A detailed guide to mango cultivation techniques: master these methods to grow mangoes well

SummarySite: choose a plain or hilly area that faces the sun, has deep soil, drains well and has irrigation available. Orchard planning: arrange the drainage and irrigation system, the road system and the orchard's supporting facilities according to the terrain and landforms. Spacing: 40 plants per mu, 5*3.3m (row spacing * plant spacing) is more suitable. Fertilization: light fertilizer applied frequently, 6-8 times a year, mainly quick-acting liquid fertilizer. Drainage and irrigation: drain promptly on rainy days to prevent root rot. Pruning: carry out appropriate shaping and pruning after planting.

Through many years of practical experience with mango seedling planting methods, whether in seedling propagation techniques or sapling planting techniques, a relatively mature planting process has been developed. Below we will take a detailed look.

I. Mango seedling propagation techniques

In the past, mango seedling raising mostly used the seedling propagation method (obtaining seedlings directly through seeds). The advantage of this method is that it is relatively simple, but the variability is rather large, and its fruiting period is late (generally it takes 5 to 7 years before it enters the flowering and fruit-setting period). This method is currently mainly used for the propagation of landscaping seedlings, and is generally no longer used in production.

1. Rootstock cultivation

(1) Site selection

The nursery site should be far from mango orchards, and there should be no old mango trees around. The benefit of doing this is that it can reduce the spread of pests and diseases and can better cultivate seedlings free of pests and diseases. At the same time, the nursery site is required to have convenient transportation and convenient drainage and irrigation.

The nursery site should also be chosen as gently sloping land with conditions such as being sheltered from the wind and facing the sun, facing south with its back to the north, and having sufficient sunlight. The groundwater level is best below 1 m. Because low-lying land easily collects cold air and forms frost, and at the same time drainage is difficult, it is very prone to waterlogging damage, so it is not recommended.

The nursery site is best suited to sandy loam with a pH of 5.5 to 6.5. Because sandy soil has poor water retention, mango seedlings are very easily affected by drought and sunburn, and later growth will be relatively poor. The disadvantage of clayey soil is poor air permeability and drainage, the soil easily becomes compacted, causing poor root growth, and when seedlings are lifted the roots are damaged rather seriously, so the survival rate after planting is correspondingly lower.

Mango nurseries are not suitable for long-term continuous cropping, otherwise the soil fertility of the nursery will decline noticeably, pests and diseases will also become more serious, and this is unfavorable to plant growth.

(2) Seed treatment

Mango seeds do not store well, and even more so must not be dried in the sun. After mature mango seeds are taken out of the fruit, they should be sown immediately, so as to ensure a relatively good germination rate. The longer mango seeds are left after being taken out of the fruit, the lower their germination rate will be. If long-distance transport is needed, it is recommended to use fresh fruit for storage and transport.

Mango seeds have a relatively thick seed coat, germination is relatively difficult, and it generally also appears uneven, so shelling treatment is needed, sowing the kernel, so that germination is easier and more uniform. After the mango seed kernel is taken out, it can be placed on a sand bed to germinate, and after sprouting it can be moved into the seedbed. The shelled kernel can also be sown directly in the field seedbed at a spacing of 15*20cm.

① Sand bed germination

The sand bed should be chosen in a relatively shady place, with a sand thickness of preferably 10 to 12cm. For the convenience of later management, the bed surface width is best around 80 to 100cm. A shade net can also be added over the seedbed in the field nursery, for the purpose of preventing direct sunlight and rainstorm washing, which is more conducive to the normal emergence and establishment of seedlings.

② Seed disinfection

Before sowing, mango seeds are recommended to be treated with a 50% carbendazim wettable powder 800 to 1000 times solution before sowing. When sowing, it is best to place the kernels flat on the sand bed, laying them out flat one after another, then cover them with fine sand, with a recommended thickness of about 1cm above the kernels, then water them thoroughly, and finally cover the bed surface with plastic film, but be careful to keep the soil moist.

③ Bed separation and transplanting

Generally after about one week of germination the seeds begin to push out of the soil surface, and after about 2 weeks the seedlings have basically all emerged. The seedlings are initially purplish red, and generally they can be separated and transplanted when their leaves have not yet unfolded; at this time the survival rate of transplanted seedlings is generally also the highest. The recommended transplanting spacing is 15*20cm; according to this spacing, generally about 8000*10000 seedlings can be raised per mu. When transplanting, it is best to take out the young seedlings together with the kernel and plant them into the seedbed, and seeds with multiple embryos must be carefully separated. In order to facilitate later management and improve the uniformity of seedling growth, when transplanting, seedlings of consistent growth must be selected and transplanted into the same seedbed, while weak and small seedlings are placed in another seedbed for cultivation. When transplanting, the root system must be spread out; if the main root is too long, the main root can be appropriately shortened to promote lateral roots; as for covering with soil, it is enough to cover past the root crown of the seedling.

In order to facilitate later management, and to help seedlings leave the nursery and improve the survival rate after planting, it is recommended to use nutrient bags for seedling raising. The specific method is: choose black plastic bags with a diameter of 20 to 24cm and a height of about 25cm, fill them with nutrient soil (formula: 2/3 paddy field soil mixed with 1/3 decomposed farmyard manure), then move the seedlings into the raising bags; the management method is basically the same as seedbed management.

④ Nursery management

(1) Shading and sun protection. The transplanting season is exactly the high-temperature and strong-sun season, so it is best to use a 50%-60% shade net as a shade shed to prevent sunscald. After the seedlings grow steadily for 1 month, the shade net can then be removed.

(2) Fertilizer and water management. After transplanting, the soil must be kept moist. When dry weather occurs, water must be sprinkled 1 to 2 times a day until the seedlings resume growth, and then the number of waterings should be gradually reduced. When the plants begin to put out new shoots, thin manure water or a 1% urea water solution can be applied. For each flush of shoots, generally 2 fertilizations are needed to promote rapid seedling growth. In order to prevent soil compaction, loosen the soil and weed frequently, and cover the bed surface with organic matter (rice straw, mountain grass or decomposed miscellaneous manure, etc.).

(3) Pest and disease control. At the seedling stage, the main pest is the mango shoot borer damaging new shoots. From shoot sprouting to maturity, spray insecticides such as trichlorfon or omethoate every 7 to 10 days. For disease prevention, Bordeaux mixture or other fungicides can be sprayed.

(4) Seedling grafting. When the rootstock has been cultivated to a diameter (that is, when the height above ground reaches about 15cm) of 1 to 1.2cm, grafting can be carried out. Temperature and humidity are among the main factors determining grafting survival. Generally when the temperature is below 20°C, seedling vigor weakens. The grafting survival rate declines as the temperature drops, and in severe cases they cannot survive. Excessive humidity, however, easily causes disease, causing scion death or rootstock dieback, seriously affecting the seedling formation rate. Grafting can be carried out when the sap begins to flow and the bark is easy to peel. If in the Guangzhou area, then May to September is the most suitable season. There are many grafting methods, mainly selected according to the size of the rootstock; smaller rootstocks can use small-bud cut grafting or cleft grafting, while slightly thicker rootstocks can use patch budding.

Selection of scions: generally, on better mother trees, select disease-free and pest-free terminal buds or lateral buds with plump and prominent buds from one-year-old, mature branches on the sunny side as scions. This grafting method has a high survival rate and produces robust seedlings. After collecting the scions, cut off the leaves, then put them in plastic film bags to keep them moist, and avoid sunlight. It is recommended to collect and graft immediately; if they are to be kept for later use, they must be placed in a cool place and stored in wet sand. If long-distance transport is needed, wrap them well in wet paper, then put them in plastic film bags to keep them moist.

Grafting methods:

① Patch budding method

The advantages of this method are good healing, high scion utilization rate, and convenience for patching, so it is widely used by many mango growers. The specific grafting method is: on the trunk about 30cm above the ground of the rootstock, choose a flat and smooth part, make one horizontal cut, then make one vertical cut on the left and right along the direction, with depth reaching the cambium. After opening the position, peel open and remove the bark from above, forming a rectangular budding position about 0.6cm wide and 1.5 to 2cm long. The size of the budding position depends on the size of the seedling. Then cut a bud piece slightly shorter and smaller than the budding position (the method is the same as for the rootstock), then lift the bark of the budding position, place the bud piece in the middle, but be sure not to place the bud piece upside down. After it is completely joined, use plastic film to wrap and seal the budding position from top to bottom. After it survives, cut off the rootstock above the grafting position in stages. This method can also be used for top grafting to change varieties.

② Cleft grafting method

Some growers also call it the split grafting method. This method can be used for rootstocks of any thickness. Generally, cut off the upper part of the rootstock at 25 to 30cm above the ground, then split open a joint 1.5 to 2cm long in the middle, then cut the scion into a wedge shape with the same cut surface on both sides and insert it into the split of the rootstock. The cambium of the scion and rootstock must be aligned (at least one side aligned), and finally bind it tightly with plastic film. The characteristics of this method are firm healing and a high survival rate.

③ Cut grafting method

It can be carried out with rootstocks of any thickness. When grafting, first cut off the upper part of the rootstock, then cut vertically down between the xylem and bark of the cut surface, about 1.5cm long; the scion can be single-bud or multi-bud. Then cut one side of its lower end into a cut surface slightly longer than the rootstock cut surface, and cut the lower end on the opposite side of the cut surface into a 45° angle, then press the two cut surfaces of rootstock and scion tightly together, aligning the cambium of both. Note: if there is a difference in size between rootstock and scion, one side of the cambium must still be aligned. Finally wrap with plastic film. Compared with the previous two methods, this method is simpler and easier to do, and the survival rate is also very high.

④ Whip grafting method

First cut off the upper part of the rootstock (30cm above the ground), then cut a corresponding slant on the base of the scion and the top of the rootstock respectively. The scion and rootstock must be the same size; align the joint and bind tightly. Because whip grafting is a whole-branch butt joint, healing between the xylem of the two is difficult. Therefore the dieback rate is high, and wind resistance is poor. At present this grafting method has basically been eliminated.

⑤ Approach grafting method

The characteristic of this method is that the scion does not separate from the mother plant before surviving. Generally, choose a robust and smooth branch, cut a cut surface about 5cm long reaching the xylem, cut a corresponding cut surface on the rootstock as well, then align the bark of the two and bind tightly with plastic film. After the two sides have fully healed, cut off the scion below the joint, and cut off the part of the rootstock above the joint, forming a new plant. Because the scion has not detached from the mother plant before surviving, this method makes survival relatively easy, but when the mother tree is tall, trestles must be set up, which is rather laborious, and more scions are needed.

⑥ Air layering

Air layering is also called marcotting. Generally, choose branches of excellent varieties that are more than two years old, peel off a ring of bark about 5cm wide, scrape the cambium clean, and wrap the girdled area with rooting material that has strong moisture retention and is rich in nutrients, to promote new roots at the lower end of the branch, making it a new plant. The advantages of air layering are a high survival rate, fast seedling formation, and easy mastery of the technique, but the propagation coefficient is low, and it is more suitable for branches that are too dense between plants or need pruning.

(5) Management of grafted seedlings

① Untying and patching

Generally, special plastic film tape for grafting is used, and after grafting there is no need to untie it; the bud can generally pierce out on its own. If ordinary plastic tape is commonly used for binding, then when the bud eye is plump and prominent, the plastic tape at the bud eye must be removed to let it extend naturally, and after the bud grows into a new shoot, then untie it. When untying, use a knife to gently cut the plastic tape on the back of the joint; do not get close to the joint and do not cut into the bark. Note: plants that fail to survive grafting must be patched in time.

② Cutting the rootstock

For plants with patch budding that have successfully grafted, cut the rootstock 4 to 5cm above the budding position to prompt the grafted bud to sprout.

③ Removing sprouts

A large number of leaf sprout buds are easily put out from the base of the rootstock or above the cut, and must be removed in time, so that the sprout buds do not compete with the grafted bud for nutrients and affect scion sprouting.

④ Fertilizer and water management

After budding, keep the soil moist and water appropriately. After the grafted bud sprouts, apply a light application of quick-acting chemical fertilizer once, and thereafter apply fertilizer once for each flush of shoots, and pay attention to preventing stem borers from damaging new shoots.

⑤ Seedlings leaving the nursery

The quality of the work of leaving the nursery directly affects survival after planting and the growth of young trees. Seedlings carrying pests and diseases, or whose new shoots are not yet mature, should be temporarily held back from leaving the nursery.

Time of leaving the nursery: the time of leaving the nursery is determined by the planting time. Mango planting has two periods, namely spring planting and autumn planting, so seedlings leaving the nursery are also divided into the two planting periods of spring and autumn. Spring release from the nursery is from early March to early May. At this time, as seedlings leave the nursery, the temperature gradually rises and there is plenty of rain, which can save the labor of watering and also suits the requirements of seedling growth, so transplanting is mostly carried out in spring. Autumn planting (August to September), because the weather is relatively dry and the sun is intense, has a survival rate slightly lower than spring. It should be chosen to plant after typhoon rain.

Specifications for seedlings leaving the nursery: seedlings should conform to the specifications for leaving the nursery. Seedlings leaving the nursery should have the following 3 points: robust growth, reaching a certain height and thickness; the graft union heals well; no serious pests and diseases, especially quarantine pests and diseases.

Lifting seedlings: there are two methods of lifting seedlings, namely: lifting seedlings with soil. Before lifting seedlings, the nursery soil must be fully moistened to reduce root damage. Lifting seedlings should be carried out on sunny days. The mud ball should be 15cm wide and 20cm high. After lifting, immediately bind it well with rice straw or plastic film bags, then cut off 1/3 of the leaves and the new shoots that have not yet turned green; lifting seedlings without soil. For lifting seedlings without soil, water thoroughly before lifting, to make it easier to retain more fibrous roots when lifting. After lifting, 2/3 of the leaves and new shoots should be cut off, then the roots should be dipped in thin mud slurry to protect the roots, and the root part should be wrapped with plastic film to keep it moist. According to the convenience of the work, tie several plants into a bundle. For long-distance transport, the stacking must not be too high or too dense, and it must be shaded to prevent heating. This kind of seedling is only suitable for spring transplanting.

Seedlings raised in nutrient bags are not restricted by the propagation season, are convenient to plant, and have a high survival rate.

II. Orchard establishment and planting

1. Selection of orchard site

Although mango is a fruit tree species that grows quickly, bears early and has strong adaptability, and its requirements for soil are not very strict, it still cannot grow well just anywhere. It needs certain external conditions to bring into play its characteristics of fast growth, early bearing, high yield and good quality.

Since mango growth requires sufficient sunlight and prefers a warm environment while avoiding frost and low temperatures, orchard establishment should choose plains or hilly land that faces the sun, has deep soil, drains conveniently and has irrigation conditions. At the same time, for the convenience of future management and to reduce costs, the transportation conditions and facilities of the orchard site must also be considered.

2. Orchard planning

Do a good job in the basic infrastructure construction of the land. According to the terrain and landforms, arrange the drainage and irrigation system, the road system and the orchard's supporting facilities (such as tool and fertilizer warehouses, field fertilizer composting pits, medicine storage and preparation rooms, dormitories, fruit handling workshops and warehouses, etc.), divide the planting plots well, and also set up shelterbelts at wind gaps. If it is hilly sloping land, then according to different slopes, carry out contour hole setting or build terraces, so as to achieve the purpose of conserving water, fertilizer and soil.

3. Preparation of planting holes

The specifications of planting holes can be treated separately according to different soil qualities. For soil with deep soil layers and loose texture, the planting holes can be dug shallowly, and for lower-lying ground, even mound-style planting can be used; if planting on clayey soil or soil with hard gravel in the shallow layer, then holes must be dug for planting, generally with a hole size of 100cm*100cm*60 to 80cm (length*width*depth). When backfilling soil, first place weeds at the bottom of the hole, and mix the topsoil and subsoil separately with an equal amount of decomposed organic fertilizer and fill them back. Each planting hole needs fertilizer of 25 to 30 kg of organic fertilizer, 1 kg of lime, and 1 to 1.5 kg of phosphate fertilizer. The backfilled soil surface should be 20 to 30cm higher than the ground. Planting can be carried out only after the organic fertilizer in the planting hole has decomposed and the soil has settled and stabilized.

4. Planting spacing

Mango is a fast-growing, tall arbor fruit tree. Its branches grow rapidly and the canopy forms very quickly. For a four-year-old mango after planting, the canopy coverage has already reached 6.5 sq m, and at 50 plants per mu, by six years old it has basically fully closed canopy. Therefore, when establishing an orchard, the planting spacing should be considered from the perspective of economic cultivation. Planting too sparsely will affect the early yield per unit area and waste space; planting too densely will cause early canopy closure, which is not conducive to ventilation and light penetration, easily breeds pests and diseases, affects yield and quality, and increases management difficulties. Therefore, in order to achieve both high yield and good quality of the fruit and convenient management, the planting spacing should be established on the basis of economic cultivation. Different planting spacings are used according to different varieties, and based on 40 plants per mu, that is, 5*3.3m (row spacing * plant spacing) is more suitable.

5. Layout of varieties

Variety selection is directly related to the success or failure of commercial mango production. When selecting, not only must the quality of the fruit and the degree of market suitability be considered, but more importantly, whether the selected variety can suit the ecological conditions of the region and whether it can steadily obtain yield after planting. At the same time, the combination of early-, mid- and late-maturing varieties must also be considered. At present, many mango varieties have been introduced in various places, but most varieties cannot adapt to the low-temperature and rainy weather in South China during the flowering period, resulting in low and unstable yields and a lack of value for economic cultivation. Through practice, the varieties currently more suitable for cultivation in the Guangzhou area include: Zihua Mango, Guixiang Mango, Yuexi No. 1 Mango, Hongmang No. 6, and the newly introduced Jinhuang Mango, etc. These varieties have the characteristics of a late flowering period and a moderate ratio of bisexual flowers, making it easier to obtain stable yields.

6. Planting methods

To improve the survival rate of planting, in addition to the quality of the seedlings themselves (including the quality of lifting the seedlings), timely planting and attention to planting methods are also needed. Generally, the mango planting period is preferably spring. When the cold wave has passed, the temperature has clearly risen, the air humidity is high, and the fruit seedlings have not yet put out new buds, planting then gives a high survival rate (planting from March to May is most suitable). Autumn planting has high temperatures and easily puts out shoots, but it is relatively dry, the sunlight is strong, and transpiration is large, so planting should be chosen when there is autumn rain, so as to improve the survival rate.

Transplanted mango seedlings come in two kinds: those with soil and those bare-rooted. Seedlings with soil survive easily and resume growth relatively quickly; for bare-rooted seedlings, if attention is paid to the quality of lifting, the roots are dipped in mud slurry, the roots are kept moist during transport, and watering management is strengthened after planting, the survival rate will still be very high. No matter which kind of seedling, when planting, 2/3 of each leaf should be cut off to reduce water transpiration, maintain the physiological balance between the aboveground and underground parts, and help survival. When planting, place the seedling in the middle of the planting hole, being careful not to break the mud ball of soil-grown seedlings, and fill fine soil around the mud ball, with the depth of soil covering preferably up to the root crown. After planting, water thoroughly to set the roots, and thereafter determine the number of waterings according to weather conditions. In sunny weather, water once every 2 to 3 days, keeping the soil moist, until the plant resumes normal growth.

III. Management of young trees

1. Fertilization, drainage and irrigation

The root system of young trees is not yet well developed, so fertilization should be in small amounts and many times, which is the so-called “light fertilizer applied frequently”, to reduce waste of fertilizer and loss of nutrients. Fertilizer can be applied 6 to 8 times a year, mainly quick-acting liquid fertilizer. In places affected by low temperatures, stop fertilizing from November, so as not to promote tender shoots and affect overwintering. Summer shoots occur many times, which is conducive to canopy expansion. Each young tree should be applied each year with 73 grams of pure nitrogen, 18 grams of phosphorus, and 68 grams of potassium. It can be seen that to promote the vegetative growth of young trees, nitrogen fertilizer should account for a larger proportion, but the application of other major elements should not be neglected either, so that young fruit trees can grow normally. The specific method is: after planting and survival, young trees can be fertilized. Apply fertilizer once every 30 to 40 days, mainly water fertilizer. Each plant each time is applied with water fertilizer made by soaking 50 grams of raw bran, 40 grams of potassium fertilizer, or 10 kg of manure water plus 20 grams of urea diluted into one manure bucket and directly sprinkled around the outer edge of the canopy. If dry fertilizer is used, then dig strip trenches or ring trenches 20cm away from the trunk, evenly spread the fertilizer in the trenches, cover with soil and then water thoroughly.

The tree holes of young trees should be kept moist. Cover the tree base with mountain grass or rice straw to reduce evaporation of soil moisture and avoid surface soil compaction. At the same time, pay attention to draining water promptly on rainy days to prevent water accumulation and root rot.

Protecting seedlings and shaping: the root system of young trees is not yet stable and is easily affected by adverse environments, especially heavy rain and strong wind. Before wind and rain, support work should be done well; after heavy rain, promptly straighten plants that have tilted or fallen, and at the same time avoid large livestock entering the orchard and causing damage.

Mango trees grow quickly and develop rapidly, with many branches and dense leaves, and easily form a closed canopy, which is not conducive to economic cultivation. Therefore, after planting and survival, appropriate shaping and pruning should be carried out. Its purpose is to make the branch distribution reasonable, make the tree body well lit, and form a tree structure with early bearing, high yield and stable yield, which is beneficial both to the current vegetative growth and to future flowering and fruiting. The specific method of trunk training and shaping for young trees is: in the year of planting, for young trees with few branches, wait until the trunk grows to 60 to 70cm high, then pinch the tip to promote branching, so as to promote canopy expansion. After pinching, multiple new shoots will soon grow on the trunk. According to the principle of “remove the strong and the weak, keep the middle”, keep 3 evenly distributed new shoots as main branches. When the main branches grow to 30 to 40cm, cut them again, each keeping 2 to 3 new shoots as first-level branches. Carry this out several times to speed up canopy formation. In the first one or two years after mango planting, the shaping work of the canopy should be basically completed. When it is about to bear fruit, the last-level shoots can keep 3 evenly distributed mature branches as fruit-bearing mother branches. Young trees are generally only lightly pruned, mainly to promote rapid canopy formation; it is enough to remove diseased and pest-damaged branches and drooping branches that touch the ground.

IV. Management of fruiting trees

1. Soil management

The root system of mango belongs to mycorrhizae, living symbiotically with root fungi and promoting each other, and the root fungi need more organic matter and a well-aerated soil environment to grow well. Therefore, increasing soil organic matter and improving soil properties have become a very key technical link in mango cultivation. Under the high-temperature and humid climate conditions of the south, organic matter decomposes quickly, and soil organic matter consumption is also large. Therefore, in addition to increasing the application of farmyard manure and miscellaneous manure to increase the content of soil organic matter, the use of sod culture has become an important soil management technical measure for perennial fruit tree cultivation in the south, and is increasingly commonly accepted by people, because it is not only conducive to improving the ecological conditions of the planting site, but also plays a positive role in conserving soil, water and fertilizer and increasing soil organic matter. The specific method is: do not carry out hoeing of grass; consciously retain low-growing weeds as vegetation, but tall weeds that affect the plant's light exposure, climbing weeds, and weeds that hinder cultivation must still be removed. In winter, a comprehensive orchard cleanup must also be carried out, removing weeds to reduce sources of insects and disease and places for pests and diseases to overwinter.

2. Scientific fertilization

Research data from India show that for every 1000 kg of mango harvested, 6 kg of pure nitrogen, 3 kg of phosphorus, 10 kg of potassium, 5.9 kg of calcium, and 3.6 kg of magnesium are consumed. This is only the part consumed by fruiting; if the needs of its growth and development are also to be met, then it is far more than this amount. The consumption of nitrogen, potassium and calcium by fruiting trees is relatively high. Generally speaking, when fruiting trees are rationally fertilized, the ratio of nitrogen, phosphorus, potassium and calcium should be 6:4:9:6 or 6:3:10:6. In production practice, in addition to the above 4 major elements, mango is also sensitive to trace elements such as manganese, boron, magnesium and zinc. If the supply of these elements in the soil is lacking, various physiological diseases often appear. The fertilization periods for mango fruiting trees should be based on physiological phenology.

(1) Flower-strengthening fertilizer

Apply before flower bud appearance in late February to early March. The purpose of this fertilizer is to raise the nutritional level of the tree, promote flower panicle development, enhance cold resistance, and increase the fruit-setting rate. The fertilizer is mainly quick-acting nitrogen fertilizer, applied together with phosphorus and potassium fertilizer, with the amount accounting for about 30% of the annual fertilization amount.

(2) Fruit-strengthening fertilizer

Apply during the young fruit stage after flowering. According to conditions such as tree vigor and the amount of fruit set, mainly potassium fertilizer and calcium fertilizer, appropriately combined with nitrogen fertilizer, with the fertilization amount accounting for 5% to 10% of the year. It can also be combined with pesticide spraying for disease prevention by adding 0.3% potassium dihydrogen phosphate as a foliar topdressing; when necessary, trace elements such as boron and magnesium can also be supplemented.

(3) Post-harvest (pre-harvest) fertilizer

Its main role is to enable the tree vigor to recover quickly after harvest and promote robust autumn shoots and early winter shoots as fruit-bearing mother branches for the next year. The fertilization time depends on the mango variety and the fertilizer type. Early-maturing varieties can be applied with quick-acting fertilizer promptly after harvest, while for late-maturing varieties, whether quick-acting fertilizer or slow-acting organic fertilizer, it should be applied before harvest. It is required to finish application before late August, to ensure that the first autumn shoots can be put out in early to mid-September. This fertilizer is mainly organic fertilizer, applied together with potassium fertilizer, phosphate fertilizer and some quick-acting nitrogen fertilizer, with the fertilization amount accounting for more than 50% of the year.

(4) Overwintering fertilizer

Apply in mid-to-late November, to prompt early winter shoots to mature quickly, which is conducive to flower bud differentiation. At the same time, it increases the concentration of tree sap, enhances cold resistance, and can also partly provide nutrient supply for the flowering period of the next year. This fertilizer is mainly slow-acting organic fertilizer. It can also be combined with winter pond clearing and the application of pond mud or other foreign soil, with the fertilization amount accounting for 10% of the year.

3. Rational drainage and irrigation

Mango has different water requirements at each growth and development stage. The key periods when water is needed are the fruit enlargement period and the autumn shoot sprouting period. During the young fruit enlargement period, in ordinary years the rainfall in South China is relatively sufficient, so irrigation is not needed. However, in the middle stage of fruit development, cracking and fruit drop are often caused by high temperatures and sudden rain. During this period, attention should be paid to appropriate irrigation and keeping it often moist, to prevent yield losses caused by overly drastic changes in soil dryness and wetness. From the late stage of fruit development to before harvest, a relatively dry environment is needed, which is conducive to improving the quality and commercial value of the fruit. In late summer and early autumn in South China, dry weather with little rain often occurs, with high temperatures, large transpiration, and low humidity in both soil and air. At this time, it is exactly the key period for post-harvest pruning to promote shoots, so sufficient water should be kept in the soil to promote autumn bud sprouting and meet the needs of neat autumn shoot emergence and robust growth and development. Therefore irrigation should be carried out to keep the soil moist. When the last shoots begin to mature, irrigation should be stopped. At this time, moderate drought can make the branches stop growing in time, accumulate photosynthetic nutrients, and increase cell sap concentration, which is conducive to flower bud differentiation. However, at this time excessive drought will prompt early flowering, poor flower quality, a low ratio of bisexual flowers, and poor fruit setting. Therefore, in winter and spring, if drought occurs, an appropriate amount of irrigation is still needed; a light watering can be given once every 15 to 20 days, so that the soil around the tree is slightly moist.

4. Moderate pruning

Mango is a fruit tree that tolerates pruning relatively well. The pruning method and intensity for mango fruiting trees should differ according to variety, tree age, tree vigor, planting density, site conditions and management level. For example, through pruning, the loose tree shape of Guixiang Mango can be forced to become more compact, and the dense branches of Zihua Mango can be made to extend reasonably. Mango tree pruning can be divided by time into spring pruning and autumn pruning.

(1) Spring pruning

In order to regulate the balance between vegetative growth and reproductive growth, which is conducive to balanced production and improving fruit quality, the number of flower panicles should be controlled. Thin flowers during the period from panicle emergence to flowering, removing excessive flower panicles. Generally, having flower panicles emerge on 70% of the last-level shoots is sufficient; the remaining 30% should be made to put out spring shoots, ensuring a certain amount of vegetative growth. If the flower panicle is too long, part of the small flower branches should be removed, and retaining 1/2 to 2/3 of the flowers is enough. If too many fruits set in the young fruit stage, part of the small fruits should be removed early, leaving only 5 to 6 well-developed small fruits per panicle for observation, and deciding later whether to keep or remove them when they are slightly larger. At the same time, empty flower branches and diseased and weak branches should be cut off in time, to prevent the fruit from colliding and rubbing against them and affecting the fruit's appearance.

Young fruiting trees with relatively few fruits often put out summer shoots, and competition for nutrients will cause a large amount of fruit drop, seriously affecting the already small fruit load. Therefore, to ensure normal fruit development, shoots should be removed when summer shoots sprout 3 to 5cm.

(2) Autumn pruning

Autumn pruning of mango is generally carried out after harvest, so it is also called post-harvest pruning. This pruning has the effect of promoting the emergence of autumn shoots. After harvest, at least two emergences of autumn shoots should be cultivated, and the last shoots should not emerge later than early November. Therefore, autumn pruning should strive to be completed by late August to early September.

The objects of pruning are dense branches, closed-canopy branches, redundant branches, disordered branches, drooping branches, overlapping branches, crossing branches, diseased and pest-damaged branches, etc. The pruning method is to first remove overly dense and excessive main branches, adjust the position and number of skeletal branches, then cut off the above-mentioned target branches, and according to different varieties and requirements for tree shape, retract and shorten long branches, and cut back the residual branches that have borne fruit on the outer periphery at the dense node below. The principles of mango pruning are: “shape according to the tree, suppress the top and promote the bottom, loosen and balance, heavy on top and light below”. Autumn pruning of fruiting trees should be combined with heavy fertilizer application before and after pruning, to ensure the supply of inorganic nutrients needed for vegetative growth, quickly restore tree vigor and physiological functions, accumulate nutrients for flower bud differentiation, and lay the foundation for next year's production. At the same time, during pruning, except when tree renewal is needed, pruning should generally not be too heavy.

5. Flower control and fruit thinning

Appropriate measures should be taken to control the flowering period and delay flowering, so as to avoid the influence of adverse climate. For some varieties with the habit of flowering multiple times, the method of removing inflorescences can be used. Generally, removing terminal inflorescences causes the lateral buds to redifferentiate flower buds, which can delay the flowering period by about 1 month. The method is to remove the early-emerged flower panicles from the base, letting them re-emerge flower panicles from lateral positions at the base. If the primary flower panicle emerges too early, it can also be cut back from several bud positions below the flower panicle on the base branch, to promote lateral buds to put out flower buds again. Bud removal should be done in time before the flower buds elongate to 7cm; otherwise nutrients will be consumed excessively, the flower quality of the regenerated panicles will weaken, and fruit setting and fruit quality will be affected. If after removing the flower panicles the temperature is high and the panicles emerge quickly, the newly emerged panicles can be removed again; generally flower removal can be carried out 2 to 3 times in succession. For flower panicles emerging in mid-February and later, the small flowers can open in late March and early to mid-April, when the temperature is most suitable for mango pollination and fruit setting. Therefore, after mid-February, bud removal and flower control should be stopped.

For plants that do not flower due to excessive vegetative growth or other reasons, physical or chemical measures can be used to prompt the branches to stop growing in time, accumulate sufficient photosynthetic nutrients, and promote flower bud differentiation and flowering.

① In the dry season of late November, deeply turn the soil and cut off part of the lateral roots. Sun them until the leaf color turns yellow-green, then cover with soil combined with applying organic fertilizer. This work must be completed from Great Cold to before the Beginning of Spring. The ring-girdling technique can also be used (around Lesser Cold, ring-girdle the first-level branches with No. 16 iron wire, twist tightly with pliers until it goes deep under the bark, and untie after flowering).

② Use plant growth regulators. Plant growth regulators are mainly used to control vegetative growth, promote flower bud differentiation, flowering, flower promotion, fruit retention, and overcome alternate bearing, etc. The same chemical, due to different application periods and concentrations, shows different physiological responses. Before using a chemical, its properties, concentration and timing of use must be understood before it can be applied. At present, a widely used low-toxicity and clearly effective plant growth retardant is paclobutrazol. Its main absorption site is the xylem, and leaf spraying has poor effect. When applying, it should be determined according to the tree; a 5-year-old tree is generally applied with 7 to 30 grams (commercial amount, active ingredient 15%); robust trees with large canopies can be applied with 20 to 40 grams, and vice versa less. The dosage for forcing off-season flowering is larger, and for forcing normal-season flowering can be smaller. When applying, open a shallow trench of about 10cm under the canopy, apply evenly, cover with soil, and keep the soil moist within half a month. It takes effect only 2 months after application. But different varieties have different effects. For off-season cultivation it should be applied around March, and for normal-season flowering it can be applied in January. Applying paclobutrazol has the phenomenon of advancing flowering, so it is best to decide the application time according to the winter weather forecast. This chemical has a long residual effect period and must not be applied year after year, otherwise it will affect tree vigor growth, and weak trees are not suitable for it.

After flowering, the young fruits expand rapidly, and overly late inflorescences and empty flower branches should be cut off, so as to concentrate nutrients to supply the growth and development of the small fruits. After the second physiological fruit drop ends in late May, fruit thinning can be carried out. The purpose of fruit thinning is to retain fruit, because mango blooms heavily; if the weather is suitable during the flowering period, often a fruit panicle sets many small fruits. Although most small fruits naturally drop during physiological fruit drop, some fruit panicles still bear several small fruits, competing with each other for nutrients, dispersing nutrients, and affecting fruit development and commercial value. Generally, for high-yielding trees, leaving only one fruit per fruit panicle is enough; if the tree has a large canopy and a small fruit load, individual fruit panicles may retain two small fruits. The principle of fruit thinning is to keep the strong and remove the weak, keep the normal and remove the abnormal (those with pests, diseases and deformities). When thinning fruit, the removed small fruits should be cut off together with the fruit stalk.

6. Bagging to protect fruit

In early June, when the fruit grows to about the size of an egg, bagging should be carried out to protect the fruit. Bagging to protect fruit is one of the important links in mango health cultivation. It can prevent pest damage, reduce disease infection, lower mechanical damage, and improve fruit quality; at the same time it also reduces the number of sprayings and lowers pesticide residue contamination, etc.

The most economical bagging material is used newspaper. Used newspaper has relatively strong water and air permeability, will not stick to the fruit skin when wet, dries quickly, is not easy to mold, and is easy to obtain, low in cost and good in effect. One four-page used newspaper can be folded into 6 paper bags of the same size, and the bag seams are fastened with staples. The so-called “four-staple method” means one staple at the bottom, two staples on the sides, and after putting the fruit in, fold the corners of the bag opening and add one more staple to fix it.

Before bagging, a pesticide spray for disease prevention must be carried out. Trees sprayed with pesticide that day should be bagged completely that same day, to avoid re-infection by pathogens.

V. Management technical measures for mango after frost

For mango trees that have already suffered frost damage, remedial measures such as pruning can be used. Pruning is divided into two periods. The first period is 5 to 7 days after frost damage, first cutting off the already dried branches, to prevent the dried branches from drawing water and causing healthy branches to lose water; the second period is from late January to early February, pruning once more, cutting to the junction between the frost-damaged branches and the healthy branches. In addition, because frost damage is accompanied by gummosis, the gum should first be removed or the frost-cracked bark removed, then Bordeaux paste applied, prepared in the ratio 1:5:40 (copper sulfate: lime: water); where conditions allow irrigation, irrigate or sprinkle water appropriately. After the two prunings, appropriately supplement some fertilizer combining nitrogen, phosphorus and potassium as a foliar topdressing. For old trees, spray the parts not damaged by frost (that is, those still with green leaves) once with 0.3% to 0.5% potassium dihydrogen phosphate.

Remedial measures for seedlings are roughly similar to those for large trees, but attention must be paid to irrigation; where conditions allow, or where conditions can be created, irrigation must be carried out. If the dried part does not reach the graft union, then when pruning, leave as much of the scion part as possible, so that new shoots can grow again. Ungrafted seedling trees should be grafted again after they sprout anew.