.
4 Main Pests and Diseases and Control
The main diseases of Camellia chekiangoleosa are anthracnose and sooty mold, and the mainpests are camellia geometrid and tea shoot moth. The principle of "prevention is more important than treatment"should be implemented, with cultivation techniques as the foundation, and integrated control measurescombining biological and chemical control. Protect and utilize natural enemies for biological control.
5 Fruit Harvesting
The fruit maturation time of Camellia chekiangoleosa ismid-September. Immature fruits, after harvesting,have low yield, low oil extraction rate and poor quality. Early picking is strictly prohibited. When theouter pericarp fuzz of Camellia chekiangoleosa falls off, the color darkens, the luster brightens, the outer pericarpchanges from green-yellow to red or red-brown, and the kernel hardens, it is mature.When picking, use a small knife or small hook to pick. It is strictly prohibited to break branches or strike the treetrunk and damage the tree body, so as not to affect new flower buds and next year's yield.Do not pick fruits and randomly strike with poles. After the fruits are brought back, they should be dried in time for threshingto remove impurities, and after they are fully dried, they are stored for oil pressing. Seeds used for seedlingraising must not be exposed to intense sunlight, and should be stored in sand for later use.