How to cultivate and manage grapefruit

First, planting: pomelo trees like warm, humid, need fertilizer and water, and require deep and fertile soil. Pomelo trees should pay special attention to planting in places where the soil is more fertile, where there is sufficient water or where the water source is good. 1. Planting time. It is generally suitable for the rainy season in spring and autumn, from the end of February to late April in spring, and from mid-September to mid-October in autumn. If possible, it can also be planted in other seasons, but it is not suitable to be planted under the conditions of bottom temperature in winter and summer drought in summer. 2. Planting density. Plant distance from 4x4 meters or 4x5 meters, generally about 40 mu, can also be dwarfed, densely planted, 50-60 plants per mu. 3. Planting method. (1) dig a 1-meter square pit before planting, apply a large amount of engine fertilizer and an appropriate amount of phosphate fertilizer as base fertilizer, and return to the soil 20-30 cm higher than the ground. (2) when planting, the seedlings are gently placed in the hole, planted in loose broken soil, the fine mud around the root mass is compacted by hand, and the graft joint is exposed to the ground. (3) after planting, the nest plate is 20 cm higher than the ground, and the fixed root water is sufficient.

Second, soil tillage: 1. Turn deeply and expand holes to ripen the soil. Deep ploughing and soil improvement and ripening soil must start from the establishment of the garden and expand year by year. Young trees can dig circular trenches on the periphery of planting and plough deeply year by year. The adult pomelo orchard can carry out a deep trench around the crown, with a depth of about 0.5-0.7 meters, and apply organic and inorganic fertilizers such as green manure in layers, and can also turn deeply every other year, every other row or every year. 2. Big green manure. Use the land to raise the land. Large kinds of green manure cover the ground, which can prevent erosion, reduce soil temperature, increase air humidity and restrain weeds, increase soil organic matter and improve soil fertility in summer. If we interplant legumes, vegetables, etc., it can also increase the early benefit, its stems, residual branches and leaves cover and turn into the soil, and increase the soil organic matter. 3. Cultivate the soil by ploughing. Intertillage combined with weeding, generally ploughing 3-4 times a year, that is, after fruit harvest in winter, in summer or autumn, combined with sowing and intercropping. The depth of planting and ploughing is 10-15 cm (combined with intercropping and sowing, properly deepened), the closer to the trunk, the shallower the tree trunk, so as to avoid the loss of big roots. Soil cultivation should be carried out before the dry season or after fruit harvest in winter. In the gentle slope zone, the soil is cultivated once every 3-4 years, and every other year in the places with large slope and serious erosion.

Third, fertilize. Young trees are small and their roots are young, so they should be applied frequently and thinly, 5-6 times a year, and the fruit trees should be fertilized 4 times, that is, Yang fertilizer, stable fruit fertilizer and strong fruit fertilizer. 1. Huanyang fertilizer (base fertilizer): the amount of fertilizer applied before and after fruit harvest accounts for half of the amount of fertilizer applied in the whole year, and a large amount of late-acting fertilizer such as green manure, compost, circle manure and cake fertilizer should be applied, combined with available nitrogen fertilizer and phosphate fertilizer. 2. Budding fertilizer (pre-anthesis fertilizer): generally carried out from February to March, this time the fertilizer should be based on available nitrogen fertilizer, mainly human and animal manure, and properly combined with urea. 3. Stable fruit fertilizer: apply quick-acting nitrogen fertilizer and phosphate fertilizer half a month before fruit drop in June, apply mature human and animal manure and spray 1% superphosphate leaching solution. 4. Strong fruit fertilizer: applied in the middle and late June, applying available nitrogen fertilizer and phosphorus and potassium fertilizer.

Fourth, irrigation and drainage. The pomelo tree is evergreen all the year round, the annual growth of branches is large, the fruit hanging period is long, the leaves are big and the fruit is big, and the requirement for water is high. The cultivation of pomelo must be irrigated to ensure its water requirements, irrigation should be based on the water needs of pomelo trees in the later stage and the drought at that time. Generally speaking, its annual growth and development process needs an appropriate amount of water, especially in spring bud germination and flowering, fruit growth is the most sensitive, there is spring drought, irrigation must be carried out. Pay attention to drainage in places with low terrain and high groundwater level or in the rainy season. Check the pomelo garden drainage system at any time before the rainy season or rainstorm season, repair and dredge it in time, so that the drainage is unimpeded.

Fifth, plastic surgery and pruning. The pomelo tree is strong and tall, under the condition of sufficient fertilizer and water, the top dominance is strong, the branches grow erect, it is easy to form an obvious tree shape of the trunk, and there are many new shoots. As a result, the rear branches droop because of heavy fruit, and the branches bend downward, resulting in the tree forming an umbrella shape. The light is not easy to penetrate into the inside of the crown and the declining fruit is small. Most of the fruiting mother branches of pomelo trees are inside the crown, which are biennial leafless branches (commonly known as claws). According to the growth and fruiting characteristics of pomelo, it is appropriate to choose "changing side trunk shape" and natural "happy shape" in production, the stem height should be 40-60 cm, the interval between main branches is 30-40 cm, and 5-6 main branches should be cultured. When pruning pomelo trees, we should make sure that the top is heavy, the square is light, the periphery is heavy, and the interior is light, that is, in the dense branches around the crown, the pruning is sparse, the top branches are heavy, and the inner branches are trimmed lightly, so that the internal light of the crown is good, the fruit is many and the quality is good. Generally, the slender leafless branches on the 3-4-year-old side branches of the crown are excellent fruiting mother branches, which must be preserved. For the side branches that are too long or disturb the tree shape and affect the balance of the tree potential, attention should be paid to thinning and cutting to achieve the purpose of ventilation.

Sixth, pest prevention and control. There are many diseases and insect pests harmful to pomelo, such as mites, scale, leaf miner, anthrax and so on. The main results are as follows: 1. From the end of February to the first ten days of April, two times of continuous spraying were used to control mites and other pests, and pesticides were used: pesticides + acaricides + fungicides. 2. From the middle of May to the end of June, the young fruit period after Xiehua was sprayed twice continuously, mainly to control scale and other pests, and pesticides: insecticides and fungicides were used. 3. From mid-July to early September in autumn, spraying continuously for 3-4 times, mainly to control leaf miner, but also to control Phoenix butterfly, anthracnose and so on, using pesticides: pesticides + fungicides. 4. The second peak of mite harm is from mid-September to early October. It should be sprayed 1-2 times to kill mites and treat other diseases and insect pests at the same time, using pesticides: insecticides + acaricides + fungicides. 5. Spray stone-sulfur mixture once in winter to clear the garden.

Insecticides can be used alternately, such as Lesbon, trichlorfon, trichlorfon, etc., fungicides can choose carbendazim, thiophanate, Dysen zinc, etc., acaricides can be sprayed alternately, and the spray should be uniform and thoughtful.

Cultivation and management techniques of high quality and high yield of pomelo

1. Strengthen the tip and promote it to turn green. When the spring shoot of the strong and prosperous tree is 4-7 cm, it is sprayed with 15% dint 600 times paclobutrazol to make the spring shoot short and strong, the inflorescence strong, and the crown of the tree crown sprayed with green Fenwei during the leaf development period of the spring shoot to promote the leaves to turn green. 2. covered with plastic film, moisturizing will keep warm. In summer and autumn, the temperature is high and the soil water evaporation is large, and the rows of orchards are covered with plastic film or interplanting low vegetables, peanuts and legumes. It is beneficial to the growth and development of pomelo trees, increase the yield of pomelo trees and increase the economic benefits of pomelo orchards. 3. Pollination at the right time to improve the fruit. (1) artificial pollination chooses sunny weather to pick back the blooming male flowers of pomelo trees, wrap the pollen in white paper, put it in a cloth bag and tie it around the human waist and wrap it around the body. After 24 hours, take out the pollen, add 0.1% borax and mix it with a brush or cotton swab on the grapefruit flower stigma. (2) after the insect pollination was mixed with 0.2% urea, 0.3% sugar, 1.2% bee sugar and 98% water, the pomelo style head was sprayed with a miniature sprayer at 8 am-10:00 pm on a sunny day and sprayed 2-3 times in a row to induce bees to pollinate and improve fruit setting. 4. Timely fruit thinning. When the young fruit grows to the size of the pea, the fruit thinning is carried out for the first time, mainly to remove small fruit, disease and insect fruit and deformed fruit. Generally, according to the tree potential bearing capacity of 1-1.5 times, when the fruit grows to the big finger mother, the second fruit thinning is carried out, at this time the fruit thinning requires that the fruit retained is of the same size and evenly distributed. 5. Young fruit transfer. When the grapefruit grows to the size of the egg, cut off the overdense young fruit or twin fruit and transfer it to the branch with less fruit, so that the nutrition supply is sufficient, the fruit is strengthened, and the yield is increased. 6. Protect flowers and fruits. Spray 0.1% Lufenwei foliar fertilizer plus 0.1% borax, add 0.2% ammonium molybdate, 0.2% potassium dihydrogen phosphate and 0.3% urea, then spray the crown twice (once every 7 days) at flower bud stage; spray the crown with 1 bag of anthocyanin and gibberellin 20x10-6 at 3/4, dissolve with alcohol and then spray the crown. During the physiological fruit drop period, the fruit pedicel was smeared once from mid-April to early May and once again from late May to mid-June after dissolving with 1 gram of cytokinin (ba) in alcohol to 200x10-6. 7. do a good job of disease prevention and control. (1) Control of flower bud maggots in the peak period of adult Eclosion, sprinkle on the ground with 0.8 kg of carbofuran granules and 25 kg of river sand per mu. Spray the canopy 1-2 times with 90% trichlorfon (or 80% dichlorvos emulsion) 600 times. Remove the damaged buds in time and bury them deeply after scalding them with boiling water. (2) to control the sagittal tip scale and blow cotton scale, spray and wash the firewood mixture 1-2 times in the first generation of young scale hatching period in the first and middle of May, and wash the firewood mixture (0.5 parts of washing powder + 1 part of diesel oil) to prepare 80-100 times liquid or 1500-2000 times liquid of 40% speed killing emulsion to use alternately. (3) Control of red and yellow spiders. Spray the canopy 1-2 times with 2000 times of Nisorang plus 80 times of isocarbophos or 2000 times of propargite with a small amount of diesel. (4) dry in winter. Use quicklime 6 kg, stone sulfur mixture 1 kg, salt 1 kg, omethoate 50 grams, water 15 kg pomelo tree trunk to prevent and control diseases and insect pests. 8. Strengthen the management of fertilizer and water. The tending period of young trees is mainly vegetative growth, and the crown of early fruiting and abundant trees is cultivated. Therefore, shoot promoting fertilizer and strong shoot fertilizer were applied once a year before and after spring, summer and autumn, and 5-8 kg of farm manure and 0.1-0.2 kg of urea were applied to plants. After entering the fruiting period, spring fertilizer was applied thinly in the first ten days of February, and 50 kg of farm fertilizer and 0.3-0.4 kg of urea were applied to plants. In the middle of May, the stable fruit fertilizer was skillfully applied, and the plant was applied 0.1% Lufenwei foliar fertilizer 1-2 times or 0.2% potassium dihydrogen phosphate and 0.3% urea mixed with external root topdressing. In the middle of July, the fertilizer of strengthening fruit and promoting shoot was applied again, and the plant was mixed with 60 kg of farm powder plus 1 kg of superphosphate and 2 kg of plant ash. In the middle and last ten days of September, deep application of fruit-picking and grafting fertilizer (also known as Fuzhuangfei), plant application of 60 kg of farm manure and 1 kg of oil cake to restore the tree potential. 9. Do a good job in plastic surgery and pruning. (1) pick the heart in time. When the growth length of the shoot in spring and summer is about 30 cm, pick the heart in time and remove the excess buds. (2) pruning and shaping. In autumn, measures such as bracing, pulling and hanging are taken to increase the opening angle, ease the growth potential and promote early fruiting. (3) ring cutting to promote flowers. In late September, the lateral branches were cut 3 times by staggering rings with a sharp knife to prevent the downward transport of nutrients produced by leaves, increase the accumulation of organic nutrients in leaves and effectively increase the amount of flowers in the following year. (4) controlling late autumn and winter shoots. The late autumn and winter shoots issued after the first ten days of November will consume a lot of nutrients, which is not conducive to the differentiation of flower buds in the next year. When the leaves of autumn shoots turn green and mature, spraying 300 times paclobutrazol inhibitor 1-2 times can effectively avoid winter shoots. (5) pruning and sparse proofreading. After fruit picking, 1 or 2 growing branches in the middle and upper part of the crown were removed to enhance the light transmission of the inner chamber. In pruning, it is necessary to grasp the principle of heavy on the top and light on the outside, heavy on the outside and light on the inside, more thinning and less pruning, cutting off overlapping branches, stranded branches, disease and insect branches, competitive branches, dry and withered branches and fruit handles, and three thinning and five remaining twigs for clustered branches, so that the shoot distribution is uniform, and the canopy side branches, short fruit branches, lower leafless branches and drooping branches are preserved as far as possible, so that the crown can be ventilated and transparent, so as to achieve high and stable yield in successive years. 10. Timely harvest. It is generally appropriate to harvest in late November, pick on a sunny day, and handle it gently during harvest, transportation and storage. When storing and keeping fresh, the fruit can be washed and sterilized with 2mam 4murd plus carbendazim solution, and then packed in a fresh-keeping bag.

Scientific fertilization of pomelo: fertilization of 1-and 1-3-year-old young trees. In order to strengthen the growth and high yield of young trees, multiple fertilizers should be applied according to the characteristics of multiple shoots of pomelo trees. Fertilization in front of shoots can promote hair shoots and make shoots grow healthily. Topdressing is mainly quick-acting fertilizer. The method of fertilization: apply frequently and less, and apply more spring shoot fertilizer. The fertilization time is February, May and July, respectively. If you expect to begin to bear fruit in the second year after planting, you should appropriately increase phosphorus and potassium fertilizer and reduce the amount of nitrogen fertilizer during the autumn shoot filling period. in order to promote flowers, strong trees can be sprayed with 0.3-0.6% potassium dihydrogen phosphate 2-3 times during flower bud differentiation (December). Weak trees spray 0.2% potassium dihydrogen phosphate plus 0.4-0.5% urea 3-4 times. A large amount of organic manure, green manure, phosphorus and potash fertilizer should also be added to lay the upper layer of the ground to promote the good development of horizontal roots and facilitate early fruit and high yield. Second, fertilization of fruiting trees. The fertilization of fruit trees is generally divided into four fertilizers, namely, returning sun fertilizer, promoting shoot fertilizer, stable fruit fertilizer and strong fruit fertilizer. 1. Huanyang fertilizer (base fertilizer). Fertilization time: before and after fruit harvest; the important role of fertilization: pomelo tree blossoms, resulting in the consumption of a lot of nutrients, in order to restore the tree potential, promote flower bud differentiation, enrich the fruiting mother branch, and ensure the nutrient needs of the next year, we must apply sufficient base fertilizer. The amount of fertilizer applied generally accounts for 50% of the amount of fertilizer applied in the whole year; the types of fertilizers used: late-acting fertilizers such as green manure, compost and cake fertilizer, and combined application of quick-acting fertilizer and phosphate fertilizer (calcium superphosphate is the best). Fertilization method: dig a ring ditch outside the crown, with phosphate fertilizer below and urea on top. 2. Accelerating budding fertilizer (flower bud fertilizer). Fertilization time: February to March; the important role of fertilization: it can promote spring shoot emergence, supply the need for flowering and fruiting, lay a good foundation for shoots in the current year and strong fruiting mother branches in the next year; can overcome annual fruit, and achieve high and stable yield. Therefore, fertilization is an important measure to increase production; the type of fertilization should be based on available nitrogen fertilizer, such as human feces and urine or urea, ammonium sulfate and so on. 3. Stable fruit and fertilizer. Fertilization time: half a month before the second physiological fruit drop (June); the important role of fertilization is to compensate for the nutrients consumed by flowering and young fruits, reduce fruit drop, increase fruit rate, and ensure high yield; fertilizer types: available nitrogen fertilizer and phosphate fertilizer, can also be applied into human feces and urine, spraying 1% calcium superphosphate leaching solution. 4. Strong fruit and fat. Fertilization time: before autumn shoots, from May to June; the important role of fertilization: from July to August, the fruit grows rapidly, and a large number of autumn shoots are pulled out at the same time, resulting in the contradiction of competing for nutrients and water; types of fertilization: in order to accelerate fruit growth and improve fruit quality, at the same time to promote the occurrence of autumn shoots, it is necessary to apply available nitrogen fertilizer and phosphorus and potassium fertilizer. Base fertilizer was generally applied to adult fruit trees, 150 kg of human and animal fertilizer was applied to each plant in February, 100 kg of human and animal fertilizer was applied to each plant in May, 150 kg of human and animal fertilizer was applied to each plant in July, and appropriate amount of calcium superphosphate was added.

Shaping and pruning of pomelo: through shaping and pruning, pomelo makes its crown shape plump, and achieves the goal of high yield and stable yield. First, make sure it is dry. The stem height should be 40-60 cm, and a total of 5-6 trunk should be cultivated. The biological characteristics of pomelo are different from those of other sweet oranges and red oranges. The trees are strong, tall and too large, and most or all of the fruiting mother branches are inside the crown. We must understand these characteristics in order to master the pruning technique. Second, the fruiting mother branch. The tip of the fruiting branch is called the fruiting mother branch. Results the mother branch can be divided into three types: 1. The small lateral branch on the large lateral branch, which grows weakly and can not protrude the vegetative branch of the crown. After it grows continuously for 2-3 years, it divides into leafless and fruiting mother branch, and shoots bear fruit. 2. Leafless branches, which bloom and sprout with insufficient nutritional conditions, generally do not blossom and bear fruit until three years. 3. Fallen flowers and fruit branches (commonly known as blind branches), they have no sprouting buds, they blossom and bear fruit the following year. Third, fruiting branches. It is formed by germination of a bud at the top of the fruiting mother branch or several buds near it. The fruiting branches include leaf fruiting branches, flowering and leafless fruiting branches and leafless fruiting branches. There are one to many flowers, and the fruiting branches of non-inflorescence and few-leaf inflorescences are the best. Fourth, the purpose and significance of pruning. The inside of the tree crown is well ventilated and transparent, the fruit-bearing mother branch in the inner hall is nutritious, the fruit is many and the quality is good. Fifth, pruning principle. Make sure that the outer space is not empty, the top is heavy, the four sides are light, the periphery is heavy, and the inside is not light. 6. Pruning methods. Pay attention to the preservation of the weaker leafless branches on the inner side branches of the crown, these are excellent fruiting mother branches; the branches with exuberant vegetative growth and leaves are too dense should be heavy-cut, and those with weak vegetative growth should be cut lightly. 7. Pruning time and branches to be cut off. After fruit picking, the upright and drooping branches in the crown should be cut off, and the dry and withered branches, disease and insect branches, shaded branches and heavy cross branches should be cut off. Summer shearing: in summer, wipe off some too dense, too prosperous new shoots, thinning too dense weak branches, short truncated long branches.

The flower and fruit of pomelo. First, promoting flowers. In order to make fruit trees blossom early, it is necessary to control the vegetative growth of tree potential, promote the growth center to reproductive growth, and promote flower bud differentiation in the year before fruit: 1. Control the vigorous growth of vertical roots, cultivate a large number of lateral roots and parallel roots, and promote flower bud differentiation. 2. Support, pull and drop the branches, increase the angle between branches and stems, weaken the vegetative growth and promote flower bud differentiation. 3. Young trees with prosperous growth will cut the lateral branches in 1-2 circles from September to October. 4. In autumn, pay attention to drainage, water control, and cut off part of the root system, resulting in plant physiological drought, in order to promote flower bud differentiation. Second, protect the fruit. 1. Increase tree nutrition, strengthen fertilizer and water management, retain leaves as much as possible, and prevent abnormal leaf fall. 2. Control the amount of flowers and get rid of those malformed flowers and overdense flowers. 3. Regulate spring shoots and erase summer shoots. Too many spring shoots and excessive consumption of nutrients will aggravate fruit drop, and spring shoots should be regulated after budding. Mainly wipe off the strong spring shoots (vegetative branches) in the upper part of the crown, more than 5 flower branches, and late spring shoots; when the summer shoots sprout, wipe off the young shoots many times until the fruit is fixed in the middle of July. 4. Prevent and control diseases and insect pests. Common diseases and insect pests are red and yellow spiders, leaf rollers, resin diseases and so on. 5. Spraying plant hormones. Such as cytokinin, phytoxin, Jin Yunda-120 and so on.

Pomelo pest control. First, foot rot (rotten scar). Harm symptoms: mainly harm the neck of the trunk root, the bark at the base of the main stem of the damaged plant decayed, so that the yellow leaves withered branches, the tree potential weakened, the yield decreased, and when serious, the whole plant withered. The incidence is high in the high temperature and rainy season from July to August. Prevention and treatment methods: 1. Scrape off the tissue of the disease department and burn it centrally. Apply fungicide and protective agent after shaving. 2. The commonly used drugs are: apply 20-40ppm 2.4 times followed by methyl topiramate 100200 times, Bordeaux liquid, that is, the mixture of copper sulfate 1 jin, quicklime 3 jin, water 15 jin; spray prevention and treatment with Yunsheng liquid at the initial stage or before the disease. Second-rate glue disease. Harm symptoms: harm the trunk and main branches, affect the tree potential, when serious, the disease spot expand "ring cut" the trunk, resulting in plant branches withered. Prevention and treatment: first scrape off the rough skin of the disease (now bluish yellow is appropriate), and then longitudinally cut several cracks, deep to the xylem, and then with 80 times the multi-effect mold solution or 50% thiophanate or carbendazim 100-200 times solution. Third, red and yellow spiders. The red spider mainly harms the leaves. When the damaged leaves are serious, they lose their luster and show grayish white, causing fallen leaves and withered shoots. Yellow spiders cause leaves to deform and twist, resulting in fallen leaves and withered shoots. The peak period of damage is from the middle of April to the first and middle of June, and September is the second peak. Prevention and control methods: 1, clear the garden in winter, spray Baume 2-3 degrees stone sulfur mixture. 2. 1500 times liquid of flat mite can be used to protect buds at the beginning of emergence in spring and summer, or to control when insect population occurs. Fourth, blow cotton scale, red wax scale, sagittal scale. Harmful symptoms: adults and larvae harm branches, leaves, fruits, and lead to the occurrence of soot disease, injured trees grow weak, branches withered, heavy people die. Control methods: the key to the control of scale insects lies in the larval stage, concentrated spraying before the adult forms wax shell, and the peak period of scale insect damage is from the end of March to late September, especially from late April to mid-May. 1000 times of the solution can be used for spray control. Fifth, the leaf roll moth. Harmful symptoms: the larvae endanger the young leaves, young fruits and flower buds. The larvae often spin silk to fix the young fruits and young leaves together and drill into the fruit to feed, so that the young fruit turns yellow and falls off. Control methods: 1. Clear the garden in winter and remove the overwintering larvae. 2. Insecticide control should focus on 1-2 times when the insect population density is high after anthesis and larval stage. 3. Choose pesticides: 5000 times of enemy killing EC, 1000 times of dichlorvos, 8 times of 1000 times of enemy kill, and 1500 times of victory.

Preparation and use of stone-sulfur mixture: the objects of stone-sulfur mixture are powdery mildew, rust, rot, brown spot, red spider, shell insect, etc., and its raw material ratio is quicklime: sulfur: water = 1:2:10 (weight ratio). The method of boiling is to take 1 part of quicklime and pour it into boiled water to boil and remove the lime residue. Then slowly pour 2 portions of sulfur powder into a paste with a small amount of water, pour and stir, and continue to boil for another 45 minutes to an hour. When the solution turns reddish brown and the residue is yellowish green, it can cease fire, and after the residue is filtered out, it will be the original solution of stone-sulfur mixture. The method of use is that Baume 4-5 degree diluent can be sprayed in winter, 0.2-0.3 degree Baume diluent is used in the growing season, and 0.3-0.5% washing powder is added when it is used, the prevention and control effect is better. Dilution ratio of adding water = (concentration of raw solution minus use concentration) divided by use concentration = number of kilograms of water needed to be added.