First, young tree management

Litchi can be delayed for 5-7 years from planting to economic fruiting. If cultivation management and pest control are strengthened, it can enter the economic flowering and fruiting period in the third year after planting.

This period is characterized by vigorous growth, frequent occurrence of new shoots, shallow root distribution and weak stress resistance. At first, it had the ability to blossom and bear fruit, but the fruit setting rate was low. The management task in this period is to expand the growth range of roots, vigorously carry out vegetative growth of plants, produce a large number of robust and evenly distributed branches, and form a good crown skeleton, laying a good foundation for early fruiting and high yield.

soil management

Litchi is mostly planted on hills and slopes. These soils usually have low organic matter content, shallow soil layer and poor water and fertilizer conservation ability. If soil management is not paid attention to, the growth and development of litchi will be seriously affected.

1, soil management under canopy

Young litchi has few root systems, weak growth and mycorrhiza with a fungus. The growth of mycorrhiza needs a relatively ventilated soil environment. Therefore, the soil around the trunk under litchi canopy must be fertile and loose, rich in organic matter,

Conducive to the formation of mycorrhiza and the rapid development of root system. Therefore, the soil under the canopy should be loosened in time, more organic fertilizer should be applied, and the ground should be covered to prevent hardening.

2. Soil management outside the tree tray

In young litchi orchard, in order to increase economic income, short-term crops (such as vegetables and leguminous green manure) should be intercropped, combined with intercropping, fertilization, irrigation and loosening soil for many times. After harvesting, intercropping crops straw and green manure should be turned into the soil to increase organic matter and improve the soil. In the second and third years after planting, the soil around the tree tray must be improved in a planned way. Specifically, in autumn and winter, ditches with a depth of 50 cm and a width of 40 ~ 50 cm are dug outside the original planting hole, and the annual rate is 100 per plant.

About kg of weeds, leaves or green manure, add 1.5 kg of calcium superphosphate and cover the soil. Dig and press the green manure ditch, dig it on the east and west sides of the seedlings for the first time, dig it on the north and south sides of the seedlings for the second time, or dig a circle along the periphery of the crown.

3. Fertilizer and water management

Fertilization: Fertilization can be started one month after planting. Second, increase the amount of roots, promote shoots and strengthen shoots in three years. Master "one branch with two fertilizers" or "one branch with three fertilizers", that is, apply nitrogen-based quick-acting fertilizer when the top buds of branches germinate to promote the rapid growth of new shoots and long leaves; When the growth of new shoots basically stops and the leaf color changes from red to green, apply the second fertilizer to promote the new shoots to turn green quickly and the branches to thicken. After the new buds turn green, apply fertilizer for the third time to accelerate the aging of the new buds. In the first year of planting, fewer roots and smaller trees. Each plant uses 25g of compound fertilizer, about15g of urea, 0/0g of potassium chloride/kloc-0, 50g of calcium superphosphate. Young trees have few roots and weak fertilizer absorption ability, and foliar fertilizer can be sprayed 5-6 times a year.

Fertilizer and water management after planting 1 ~ 2-year-old young trees can promote the total leaf area of root groups and branches. The root system of young litchi after planting is few and weak, and its absorption is weak, so it is not suitable for fertilizing water. Fertilization is based on high quality, nitrogen combined with a small amount of phosphorus and potassium fertilizer, less but more precise, and the principle of diligent application and thin application. Young trees planted in that year can be applied with thin fertilizer and water 1 ~ 2 times a month. In the second and third years, it is mainly to increase the amount of roots, promote shoots and strengthen shoots. Quick-acting fertilizer, mainly nitrogen fertilizer, is applied once every time the top buds of branches sprout to promote the rapid growth of new shoots; When the leaves turn from red to green, apply the second fertilizer to promote the branches to turn green quickly, improve photosynthetic efficiency and accumulate nutrients. Fertilization can also be applied after the new shoots turn green, so as to accelerate the senescence of the new shoots and shorten the bamboo shoot development period.

Fertilization amount: in the first year, about 20g of urea can be applied to each plant, or about 30g of compound fertilizer can be applied, or 200-250g of urea or phosphorus and potassium fertilizer can be added to each load of rare human excrement, and 1-2kg can be applied to each plant every year. Starting from the second year, the amount of fertilization should be gradually increased, increasing by 50-60% on the basis of the previous year. Fertilization method, the first small tree had better dissolve the fertilizer in water and pour it into the tree tray. After the second year, it can be applied in shallow ditches on the soil outside the crown, and then covered with soil. In case of drought, irrigation should be done in time.

Leaves absorb fertilizer quickly and have high absorption rate. Therefore, after the new shoots turn green, we can fertilize outside the roots and spray 0.2% urea and 0.3 ~ 0.5% potassium dihydrogen phosphate on the leaves, which can promote the rapid maturity of the new shoots. However, special attention should be paid to the concentration used. If the concentration is too high, it will easily burn the leaves. The concentration should be reduced appropriately in case of high temperature and drought. Young litchi has weak root system and shallow distribution, which is easily affected by the change of topsoil moisture. In the case of high temperature and drought, if the soil moisture is too little, it will inhibit the germination and growth of branches and even plant death. Therefore, attention should be paid to irrigation and moisturizing in dry season. Attention should be paid to eliminating stagnant water in rainy season.

Drainage and irrigation: Water is an important part of litchi trees. Litchi young roots are few and shallow, which is greatly influenced by the change of topsoil moisture. Under the condition of dry soil and dry atmosphere, attention should be paid to watering and moisturizing. Water accumulation in planting holes should be prevented in rainy season, and submerged plants should be raised appropriately to facilitate normal growth.

Litchi mycorrhiza is aerobic, and the soil is loose and breathable, which is beneficial to the growth and development of roots. Young orchards generally loosen soil and weed 5-6 times a year. Summer and autumn are hot and humid, weeds grow rapidly, scarifying and weeding times are more, the ground temperature is lower in spring, the ground surface is dry in winter, rainfall is less, weeds grow slowly and farming times are less. The main contents of soil improvement in litchi orchard include deep ploughing to promote ripening, thickening soil layer and increasing organic matter. Its purpose is to improve soil physical and chemical properties, improve fertility and create good conditions for root growth. The soil improvement method is to open an annular ditch or two flat fertilization ditches around the original planting hole. Apply farm manure 8- 10 kg, calcium superphosphate 1 kg and compound fertilizer 0.5 kg to each ditch, and then cover the soil 25-30 cm above the ground.

4. Weeding and loosening the soil

Litchi mycorrhiza is aerobic, and weeding and loosening soil can help loosen soil and promote root development. Young trees can be combined with management in intercropping crops to weed and loosen soil. It is hot and rainy in summer and autumn, weeds grow fast, the soil is easy to harden, and weeding and loosening the soil are more frequent; Low temperature in winter and spring, drought, slow growth of weeds, less weeding and loosening the soil.

Young roots are shallow, so according to the range, the loose soil should be shallow, 8 ~ 10 cm, and the depth outside the rhizosphere can reach 15 cm.

Step 5 mix cropping

Litchi young orchard has a large space and ground, so making full use of the land for intercropping and interplanting is conducive to achieving the goal of raising the garden by garden, combining short-term cultivation with long-term cultivation and increasing income. Intercropping management can prevent soil erosion, inhibit weeds, prevent heat and moisture, promote microbial activities and accelerate the improvement of soil physical and chemical properties. Short-term dwarfing crops can be planted between young litchi rows, which can make full use of land, grow in a short time, increase income, inhibit weeds and prevent soil erosion. The stems and leaves of intercropping crops can be used as fertilizers and grass cover materials to improve the soil. However, it is forbidden to plant tall crops, climbing crops and crops with strong fertility, so as not to compete for nutrients, water and sunshine of litchi. Intercropping should strengthen fertilization and irrigation to improve soil fertility.

6. News reports

Covering soil in litchi orchard can reduce direct sunlight on the ground, reduce soil temperature in summer, keep warm in winter, prevent drought and keep moisture, reduce weed growth and increase soil organic matter. Weeds and crop straws are usually used to cover the' tree tray', and it is forbidden to stick the plastic film close to the trunk during operation to prevent termites and other hazards. Mulching can reduce evaporation, keep soil moist, adjust soil temperature, cool down in summer and keep warm in winter, which is beneficial to root growth; Can inhibit the growth of weeds and reduce weeding labor; After straw mulching decays, increase soil organic matter and improve soil.

(1) Dead plastic film: Generally, cover the tree tray with weeds, leaves and stems from intercropping crops (0/5cm away from the stem of litchi seedlings/kloc-0 to prevent termites), or cover it with black agricultural plastic film.

(2) Living plastic film: planting green manure between rows and cutting it into dead plastic film in dry season.

(2) Crown management

The purpose of young litchi crown management: according to the growth characteristics of litchi and local external environmental conditions, through various agricultural technical measures, control and promote the rapid expansion of the crown, increase the number of branches, grow strong branches, distribute the main branches and side branches evenly, have a firm skeleton structure, and have a short and dense crown, thus laying a good foundation for early fruiting, high and stable yield.

1, plastic surgery

Crown fruit is the main feature of litchi fruit, and the crown of high-yield type is mostly hemispherical or conical. From the year of planting, we should pay attention to cultivating hemispherical crown with short stem and 3 ~ 4 main branches. The height of trunk is 30 ~ 60 cm (short-branch variety is 30 cm, drooping-branch variety is 60 cm, dense planting garden is shorter and sparse planting garden is higher). When the height of the main pole is 30 ~ 60 cm, the top is picked (cut) to promote the division of 3 ~ 4 first-class branches (main branches) with uniform azimuth distribution; When the length of the first branch is 40 ~ 50 cm, the top is lifted (truncated) to form 2 ~ 3 secondary branches (secondary main branches), of which the front one is not truncated to extend outward, and the next two branches are lifted (truncated) to form a third branch (side branch); The main branch and many large lateral branches form the skeleton of the crown, so it is called the main branch. Then the third level branch is truncated to form the fourth level branch. Repeat this for 2 ~ 3 times to form a compact tree shape and increase the number of fruiting mother branches. If the branch angle between the main branch and the auxiliary branch is too small (less than 45 degrees), it can be adjusted by pulling rope or hanging stone. Through manual control, the shape of litchi tree becomes an open hemispherical crown.

The cultivation of backbone branches must start from the seedling stage, otherwise it will have a certain impact on the tree structure, the development and results of tree potential. In particular, varieties with sparse and long branches, such as March Red and Feizixiao, must be cultivated in tree form when they are young.

prune

Pruning young litchi trees requires that young litchi trees can cultivate a trunk with a height of 30-40 cm and 3-4 evenly distributed main branches, and the planting angle is appropriate, so the pruning targets are: cross branches, over-dense branches, weak branches and flowering spikes that are not allowed to bear fruit. Pruning can be done by pruning, coring, pulling, hanging and spreading. Branches that can be cut or not can be temporarily retained in order to effectively use nutrients to expand the crown.

In the past, young litchi trees were rarely pruned, so the crown was messy, the branches were too thin, the pests and diseases were serious, and the growth was weak. Prune once a year in winter, and cut off dense shade branches, cross branches, overlapping branches, pests and diseases branches, weak branches and dead branches, so that nutrients can be effectively utilized, the crown can be enlarged, and the crown can be ventilated and lighted, and pests and diseases can be reduced. After each new shoot matures, but before the next new shoot germinates, leave 20 ~ 30 cm of clustered branches and upright branches for short cutting.

The pruning of young trees should pay attention to the balance of the crown, and don't be high and low, or have different widths. If the strength of the backbone branches is quite different, it can restrain the strong and help the weak.

Pruning principle of young trees: light should not be heavy, less should not be much, and branches that can be cut or not should be kept temporarily. Pay attention to cutting more at the top and less at the inside to avoid cutting off the inner branches and drooping branches to form a shell-shaped crown with surface results. The pruning period should be carried out before the new branches sprout.

Second, the management of the result tree

Litchi has a long-term unstable fruiting phenomenon, which is common every other year or even several years. In addition to the influence of climatic conditions, the main reason is poor management.

For scientific management of litchi fruit trees, we should first pay attention to soil management, create a soil ecological environment conducive to the growth and development of litchi roots, make the roots develop vigorously and have strong absorption capacity, and ensure that the aboveground parts of fruit trees can blossom and bear fruit normally. Secondly, the crown management should be carried out reasonably, and the relationship between vegetative growth and reproductive growth should be adjusted according to the growth and development law of litchi, so that the branches of the fruiting tree will be strong and mature after wintering, and sufficient nutrients will be accumulated to ensure the formation of flower buds and fruits.

Third, fruit bagging protection.

In conditional orchards, when the litchi fruit is about five ripe (the base of the fruit begins to turn red), bagging the fruit ears can not only prevent insects and diseases, but also prevent bats; Moisturize and cool to prevent sun damage to fruits; Reduce evaporation, increase the temperature (in the bag) and promote fruit ripening. Autocratic fruit bags, transparent plastic film bags or translucent sulfuric acid paper bags can be used. The bag is cylindrical, about 30-40 cm long and 20-25 cm wide (the length and width depend on the length and size of the ear). Punch some holes with a diameter of 0.5 cm on it, put on your ears, tie them up on the top and open them slightly on the bottom. Spraying insect and disease prevention pesticides before bagging. When picking fruits, the ears and bags are picked together.

Save method:

Litchi that does not keep fresh has the characteristics of "one day changing color, two days changing fragrance, three days changing flavor, and four days without fragrance". The preservation of litchi is relatively difficult. According to legend, Yang Guifei, the ancestor of Ming Dynasty in Tang Dynasty, sent litchi from Lingnan to Chang 'an (Cai Xiang's Litchi Book and An Introduction to Nengzhai said that it was Luozhou (now Fuling, Chongqing), Song's Yi Bu lue thought that the litchi that Guifei ate came from a historical book (Leshan), and Lin Tong, a modern man, confirmed in Selected Works of Fuzhou Literature and History that Yang Guifei ate litchi from Luozhou. Du Mu has a poem "Crossing Huaqing Palace": "Looking back at Chang 'an, there are piles of embroidery, and the top of the mountain opens a thousand times. Riding a princess in the world of mortals, no one knows that it is litchi. " Du Fu wrote the poem "Sick Orange", saying, "Recalling the envoys of the South China Sea in the past, scrambling to offer lychees, and a hundred horses died in the valley, which is distressing to this day. "."The Legend of Yang Guifei said that Yang Guifei was hanged in Ant Hill, and it happened that litchi, a tribute from Guangzhou, arrived, and Xuanzong used it as a memorial to her.

The common modern preservation method is to choose varieties that are easy to preserve, and preserve them at low temperature and high humidity (2-4 degrees Celsius, 90%-95% humidity). The modified atmosphere is also used to reduce the proportion of oxygen to slow down oxidation; Or cooperate with drugs for sterilization and antisepsis. There are also some unscrupulous traders who spray litchi with dilute sulfuric acid to prevent corrosion, but it is harmful to human body.

Fresh litchi is listed in May every year, and July to August is the best time to make it. Fresh litchi just picked can often be bought in cities near the place of origin. As for places far from the place of origin, you can only buy frozen ones. Canned lychee is also very popular. Generally, the shell and core are removed and soaked in light sugar water. The taste is far from freshness, and it is often used as a cold drink or dessert. Agricultural control

1. Re-apply shoot tip fertilizer and appropriate flower protection fertilizer to enhance tree vigor and improve tree stress resistance.

2. Pick the fruit in time, do a good job of clearing the garden after picking the fruit in winter, prune it in time, restrain the winter shoots, and reduce the source of overwintering pests and diseases.

Chemical control

1, spring shoot stage (bud stage) and flowering stage, and do a good job in the prevention and control of litchi stinkbug and late blight.

① To control litchi stinkbug, gall midge and leaf gall midge, spray with 4.5% Luff EC 1500 times solution and 24% Wanling aqueous solution 1000 times solution, or choose 20% Mirex EC 1500-2000 times solution and 4800 times solution.

② If late blight and anthracnose often occur in rainy days before flowering, 64% Tian Liang WP can be used to control late blight and 70% Red Sun WP600 times solution can be used to control anthracnose.

2. Fruit-bearing period: Do a good job in the prevention and control of litchi blight and litchi stem borer, and also deal with other pests such as litchi stinkbug. During the control period, the emergence rate of litchi stem borer is about 30%, which is sprayed for the first time and repeated after 5-7 days 1 time. 4.5% Lvfu EC 1000 times solution (or 4.5% Lvfu EW 1500 times solution), or 480g/L Nuo Nuo EC 500-800 times solution and 30% Nongerwang EC 500-800 times solution can be used alternately or mixed for spraying.

3. Cultivate strong autumn buds. It can be sprayed for the first time when the autumn shoots just come out about 5 cm, and then controlled in 10- 15 days. 4.5% Ruff EC 1000 times (or 4.5% Ruff EW 1500 times), 500-800 times of 30% Nongerwang EC, 1000 times of 24% wanling aqueous solution, or 6550 times of 480g/L can be used.

4. Do a good job of protecting flowers and fruits. Spraying 0.0 1% tianfengsu EC (diluted 3000-4000 times) in bud stage, young fruit stage and fruit development stage can promote flower bud differentiation, and achieve the functions of flower protection, fruit protection and fruit quality improvement.

Fruit drop from one month after flowering to before harvest is mainly caused by insect pests.

Litchi cocoa moth

Kill 1000 times with 50% phenylbutylamine alcohol emulsion or 50% phenylbutylamine alcohol emulsion, and apply 1 time every 10 day for 3-4 times continuously about 20 days after flowering, but it must be stopped before 10 day. Litchi gum

Use 35% triamcinolone acetonide emulsion 1000 times, or 75% wettable sulfur powder 300 times, start to apply the medicine when tender shoots are pulled out, and then apply the medicine after 7- 10 days.

Lychee mite

When symptoms appear in early spring, 40.64% Fu Bao water suspension powder, 33% triamcinolone acetonide emulsion or 75% moderately wet sulfur powder are sprayed for prevention and treatment. At the same time, cut off diseased branches and burn them to reduce the source of insects in the coming year. Litchi dew blight

1, remove the diseased fruit, and when pruning, cut off the drooping branches within 60 cm near the ground to avoid the bacteria in the soil splashing on the trees with the rain. For orchards with serious diseases, plastic sheets or straw can be used to cover the ground.

2. Before the rain comes, the fruit trees can be fully sprayed with 33.5% fast-dissolving suspension powder mixed spreading agent to prevent the initial source of infection.