Camellia oleifera is an important woody oil tree species endemic to China and vigorously developed by the country, mainly distributed in Guangxi, Jiangxi, Hunan and other southern provinces and regions. At present, there are about 386 Camellia oleifera forests in China70,000 hectares. There are a large number of falling flowers and fruits in the production of Camellia oleifera, and it is often possible to find full of flowers, but there are few hanging fruits. According to the test: Camellia oleifera flower drop 10%-25%, fruit drop up to 15%-20%, serious area plantsMore than 80% of flowers and fruits are dropped, and even some of the whole plant is lost. By analyzing varieties, pollination, forest age, climate, soil, cultivation techniques, pest and disease damage, mechanical damageand other external factors and physiological factors, in order to provide reference for the high-yield cultivation of Camellia oleifera.
1. The reason why Camellia oleifera does not bear fruit when it blooms lightly
There is a situation of "a thousand flowers and one fruit" in Camellia oleifera, which seriously restricts the increase of Camellia oleifera production. How to solve the problem of "a thousand flowers and one fruit" of Camellia oleifera and make it stable and increase production to achieve significant results is the key to making the Camellia oleifera industry bigger and stronger.
There are two main reasons why Camellia oleifera does not bear fruit:
First, the pregnancy rate is not highCamellia oleifera is an insect-borne flower, and it can only be pollinated by different flowers, and it begins to bloom in mid-October, and is in full bloom in November, and the flowering is basically over in late December, and a few are extended to open in February of the following year. Blooms are generally from 9 a.m. to 2 p.m. throughout the dayIt is at its peak between 11 a.m. and 1 p.m., when temperatures are warmer, which is conducive to flower opening, pollination and insemination. It takes 6-8 days for a flower to go from bud to bud.
Second, there are few pollinating insects. Camellia oleifera is an insect-vectored, cross-pollinated tree speciesThe insects that help pollinate mainly include ground bees, large tongue wasps, Chinese honey bees, small flower bees, yellow-striped slender-waisted bees, fruit flies, meat flies, hemp flies and butterflies.
From the Xi of flowers, it can be seen that in order to improve the fruiting rate, the premise is to increase the pollination rate, especially to protect the pollinating insects, and the main factors affecting the survival of pollinating insects are currently considered to be the following in the construction of the base
1. The impact of total land reclamation, especially large-scale contiguous areas, on the nesting and activity range of pollinator bees.
2. Before land preparation, refining the mountain will cause the original pollinator bees to die or be driven away.
3. The effect of long-term use of pesticides or herbicides on the nesting and growth of pollinating bees.
2. Influencing factors of Camellia oleifera flower and fruit drop
1. Falling buds
The main reason for the fall of Camellia oleifera is the loss of balance of water and nutrients in the physiological process.
The survey found that if there is only one flower bud at the top of the spring shoot, it generally does not fall buds;
If there are many buds, the flower buds on the lower part of the branch tend to fall off;
The spring shoots continue to grow, and the budding rate of the summer shoots reaches 455%；
The bud drop rate of spring shoots is only 51%。
At the same time, the lack of soil moisture will also cause flower buds to fall off, such as continuous high temperature and drought weather in summer and autumn will lead to a large number of buds of Camellia oleifera trees.
From the point of view of the law of bud fall, the most serious bud fall in August is because it is at this time when Camellia oleifera fruit grows oil and flower buds develop rapidly, and a large amount of water and nutrients are consumed. At this time, continuous high temperature and drought often cause dehydration and fertilizer shortage, which aggravates the degree of sheddingThere are also more buds in November, which is the ripening of tea fruits in October, and then enter the full flowering period, and the nutrients are consumed too much, and the supply is not available for a while and some of the original nutrient buds fall off.
2. Falling flowers
1) Camellia oleifera is a cross-pollinating plant, and the main reasons for flowering fall are the lack of flowering period, low pollination affinity or self-incompatibility between varieties.
2) Temperature, humidity, wind speed, etc. can affect the activity of pollinating insects and pollen transmission. When the absolute temperature of the flowering period is 10-15, the pollination is normal and the flowers fall less, generally about 10%;When the absolute temperature drops below 10, the pollination rate is significantly reduced, and the number of flowers dropped reaches more than 70%.
3) Fertilization, pruning, water regulation, pest control and other cultivation measures can effectively improve the fruit setting rate of Camellia oleifera. Sufficient water and fertilizer conditions can ensure the nutrients required for flowering, pollination and fruit setting of Camellia oleiferaReasonable pruning can promote the growth and development of camellia flowers and fruits by balancing nutrient distribution, improving ventilation and light transmission conditions, and reducing diseases and pests.
3. Fruit drop
There are many factors affecting the fruit drop of Camellia oleifera, on the one hand, the two peak periods of physiological fruit drop of Camellia oleifera itself, which are in March and July and August, respectively. On the other hand, affected by factors such as variety, nutrients, water, climate, diseases and pests, such as drought, insufficient nutrients in the tree, anthracnose, fruit boring pests and other unfavorable factors will lead to a large number of fruit drop of Camellia oleifera.
3. Technical measures for Camellia oleifera flowers and fruits
1. Reasonable variety combination
Camellia oleifera is an alienated pollination plant, and multiple varieties need to be configured in a certain proportion to ensure its high fruit setting rate in afforestation, so as to achieve the effect of high yield and stable yieldThe low fruit setting rate of Camellia oleifera caused by the lack of flowering periodLow yields are more common. Therefore, the afforestation of Camellia oleifera should select varieties that meet in flowering period and have good mutual pollination and fertilization between varieties, and at the same time, multi-variety allocation should be carried out according to the characteristics of different varieties.
2. Improve pollination conditions
First, during the flowering period of Camellia oleifera (October to December every year), you can choose a suitable bee colony to carry out artificial bee release in the Camellia oleifera forest to assist pollinationOr stocked with Italian bees with Camellia oleifera nectar tolerance.
The second is to improve the stand conditions of Camellia oleifera and increase the ventilation and light transmission conditions to provide a good activity space for pollinating insects and increase the spread range of pollen.
3. Nutritional balance regulation
(1) Strengthen fertilizer and water management
In order to ensure sufficient nutrients for Camellia oleifera, fertilizer needs to be applied 2-3 times a year, and 2-3 kg of organic fertilizer is applied from December to January of the following year
In the spring, compound fertilizer (total nitrogen, phosphorus, potassium not less than 30%) 05-1 kg strains ;
In June, phosphorus and potassium compound fertilizer were applied 03-0.5 kg of plants is fruit preservation fertilizer.
Timely irrigation in the dry season and timely removal of stagnant water in the rainy season to maintain the vigorous growth of the tree, promote fruit development, and carry out good tree disc coverage to reduce the degree of abnormal fruit drop and maintain soil moisture.
(2) Scientific pruning
Through reasonable tree cultivation measures such as pruning and shaping, the spatial distribution of branches and leaves tends to be reasonable and can be reducedSoft rot, anthraxoccurs, thus preventing fruit dropping. Scientific tree cultivation measures such as plastic pruning can increase the yield by 26%-919%, at the same time, can effectively adjust the size of the year.
(3) Thinning flowers and fruits
The number of camellia flowers is far more than the number of final fruits, and the number of Camellia oleifera flowers is generally largeThe natural fruit set rate is around 30%.。Too much flowering and fruiting of Camellia oleifera will lead to a shortage of nutrients, yellowing of tree leaves, a large number of fallen leaves, etc., which is easy to destroy the tree potential, and reduce or even stop production in the following year, resulting in serious annual phenomenon, and affect the normal development of fruits, forming many small fruits and secondary fruits with poor growth and low oil content. Therefore, in addition to the natural shedding of stunted flowers and young fruits due to the regulating ability of Camellia oleifera itself, it is also necessary to remove excess flowers and fruits in order to meet the production requirements. Generally, the flowering time is 10-11 months, and the fruit thinning time is 3-4 months.
4. Regulation of exogenous hormones and nutrients
Spraying plant growth regulators and nutrients during the flowering period of Camellia oleifera can improve the fruit setting rate of Camellia oleifera. In the flowering period of Camellia oleifera, that is, from November to December every year, spray foliar fertilizers or growth regulators such as plant growth regulators, boron fertilizers, potassium dihydrogen phosphate, and Camellia oleifera fruit preservation agents, and spray them once every 15-20 days.
5. Prevention and control of pests and diseases
Soft rot, anthracnose, all kinds of fruit borer pests and other pests and diseases can cause a large number of fruit drop of Camellia oleifera.
To prevent and control soft rot and anthracnose, we should first strengthen tending and management measures to enhance tree potentialDuring the onset of the disease, no nitrogen fertilizer is applied, and phosphorus and potassium fertilizer are addedRemove diseased leaves, branches, and fruits in a timely manner and burn them for landfill. In the early stage of soft rot, spray 600-800 times of 1% Bordeaux solution and 300 times of carbendazim, spray once every 5-7 days, 3 times in a row;In the early stage of anthrax, systemic fungicides such as carbendazim 50% can be used to prevent and control anthrax. At the same time, the prevention and control of C. oleifera leaf-eating pests, C. oleifera stem borers, blue-winged beetles, Camellia oleifera cotton scales, tea seed weevils and Camellia oleifera bees can be comprehensively controlled, and artificial capture, poisonous bait and light trapping, low-toxicity and high-efficiency pesticide control methods can be comprehensively adopted.
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