temperature

Generally, annual average temperature 16℃-22℃, absolute minimum temperature ≥-7℃, monthly average temperature 1≥4℃, and annual accumulated temperature ≥ 10℃ above 5000℃.

land

Generally speaking, the soil is required to be good in texture, loose and fertile, with organic matter content above 1.5%, deep soil layer, soil layer thickness above 60 cm, groundwater level below 1m and pH value below 6-6.5.

opportunity

When planted from each new shoot to the next, the root system is easy to recover and the seedling survival rate is high, especially before the new shoot. Generally, it is suitable in spring and autumn, and should be planted after the autumn shoots mature in September 9- 10/October or before the spring shoots sprout in February-March. Where there is frost damage in winter, it should be planted in spring, in dry-hot valley area before the rainy season comes from May to June, and in low-heat valley area, it is warm in winter. Under the condition of water supply, the survival rate of 65438 ~/kloc-0 in late June 165438 in early October is also high. Container seedlings or transplanting with soil are not limited by season. ?

density

Pomelo is a citrus tree with a high crown.

Generally, the plant spacing is 5×6m, and 22-27 plants are planted per mu. However, in order to improve the early yield and economic benefits, reasonable planning and close planting are often used in production. Add a row in the middle of the row spacing to make the row spacing 5×3m, and plant 44-54 plants per mu. For example, grapefruit with compact crown (such as short late pomelo) has a row spacing of 3m and a plant spacing of 4m, with 56 plants per mu. It should be noted that some varieties (such as Shatian pomelo) need to be pollinated, and the ratio of main cultivated varieties to pollinated varieties can be 8- 10: 1. ?

Planting distance

After determining the planting site, dig1m×1m planting holes, apply 50kg organic compost and 3kg phosphate fertilizer to each hole, mix them evenly with soil, fill them into the holes, occupying the hole depth of 1/2-2/3, and then backfill the mature soil to avoid them.

When planting pomelo trees, we should pay attention to shallow planting, not too deep planting. The root system of seedlings should be trimmed, the injured root system and the excessively long root system should be cut flat, the root system should be spread evenly around and placed in the center of the planting pit, covered with fine soil, then the seedlings should be gently shaken up and down to make the fine soil enter the gap and closely connect with the root system, and then the soil should be filled and the root water should be filled. The planting depth must be such that the root neck is exposed to the ground, and the grafting point should also be exposed to the ground after the soil sinks after the seedlings survive.

operate

After planting pomelo trees, straw can be covered to keep warm to prevent freezing at low temperature. In case of drought, 50% of leaves can be cut off to reduce water evaporation and improve the survival rate. Just keep wet with water before you survive. After survival, manure cleaning water should be applied 1-2 times a month to promote the growth of new roots, buds and shoots, and quickly form a high-yield crown skeleton, so that flowers can be seen in three years and put into production in four years.

improve soil

1.

Generally, it is carried out before and after fruit harvesting. Starting from drip line, the periphery of the crown, an annular pit-expanding ditch with a depth of 50-60 cm and a width of 50-60 cm is dug on both sides of the crown, and the pit is expanded outward by 40 -50 cm every year. When backfilling the reaming ditch, green manure, straw or decomposed human and animal manure, compost, manure, cake fertilizer, etc. are added. Put the topsoil on the bottom layer and the core soil on the top layer, and then fill the hole with enough water. In 3-4 years, the hole enlargement and soil improvement of the whole park should be completed.

4. Increase the application amount of organic fertilizer.

Before and after fruit harvesting, combined with deep digging and hole enlargement, apply organic fertilizer (such as manure, compost, poultry manure, fish manure, cake manure, human manure, green manure, etc.). ) is added. When expanding holes to improve soil, semi-circular or rectangular deep ditches with a depth of 60-70 cm and a width of 80- 100 cm are dug on both sides of the crown, and about 50kg of manure (or compost, green manure, etc.) is used. ), 65438+ cake fertilizer 0.5kg, calcium magnesium phosphate fertilizer 2kg, etc. Apply to each hole. Layered burial, one layer of soil and one layer of fertilizer, promotes soil maturation and improves soil. In case of long drought and no rain during fertilization, water can be poured before fertilization.

3. Intercropping.

In the first few years after planting, the crown and root system of grapefruit are small, so it can make full use of space and interplant other crops. Reasonable interplanting can not only increase income and achieve the purpose of "growing with short crops" and "cultivating gardens with gardens", but also cover orchards, reduce erosion, increase soil organic matter and improve soil fertility. Intercropping crops usually requires effective improvement of soil fertility, high yield, low amount of chemical fertilizer, and no pests and diseases like pomelo trees; Plants are short and have no climbing; The root system is shallow and does not compete with pomelo for water and fertilizer; Has high economic value.

Common intercropping crops has leguminous crops such as soybeans, mung beans, peanuts, peas and wild peas; Medicinal plants, such as chrysanthemum, licorice, codonopsis pilosula, safflower, peony and pseudostellaria heterophylla; As well as root tuber, tuber crops, leafy vegetables and root tuber vegetables, such as potatoes, radishes and ginger. Intercropping crops should generally be 50-80 cm away from the tree tray.

4. Cover the soil and raise the soil.

In high temperature or dry season, it is suggested to cover the tree tray with straw with the thickness of 10 cm-15 cm, and keep the distance between the cover and the root neck about 10 cm. Soil cultivation is carried out after intertillage and loosening in winter. It can be cultivated into pond mud, river mud, sandy soil or fertile soil near citrus orchards with a thickness of 8 cm-10 cm.

Step 5 cultivate

It can be carried out in summer and autumn and after fruit picking, and intertillage 3 -4 times a year to keep the soil loose and free from weeds. The depth of intertillage is 8 cm-15 cm, the sloping land should be deep and the flat land should be shallow. Not suitable for intertillage in rainy season.

Fertilize soil or land

In fertilization management, fertilizer types are selected according to NY/T496-2002. Human and animal feces and urine need to be fermented at a high temperature above 50℃ for more than 7 days. The number of effective viable bacteria in microbial fertilizer must meet the requirements of NY/T227.

1. Fertilize young trees

Fertilization of 1-3-year-old pomelo trees should be based on the principle of applying thin fertilizer frequently.

Fecal cleaning water 1-2 times a month from February to August. Before spring shoots (February-March), summer shoots (May-June) and autumn shoots (August) germinate and sprout, apply quick-acting nitrogen fertilizer again. One year before production (autumn of the third year), apply more phosphorus and potassium fertilizer, properly control water and promote flower bud differentiation. Spraying 0.2-0.3% potassium dihydrogen phosphate and 0.3% urea on weak young trees is effective.

Annual fertilizer application for 1-3-year-old trees: 0.5- 1 kg urea per plant, or 1-2 kg urea, 0.3-0.5 kg calcium superphosphate, 10-20 kg organic compost, and 80- 100 kg clean.

4. Fertilization of adult fruit trees

Adult pomelo trees have high yield and need a lot of nutrition, so they should be fertilized in time to meet the needs of their normal growth and development. Fertilization of adult trees is usually carried out in the following periods.

Spring (February-March) should be well applied with spring flowering fertilizer. At this time, fertilization can promote the robustness of spring shoots, provide nutrients for flowering and fruiting in the same year, and lay the foundation for forming robust spring shoots and fruiting mother branches in the next year, thus overcoming the big and small years and realizing high and stable yield. Available nitrogen fertilizer (human and animal fertilizer, urea, ammonium bicarbonate) is the main fertilizer, accounting for 20% of the annual fertilization. Generally, 0.10.2kg urea, 0.2-0.4kg urea,10-15kg human and animal manure or 0.2-0.3kg compound fertilizer are applied to each 4- 10 annual plant.

In summer (May-June), pomelo trees are in the period of sprouting and tillering in summer, and meet the growth period of young fruits. This fertilization should be careful, control the available nitrogen fertilizer, and avoid a large number of young fruits falling after fertilization. 0.2-0.3 kg/plant of compound fertilizer can be applied.

In autumn (August-September), fruits grow rapidly and need nutrition most. In order to meet the needs of fruit growth and topping, this fertilizer not only determines the yield of the current year, but also affects the yield of the next year. Therefore, this fertilization is very important, mainly applying phosphorus and potassium, supplemented by nitrogen. Fertilization accounts for 45-50% of the whole year. The fertilizer can be drying oil, biogas residue and compound fertilizer.

Before and after fruit picking, winter leaf-preserving and rejuvenation fertilizer should be applied in time to supplement the large amount of nutrients consumed by pomelo trees during flowering, fruiting and bamboo shoots. Fertilization should be done early at this time. Generally, it is applied when the flower buds of pomelo trees begin to differentiate from late June 65438+ 10 to early October165438+10, which is beneficial to promote flower bud differentiation and ensure the next annual output. This fertilization is mainly based on decomposed organic compost, properly combined with available nitrogen and phosphorus fertilizers, accounting for 25-30% of the annual fertilization. 4- 10 year old pomelo trees were applied with oil cake 1-2 kg, phosphate fertilizer 0.5-0.8 kg, residual fertilizer 20-40 kg after decomposition, and human and animal manure 20 kg.

3. Fertilization method

(1) Soil fertilization

Because the absorption roots of grapefruit are mainly distributed in the soil layers on the inner and outer sides under the drip line, it is necessary to fertilize the parts where the absorption roots are densely distributed under the drip line. Usually, ditches or annular ditches, radial pits or ditches with a depth of 50-60 cm are dug near the drip irrigation line of the crown, and the decomposed organic compost is mixed with soil and applied in into the pit, and then manure is applied and covered with soil, so as to avoid fertilizer volatilization and reduce fertilizer efficiency. In case of long drought and no rain during fertilization, water can be poured before fertilization.

(2) Topdressing outside the roots

Besides roots, the branches, leaves and fruits of grapefruit also have the ability to absorb nutrients. Artificial spraying of nutrient solution on the crown of plants can meet the nutritional needs of trees, which is called topdressing outside the roots. Commonly used fertilizers for topdressing outside roots are: urea, potassium dihydrogen phosphate, potassium sulfate, borax, magnesium sulfate and so on.

decrease

1. Young tree shaping

Grapefruit mostly adopts natural round head shape. The height of the stem is about 60 cm, 4-5 main branches are selected, and 3-4 auxiliary branches are reserved for each main branch. There is no central main stem, forming a tree with big bottom and small top, dense branches and dense crown. Attention should be paid to the uniform and reasonable distribution of main branches in the crown during plastic surgery. Young plastic surgery takes 3-4 years to complete, so don't rush for success. Young branches and leaves are few, so the crown area should be expanded mainly by promoting branches. Don't cut any branches that can or can't be cut, but the branches that affect the crown structure must be cut. Branches can be used to pull branches during plastic surgery.

2. Pruning of fruit trees.

Pruning is divided into two periods: winter pruning and summer pruning.

Pruning in winter is carried out half a month from fruit picking to spring bud germination, generally from the middle and late June of 65438+February to the middle of June of 65438+1October, so as to rejuvenate the trees and cultivate excellent fruiting mother branches.

Winter pruning should be handled according to different branches:

Pendulous branch

Young trees can keep drooping branches properly to make them bear fruit early. However, for adult trees, because the drooping branches are weak and the effect is not good, they can be cut short at the bent and drooping parts to make them grow upwards.

Intracavity branch

The fruiting branches of grapefruit are mainly spring shoots, especially leafless spring shoots (also called bare branches because of few leaves) in the crown, which are the main fruiting branches of grapefruit. You can't delete it casually, only partially delete it when it is too dark, to ensure that there are enough fruit branches.

Overlapping branch

When crossing branches and overlapping branches appear, it is easy to cause canopy depression and poor growth of new shoots, which should be pruned. The principle of pruning is: leave white space to remove density, leave strong to remove weakness, and cut the branches that grow inward.

Tender strip

Long branches are easy to disrupt the tree shape and destroy the balance of the crown, so they should be cut off in time. However, if it occurs in the gap of the crown, it can be considered to keep it and prune it properly to promote the growth of branches and supplement the gap of the crown.

Dead branches, pests and diseases on the crown should be cut off.

Summer pruning is usually carried out from late July to early August, 20 days before 15- autumn shoots are released, in order to promote autumn shoots to be strong and restore tree vigor. As a result, the pomelo trees kept the spring shoots, most of which were the autumn shoots in early August, and all the branches in other seasons were erased. In addition, the fallen flowers and fruit branches and leafless branches are cut off to achieve strong flowers and fruit protection. ?

Guo Hua

1. Promote flowers.

Before grapefruit enters the full fruit period, if it is not well managed, it is easy to form a prosperous tree. Promote the flowering of young flourishing trees or adult pomelo trees with less flower bud differentiation. Specific measures are as follows:

(1) can inhibit the growth of flourishing branches, and can be hung from late August to early September.

⑵ girdling or girdling time should be 10 month after autumn shoots mature. The girdling and girdling parts must be selected according to different tree ages. The young trees that began to bear fruit were selected on the relatively smooth trunk below the intersection of the trunk and the main branch. It is best for adult Wang Zhuang pomelo trees to choose the part with smooth and flat main branches for cutting.

① girdling

Cut two knives in the middle of the cortex at a distance of 2-4mm and peel off the cortex between the two knives. Full girdling is not suitable for flower promotion, and a certain width must be left without girdling. The width of girdling can be increased or decreased according to the circumference of trunk. Generally, it is advisable to leave 2-4 cm wide cortex without girdling, or 65,438+0-2 low branches without girdling to support the root system.

② Circumferential cutting

Cut the trunk of the tree 1 time with an ordinary electrician's knife, so as to cut only the bark layer of the tree without hurting the xylem.

(3) If yellow leaves or fallen leaves appear after girdling or girdling, water should be sprayed or sprayed on the leaves in time, and 0.3% urea solution should be added to the leaves to110002,4-d.

⑶ Plant growth regulator 1000mg/L paclobutrazol or chlormequat chloride should be sprayed once every 20 days, and sprayed continuously for 2-3 times from the middle and late August.

4. Strengthen pollination and increase yield.

For varieties with poor self-pollination ability (such as Shatian pomelo), pollinated varieties or artificial pollination are needed to obtain high yield. For some varieties with strong parthenocarpy (such as Guanxi honey pomelo), seedless fruit can be produced, but the fruit setting rate is low and it is easy to crack. The pollination fruit setting rate of different varieties was significantly improved, and the fruit cracking was reduced, but the fruit seeds were more.

(1) pollination method

It is best to choose sour pomelo as pollination variety tree. From the beginning of flowering, we began to collect healthy flowers that have just opened or are about to open from pollinated trees with normal growth and vigorous tree growth. Take it off with the flower stalk, remove the petals and stigma, and directly pollinate the stigma of the healthy pomelo flower that has just opened. Generally, 15-20 flowers can be given to each flower, and 2-3 flowers can be pollinated to each inflorescence during pollination.

You can also dip the pollen into the stigma of the newly opened grapefruit flower with a brush. If this method is adopted, the pollinated anthers should be removed first, so that the anthers will split and the pollen will be scattered, and then collected and put into small bottles for later use. At low temperature, when the pollen can't be released from the anther, the anther can be baked under electric light to crack and release the pollen, and then collected and utilized.

Pollen is best harvested and sown. If the pollen can't be used up for a while, it can be stored under dry conditions, but it can't be sealed to keep the pollen germination rate high. Usually, after 6 days storage at room temperature, pollen still has 60% germination rate.

Pollen liquid can also be used for pollination. The method is to use 0.5% pollen and 0. 1% borax; 0.2% urea, 0.2% honey and 98% clear water are mixed to form pollen liquid, which is sprayed on the stigma of pomelo flower with a small sprayer. This method can improve the utilization rate and fruit setting rate of sour pomelo flowers.

Generally, each tree pollinates 300-600 flowers, which can be pollinated 3-4 times. Once the grapefruit flower is pollinated, the stigma will be dark brown the next day, indicating that artificial pollination has been successful.

⑵ Pollination time

The best pollination time is 8- 1 1 in sunny morning, followed by 4-7 pm. Artificial pollination must be carried out in batches, first open and then give, then open and then give.

[13] Sparse flowers and set fruits.

At the initial bud stage (the size of the matchhead becomes smaller at the bud and flowering stage, 1 fruiting mother branch leaves 1-2 inflorescences, each inflorescence leaves 3-4 flowers, and the middle normal flowers are left after the head and tail are removed.

Manual fruit thinning is carried out twice. After the first physiological fruit drop, only small fruit, diseased fruit, deformed fruit and dense weak fruit are sparse; The second time, after the second physiological fruit drop in June (when the young fruit has a big thumb and a big fist), the fruit should be thinned according to the leaf-fruit ratio, and the suitable leaf-fruit ratio is 200-300: 1. The proportion of weak leaves in fruits increased moderately. Generally speaking, it is better to set 80-100 strong trees in a year of10, and the redundant fruits on the trees should be thinned out. The number of fixed fruits of young trees and weak trees decreased.

4. Bagging.

Bagging can effectively reduce pesticide pollution, improve appearance quality, improve fruit quality and reduce production cost, which is an important measure to produce pollution-free food. The grapefruit paper bag should be a special paper bag for citrus with good weather resistance and good air permeability, and a single-layer bag is suitable. Shatian pomelo is generally 25 cm× 40 cm; There should be 1.5-2 cm water leakage holes at the two corners of the bottom of the bag. Bagging time should be from the first ten days of June to the end of June after the second physiological fruit drop, when the transverse diameter of young fruit is 3-4 cm.

Before bagging, spray 1 times on pomelo orchards according to the occurrence of local pests and diseases, and use pesticides in strict accordance with GB4285 Standard for Safe Use of Pesticides and GB/T832 1 Guidelines for Rational Use of Pesticides. After the spraying liquid is dried, it can be bagged.

Open the bag mouth with your fingers, put the young fruit in, tie the bag mouth to the fruiting branch or the fruiting mother branch, and don't put it in the leaves. When bagging young fruits with short stalks, the fruiting mother branches can be appropriately pruned and put together with the fruiting mother branches. The paper bag should be tied tightly with 26# iron wire, and the tightness should not get wet, and the bag should be picked 20-30 days before fruit picking (about 65438+1mid-October) to facilitate the coloring of pomelo fruit.

choose

In order to ensure the quality of commercial fruits, fruits should be harvested after reaching the specified maturity according to different uses. The quality and storability of fruits with different maturity are different. Premature harvest, light skin color, weak flavor and poor quality. Although the quality is good at the initial stage of storage, the disease resistance and storability of causality itself are poor, and it is easy to get sick and rot during storage, and the quality declines rapidly.

Usually, fresh fruit is harvested when the fruit matures normally and shows the inherent quality characteristics of the variety (color, aroma, taste, taste, etc.). ). Stored fruits should be harvested 7 days-10 days earlier than fresh fruits, and processed fruits should be harvested 7 days-10 days later.

Attention should be paid to when harvesting:

1. If it's raining, snowing, foggy, frosty, the water on the tree is wet, and the wind is strong, don't pick the fruit.

2. People who pick fruits should first cut their nails flat and put on soft gloves to avoid being stabbed by nails when picking fruits.

3. When the fruit branch is far away from the hand, don't climb the branch to pull the fruit, so as not to loosen the fruit pedicle.

4, strictly implement the double shear method. Generally, a fruit is cut twice, the first time is 3-5mm away from the fruit stalk, and the second time is to cut off the fruit stalk without damaging the fruit stalk and keeping the sepals intact.

5, fruit into the fruit basket, or from the fruit basket into the fruit box (or fruit basket), must be handled with care, not littering and dumping. In order to avoid crushing the fruit, the fruit picking baskets and boxes should have enough space, not too full, and should be filled to 80% to 90%.

Extended data pest control

There are many pests and diseases that harm pomelo trees, such as mites, scale insects, liriomyza sativae, anthracnose and so on. Control should be based on the occurrence characteristics of various diseases, combined with spray control.

(1) Before flowering, spraying pesticides twice continuously, mainly to control mites, and combining with other pests, using pesticides: insecticide+acaricide+bactericide.

⑵ During the young fruit period from mid-May to late June after flowering, spraying chemicals twice continuously, mainly to control scale insects, and combining with other pests, using pesticides: insecticide+bactericide.

(3) Spraying continuously for 3-4 times from mid-July to early September in autumn, mainly to control leaf miner, butterfly and anthracnose, using pesticide: insecticide+bactericide.

(4) 10 is the second peak of mite damage from mid-September to early June, so 1-2 times should be sprayed to treat other pests and diseases while killing mites. The pesticides used are insecticide+acaricide+bactericide.

5] Spray a mixture of lime and sulfur to clean the garden in winter.

Insecticides can be used interchangeably, such as chlorpyrifos, trichlorfon and mirex. The bactericide can be selected from any one of carbendazim, thiophanate and zineb. And acaricide can be sprayed alternately, evenly and thoughtfully.

disease

root rot

Also known as rotten scar. Harmful symptoms: It mainly harms the root and neck of the trunk, and the bark at the base of the trunk of the affected plant decays, resulting in yellow leaves and dead branches, weak tree potential and decreased yield. In severe cases, the whole plant will die. The incidence rate is high in high temperature and rainy season from July to August.

Prevention and control methods:

(1) Scrape off the tissue of the affected part and burn it centrally. Apply bactericide and protective agent after scraping.

⑵ The commonly used drugs are: 20-40ppm of 2.4-d followed by 100-200 times of thiophanate-methyl; Bordeaux pulp, that is, the mixed solution of copper sulfate 1 kg, quicklime 3 kg and water 15 kg; At the initial stage of the disease or at the time of no disease, Yun Sheng 900- 1 100 times liquid spray was used for prevention and treatment.

6. gummosis

Harmful symptoms: it harms the trunk and main branches and affects the tree potential. In severe cases, the diseased spots will enlarge the trunk and cause the branches of plants to die.

Prevention and control methods:

Scrape off the rough skin of the affected area (now it is appropriate to use bluish yellow), then cut several cracks longitudinally to reach the xylem, and then treat it with 80 times of multi-effect mildew solution or 50% thiophanate or carbendazim 100-200 times of solution.

insect pest

1. Red and yellow spiders

Red spider mainly harms leaves. When the leaves are seriously damaged, they lose their luster and are grayish white, resulting in defoliation and leaf tip withering. The damage of the yellow spider makes the leaves deformed and twisted, resulting in deciduous leaves and dead tips. The peak period of harm is generally from mid-April to mid-June; September is the second peak of harm.

Prevention and control methods:

(1) Clear the garden in winter, and spray Bomei 2-3 degree lime-sulfur mixture.

⑵ This medicine can be sprayed with acaroid mite 1500 times solution in spring and summer to protect buds or control insect population.

4. Blow scale, red scale and arrow scale.

Harmful symptoms: adults and larvae harm branches, leaves and fruits, leading to the occurrence of soot disease, the damaged trees grow weak, branches wither, and severe cases die.

Prevention and control methods:

The key to control scale insects lies in the larval stage. Spraying chemicals before adults form wax shells is the peak of scale damage from the end of March to the end of September, especially from the end of April to the middle of May. Spray control can be carried out with 1000 times solution.

References:

Grapefruit-Baidu Encyclopedia