Cultivation techniques

Temperature

General requirements for the annual average temperature of 16 ℃ -22 ℃, the absolute minimum temperature ≥ -7 ℃, the average temperature of January ≥ 4 ℃, ≥ 10 ℃ of the annual cumulative temperature of 5000 ℃ or more.

Soil

General requirements for the soil texture is good, loose and fertile, organic matter content is preferably more than 1.5%, the soil layer is deep, the thickness of the soil layer is preferably more than 60 centimeters, the water table is 1m or less, and pH 6-6.5 is appropriate.

Select time

The period of planting in the period after each new tip fills up to the next tip, the root system is easy to recover, the survival rate of seedlings is high, especially before the tip is the best. Generally in the spring and fall is appropriate, in September - l0 months after the autumn tip of the old mature or February - March before the spring tip sprouting planting. Frost damage in winter is preferred to plant in the spring, dry and hot valley areas should be planted in May - June before the rainy season, low heat valley areas with warm winters, under the condition of water, late October to early November planting survival rate is also high. Container seedlings or transplanting with soil is not limited by the season.

Density

The pomelo tree is a variety of citrus with a tall canopy.

Generally, the plant spacing of 5×6m is used, and 22-27 plants are planted per mu. However, in order to improve pre-production and economic benefits, the production of more than a reasonable plan of dense planting. Add a line in the center of the row spacing, so that the plant spacing is 5 × 3m, 44-54 plants per mu. If the canopy is more compact grapefruit (such as dwarf late grapefruit) according to the row spacing 3m, plant spacing 4m, 56 seedlings per mu. Planting should be noted that some varieties (such as Shatian pomelo) need to be configured pollinating varieties, the main species and pollinating varieties can be configured according to the ratio of 8-10:1.

Planting distance

In the establishment of the garden to determine the planting point, digging 1m × 1m × 1m planting holes, each hole with enough organic compost 50kg, phosphate fertilizer 3kg, plant straw or rice, wheat grass, etc., and soil mixed evenly filled into the hole, accounting for the depth of the hole 1/2-2/3, then backfilled with cooked soil, to avoid direct contact with fertilizer root root-burning, backfill should be higher than the ground 20-30 cm.

Pomelo tree planting should pay attention to shallow planting, can not be planted too deep, the seedling root system for trimming, cut the injured root system and too long roots, the root system evenly spread in all directions into the center of the planting pit, covered with fine soil, and then gently shaking the seedling up and down, so that the fine soil into the gap with the roots of the dense, and then fill in the soil step tightly, fill the root of the full irrigation water. The depth of planting must be so that the root neck is exposed to the ground, the grafting point must also be exposed to the ground after the soil sinks after the seedling is alive.

Management

Pomelo tree after planting, if the low temperature can be covered with straw insulation to prevent freezing. In case of drought can be cut 50% of the leaves to reduce water evaporation and improve the survival rate. Only irrigation before survival to keep wet, after the survival of 1-2 times a month after the application of clear fecal water, to promote the growth of new roots and sprouting and tresses, the rapid formation of productive canopy skeleton, to achieve three years to see the flowers, four years into production.

Improve the soil

1 ⒈ deep tilling hole expansion, improve the soil

Generally in the fruit harvest before and after the start, from the canopy periphery dripping line at the beginning of the canopy on both sides of the dug 50-60 cm deep, 50-60 cm wide ring-shaped hole expansion ditch, year by year, outward expansion of 40 cm -50 cm. In the expansion of the ditch backfill mixed with green manure, straw or rotted human and animal feces and urine, compost, stable manure, cake fertilizer, etc., topsoil on the bottom, the heart of the soil on the surface, and then the hole in the irrigation of water. 3-4 years to complete the expansion of the whole garden to change the soil work.

Peake additional organic fertilizer

Before and after the fruit harvest, combined with deep tilling and hole expansion, additional organic fertilizer (such as stable manure, compost, poultry manure, fish fertilizer, cake fertilizer, human urine, green manure, etc.). Expand the hole to change the soil in the crown on both sides of the tree dug 60-70 cm deep, 80-100 cm wide semicircular or rectangular deep ditch, in each hole about the application of stable fertilizer (or compost, green manure, etc.) 50 kg, cake fertilizer 1.5 kg, calcium magnesium phosphate fertilizer 2 kg, etc.. Buried in layers, a layer of soil layer of fertilizer to promote soil maturation, the purpose of soil improvement. Fertilizer in case of drought and no rain can be first irrigation after fertilization.

Intercropping

Pomelo in the first few years after planting, the canopy and root system is small, you can make full use of space, planting other crops. Reasonable planting can increase income, to achieve the "short to long", "garden to garden" purpose, but also can cover the orchard, reduce scouring, increase soil organic matter, improve soil fertility. Usually requires between sets of crops can effectively improve soil fertility, high yield, less fertilizer consumption, no and pomelo the same pests and diseases; plants are short, no climbing; shallow root system, do not compete with pomelo for water and fertilizer; have a high economic value.

Commonly used intercrops are soybeans, mung beans, peanuts, peas, camas and other leguminous crops; white chrysanthemum, licorice, ginseng, safflower, paeonia lactiflora, taiko ginseng and other medicinal plants; as well as potatoes, radish, ginger and other tubers, tuberous crops, and leafy vegetables, root vegetables and so on. Intercrop planting should generally be 50-80 centimeters away from the tree pan.

Sung mulching and soil cultivation

In the hot or dry season, it is recommended that the tree pan be covered with straw and other mulch at a thickness of 10cm-15cm, and the mulch should be kept at a distance of about 10cm from the root neck. Soil cultivation is carried out in winter after plowing and loosening the soil. 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.

Careful plowing

Can be carried out in summer, fall and after fruit picking, 3 times a year - 4 times, to keep the soil loose and weed-free. The depth of plowing is 8cm-15cm, deeper for sloping land, shallower for flat land. The rainy season should not be plowed.

Fertilization

When managing fertilization, the type of fertilizer is selected according to NY/T496-2002. Human and animal feces and urine, etc. need to be fermented at a high temperature of more than 50 degrees Celsius, with a fermentation period of more than 7d. Microbial fertilizer in the effective number of live bacteria must comply with the provisions of NY/T227.

1 ⒈, fertilization of young trees

1-3 years old pomelo tree fertilization should be applied diligently as the principle of thin fertilizer.

February-August, 1-2 times a month of clear manure. In the spring (February-March), summer (May-June), autumn (August) before the sprouting of tips, an additional application of fast-acting nitrogen fertilizer. In the year before production (the third year of autumn) to increase the application of phosphorus, potassium fertilizer, appropriate water control, to promote the differentiation of flower buds. Spray 0.2-0.3% potassium dihydrogen phosphate plus 0.3% urea on weak young trees, the effect is very good.

1-3 years old trees throughout the year the amount of fertilizer: urea 0.5-1kg per plant per year, or ammonia 1-2kg, calcium superphosphate 0.3-0.5kg, 10-20kg of organic compost, 80-100kg of clear dung water.

Peak, the adult fruiting tree fertilization

Adult pomelo tree production is high, the need for nutrients is especially high, we must fertilize in a timely manner to meet the needs of its normal growth and development. Its normal growth and development needs. Fertilization of adult trees, usually applied according to the following periods.

Spring (February-March) to apply a good spring flowering fertilizer. This time the fertilizer can promote the spring tips of the strong, for the flowering of the year to provide nutrients, but also for the next year to form a strong spring fruiting mother branch to lay the foundation, to overcome the size of the year, to achieve a good yield and stable production. Quick-acting nitrogen fertilizer (animal and human fertilizer, urea, carbon ammonia) is the main, accounting for 20% of the annual fertilizer. Generally 4-10 years old per plant urea 0.1-0.2kg or carbon ammonia 0.2-0.4kg, animal and human fertilizer 10-15kg, or compound fertilizer 0.2-0.3kg.

Summer (May-June) stabilization of fruit fertilizer pomelo tree is at the time of the summer end of the twig, and meet the young fruit growth period, the fertilizer should be carefully applied and to control the application of fast-acting nitrogen fertilizer in order to avoid the application of fertilizer caused by a large number of summer end of the twig, and cause a large number of young fruit. The first thing you need to do is to make sure that you have a lot of time and money to spend on your own. Can apply compound fertilizer 0.2-0.3kg/plant.

Autumn (August-September) fruit fertilizer when the fruit grows rapidly, the most nutrient needs. In order to meet the nutrient needs of the fruit growth and extraction, this fertilizer both to determine the current year's yield, but also affects the next year's yield, so this fertilization is very important, should be applied to the main phosphorus and potassium, supplemented by nitrogen fertilizer. The amount of fertilizer accounted for 45-50% of the year. Fertilizer can be used oil dry, marsh residue, compound fertilizer and so on.

Picking fruit before and after picking fruit fertilizer should be applied in a timely manner in winter to protect the leaf recovery fertilizer, supplementing the pomelo tree blossoming, fruit, twigging consumption of a large number of nutrients. This fertilizer should be applied early. Generally in late October to early November, when the pomelo tree buds began to differentiate, and is conducive to promote bud differentiation, to ensure that the next year's output. This time the fertilizer is also rotting organic compost-based, appropriate with the quick-acting nitrogen, phosphorus fertilizer, accounting for 25-30% of the annual fertilizer. 4-10 years old pomelo tree plants with 1-2kg of oil, phosphorus fertilizer 0.5-0.8kg, residual fertilizer 20-40kg rotting application, irrigation 20kg of human and animal fertilizer water.

3, fertilization methods

1) soil fertilization

Since the grapefruit absorbing roots are mainly distributed in the canopy drip line inside and outside the two sides of the soil layer, so the fertilizer must be applied in the canopy drip line under the absorbing root distribution of the densely populated parts. Usually near the drip line in the crown digging 50-60 cm deep groove or ring ditch, radial pit or ditch, will be rotted organic compost and soil mixed into the pit, and then apply manure to cover the soil to avoid volatilization of fertilizer, reduce the effectiveness of fertilizer. Fertilizer can be applied after irrigation in case of long drought without rain.

(2) outside the root fertilizer

Pomelo in addition to the root system can absorb nutrients, branches, leaves, fruits, etc. also have the ability to absorb nutrients. Artificial spray nutrient solution in the plant's crown, can meet the tree's demand for nutrients, known as extra-root fertilizer. Commonly used fertilizers for extra-root fertilizer are: urea, potassium dihydrogen phosphate, potassium sulfate, borax, magnesium sulfate and so on.

Pruning

⒈ young tree shaping

The grapefruit more natural round head shape. Stem height of 60 cm or so, choose to stay 4-5 main branches, each main branch to stay 3-4 secondary branches, no central leading stem, the formation of the lower large on the small, dense branch tips, the crown of a compact tree shape. When shaping, attention should be paid to the distribution of backbone branches in the crown evenly and reasonably. Juvenile shaping takes 3-4 years to complete, do not rush. Young trees with few branches and leaves, should promote the tip to expand the crown area is the main, can be cut or not cut the branches are not cut, affecting the canopy structure of the branches must be cut. Plastic surgery can take the method of pulling branches to utilize the branches.

Pearly fruit tree pruning

Pruning can be divided into winter pruning and summer pruning two periods.

Winter pruning is half a month after fruit picking and before spring buds sprout, usually in mid-late December to mid-January, reinvigorating the tree, and cultivating excellent fruiting mother branches.

Winter pruning should be handled separately according to different branch tips:

Sagging branches

Young trees can be appropriate to retain the sagging branches, so that it early fruit. But to adult trees, due to the pendulous branch growth potential is weak, poor results, can be bent in the pendulous part of the short cut, so that it grows upward.

Inner branch

The fruiting mother branch of pomelo is mainly spring, especially the leafless spring branch in the crown (because of few leaves, also known as light pole branch), is the main fruiting mother branch of pomelo. You can't just thin it out, only partially thin it out when it's too lush, to ensure that there are enough fruiting mother branches.

Cross-branching, overlapping branches

When there are cross-branching, overlapping branches, it is easy to cause the crown depression and poor branch growth, should be pruned. The principle of pruning is: leave empty to dense, leave strong to weak, and cut off the tips of branches growing inward.

Elongated branches

Elongated branches are easy to disturb the shape of the tree, and easy to disrupt the balance of the crown, should be cut in time. However, if it occurs in the canopy gap, can be considered to retain, and to appropriate short cut, promote the growth of branches, supplement the canopy gap.

For the crown of the dead branches, disease and insect branches are cut.

Summer pruning is generally carried out in late July to early August 15-20 days before the release of the fall, the purpose of which is to promote the pumping of robust fall, to restore the tree. The result of the grapefruit tree to stay in the spring, the most to stay in early August and then the autumn tips, the rest of the seasons out of all the tips of the branches to erase. In addition, the fallen flowers and fruit branches and leafless branches cut out, to achieve the strong flowers and fruit.

Fruit and flowers

⒈ flower promotion

Pomelo before entering the fruiting season, such as mismanagement is prone to the formation of exuberant long tree, young prosperous tree or adult bud differentiation of less pomelo trees to promote flowers. The specific measures are as follows:

(1) the exuberant long branches can be suppressed long, can be taken in late August to early September to support pulling branches, hanging branches.

(2) ring peeling or ring cutting time should be carried out in October after the autumn tips old. Ring cutting and ring peeling parts must be selected according to the different age of the tree. Beginning to enter the fruit of young trees selected in the main trunk and the main branches below the junction of the main trunk is relatively smooth and flat. Adult strong and prosperous grapefruit trees to choose in the main branch of the smooth and flat parts of the ring cutting is preferred.

①Ring peeling

With a knife in the cortex above and below the distance of 2-4mm in the middle of the ring cut two cuts, the two cuts in the middle of the cortex peeled off. Ring peeling to promote flowering should not be used full ring peeling, must leave a certain width of the range of non-ring peeling, according to the size of the trunk trunk circumference to increase or decrease the width of the non-ring peeling, generally leave 2-4 cm wide cortex non-ring peeling is appropriate, or leave 1-2 low small main branch non-ring peeling to feed the root system.

2 ring cut

Using an ordinary electric knife to ring cut the trunk 1 circle, to cut the bark cortex, do not hurt the xylem is appropriate.

3 ring stripping or ring cutting after the appearance of yellow leaves or leaf drop, it should be timely drenching or foliar spraying, and spraying the foliage with 100,000% of 2,4-D plus 0.3% of the urea solution.

(3) Application of plant growth regulators with 1000mg / L polystyrene or short-strengthin in the middle and late August onwards, every 20 days spraying, continuous spraying 2-3 times.

Peake strengthen pollination, improve yield

For varieties with poor self-pollination ability (such as Shatian pomelo), it is necessary to configure pollination varieties or artificial auxiliary pollination in order to obtain high yield. There are some unisexual fruiting ability of varieties (such as Koon Kee honey pomelo), can knot seedless fruit, but the fruiting rate is low, easy to crack the fruit, pollination of pollen to heterogeneous varieties of fruiting rate increased significantly, cracking the fruit to reduce, but the fruit seed more.

(1) pollination method

Select sour grapefruit as the best pollination varieties of trees. From the first flower, proceed from the growth of normal, robust pollination tree to collect just open or about to open the robust flowers, to be taken off with the flower stalk, the petals and stigma removed, the pollen directly to the stigma of the just open robust grapefruit flowers, generally 15-20 flowers per flower, pollination of each inflorescence pollination of 2-3 flowers.

Also available brush dipped in pollen point to the stigma of the newly opened pomelo flowers. If you use this method, you should first remove the pollinated anthers, so that the anthers cracked, pollen out, and then collected into a vial for use. In case of low temperature, the anthers can not be scattered pollen, the anthers can be placed under the lamp baking, so that the anthers cracked, scattered pollen, and then collected for use.

Pollen is best harvested with the grant, if the pollen is not used up, can be placed in dry conditions to save, but can not be sealed to keep the pollen has a high germination rate. Generally preserved at room temperature for 6 days, the pollen also maintains a 60% germination rate.

Also available pollen solution for pollination. The method is to use 0.5% of the pollen, borax 0.1%; urea 0.2%, honey 0.2%, 98% of water and other substances blended into pollen liquid, with a small sprayer sprayed on the stigma of grapefruit flowers. This method can improve the utilization rate of sour grapefruit flowers and increase the rate of fruit set.

Generally 300-600 flowers per tree pollination, divided into 3-4 times pollination can be. Pomelo flowers once pollinated stigma will be dark brown the next day, indicating that artificial pollination has been successful.

(2) pollination time

Sunny days in the morning at 8-11 am is the best time for pollination, followed by 4-7 pm. Artificial pollination must be carried out in batches, first open first, then open after the pollination.

3 thinning, fruit thinning, fruit setting

First buds (bud match head size and full bloom for flower thinning, 1 fruiting mother branch to stay 1-2 inflorescences, each inflorescence to stay 3-4 flowers, remove the head to stay in the middle of the normal flower.

Artificial fruit thinning is carried out twice. The first time in the first physiological fruit drop, only thinning small fruit, disease fruit, deformed fruit, dense weak fruit; the second in June after the second physiological fruit drop (in the young fruit thumb size and fist size), according to the leaf fruit ratio for fruit thinning, suitable leaf fruit ratio of 200-300: 1. Weak tree leaf fruit ratio moderately increased. Generally mastered in 10 years to generate annual tree strong tree fruit 80-100 for good, the tree excess fruit are thinned out. The number of small trees and weak trees set fruit discretionary reduction.

Sung bag

Sung bag can effectively reduce pesticide pollution, improve the appearance of quality, improve the quality of fruit, reduce production costs, is the production of pollution-free food is an important initiative. Pomelo fruit paper bags should be selected to resist wind and rain, good air permeability of citrus special paper bags, to a single layer of bags is appropriate. Shatin pomelo usually choose 25 cm × 40 cm; the bottom corners of the bag should have 1.5-2 cm leakage holes. Bag time to the second physiological fruit drop, young fruit diameter of 3-4 cm, about the beginning of June - the end of June is appropriate.

Bagging should be based on local pests and diseases occurring in the grapefruit garden comprehensive spraying 1 time, the use of pesticides in strict accordance with the GB4285 standards for the safe use of pesticides and GB/T8321 pesticide guidelines for the rational use of the requirements. Spraying liquid dry can start bagging.

Support the bag with fingers, loaded into the young fruit, the bag closed bundle in the fruiting branch or fruiting branch, do not set into the leaves, short-handled young fruit bag, can be appropriate pruning fruiting branch, along with the fruiting branch together with the method of the set. Paper bag with 26 # wire tie mouth, tight to not into the rain to the extent that the fruit picking 20-30 days before (about the middle of October) to remove the bag, in order to facilitate the coloring of pomelo fruit.

Harvesting

In order to ensure the quality of commercial fruit, the fruit should be used according to different purposes, to achieve the required maturity before harvesting. Different maturity of the fruit, its quality and storability are different. Harvested too early, the storage of the skin color pale, light flavor, acid, poor quality; too late harvesting although the storage of the initial quality is good, but because of its own resistance to disease and poor storage resistance, easy to lesions and rot in storage, the quality of the decline is also faster.

Usually harvested fresh fruits in the normal maturity of the fruit, showing the inherent quality characteristics of the variety (color, aroma, flavor and texture, etc.) when harvested. Fruit storage than fresh fruit should be harvested 7 days earlier - 10 days, processing fruit should be harvested 7 days later - 10 days.

Harvesting should pay attention to:

1, in case of rain, snow, fog, frosty weather, as well as water on the tree is not dry and windy, should not be harvested.

2, fruit picking personnel should first cut the nails flat, wear soft gloves, so as not to pick the fruit when the nails piercing the fruit.

3, the fruit branch away from the hand far, do not climb the branch pull fruit, so as not to pull loose fruit.

4, the strict implementation of double cut method. Generally a fruit of two cuts, the first cut from the fruits of 3-5mm cut, the second cut Qi fruits to cut the fruit stalk, make sure not to hurt the fruits of the fruits of the fruits of the fruits of the fruits of the fruits of the fruits of the fruits of the fruits of the fruits of the fruits of the fruits of the fruits, and to keep sepals intact.

5, the fruit into the fruit basket, or from the fruit basket into the fruit box (or fruit basket), must be gently held and put, not thrown and dumped. In order to avoid pressure injury to the fruit, picking fruit basket and picking fruit box to leave enough space, do not load too full, loaded to eight or nine percent full is appropriate.

Pest Control

The pests and diseases that harm the pomelo tree are more, common mites, mealybugs, leaf miner moths, anthracnose, etc., and the control should be based on the occurrence of various diseases, combined with spraying control.

(1) the end of February to early April before flowering, continuous spraying 2 times to control mites, while combining the prevention and control of other pests, the use of pesticides: insecticides + acaricides + fungicides.

(2) the young fruit after the flowers in mid-May to late June, continuous spraying 2 times, to prevent and control mealybugs, while combining the prevention and control of other pests, the use of pesticides: insecticides + fungicides.

(3) fall from mid-July to early September, 3-4 consecutive sprays, in order to prevent and control leaf miner moths as the main, combined with the prevention and control of phoenix butterfly, anthracnose, etc., the use of pesticides: insecticides + fungicides.

(4) mid-September to early October is the second peak of mite damage, should be sprayed 1-2 times to kill the mites, and at the same time concurrently treat other pests and diseases, the use of pesticides: insecticides + acaricides + fungicides.

(5) winter spraying a stone sulfur compound to clear the garden.

Insecticides can be used alternately, such as Lesben, trichlorfon, Methomyl, Daqongshen, etc. Fungicides can be selected carbendazim, tolbutane, zinc diclofenac, etc., acaricides can be selected from Kemet, mite, etc. Alternate spraying, spraying should be even and thoughtful.

Diseases

1 ⒈ foot rot

Also known as rotten root and stem scars. Harmful symptoms: mainly harmful to the trunk root neck, the affected plant trunk base bark rot, so that yellow leaves withered branches, tree weakness, yield decline, in severe cases, the whole plant withered. high incidence in July-August high-temperature rainy season.

Prevention methods:

(1) Scrape off the diseased part of the tissue part, and concentrate on burning. Apply fungicide and protective agent after scraping.

(2) commonly used drugs are: apply 20-40 ppm of 2.4-d followed by methyltropazine 100-200 times; Bordeaux liquid slurry, i.e., 1 kg of copper sulfate, 3 kg of quicklime, 15 kg of water mixture; the early stage of the disease or the onset of the disease or the absence of the onset of the disease with Yunsheng 900-1100 times the spray control.

Peak gum disease

Harmful symptoms: harm to the main trunk and main branches, affecting the tree, when serious, the spot extension "ring cut" trunk, resulting in plant branch death.

Prevention methods:

The first part of the disease of the rough skin scraped (now greenish-yellow appropriate), and then cut several longitudinal fissures, deep into the xylem, and then 80 times the polymyxin liquid or 50% Tolbutrazine or carbendazim 100-200 times the liquid treatment.

Pests

1 ⒈ red, yellow spider

Red spider is mainly harmful to the leaves, the affected leaves seriously lose their luster, grayish-white, causing defoliation, withered tips. Yellow spider damage makes the leaf blade deformed and twisted, causing leaf drop and withered tip. Harming period is generally from mid-April to early-mid June; September is the second harming peak.

Prevention methods:

(1) clear the garden in winter, spraying Pomerol 2-3 degrees of stone sulfur synthetics.

(2) Pharmaceuticals can be used flat mite 1500 times liquid in the spring and summer pumping the beginning of the period of spraying to protect the buds, or when there is an insect mouth occurs spraying control.

Peak blowing mealybugs, red wax mealybugs, vector-shaped mealybugs

Harmful symptoms: adults, larvae damage branches, leaves, fruits, and lead to the occurrence of sooty disease, the affected trees weak, withered branches, or in some cases, death.

Prevention methods:

The key to control mealybugs is in the larval stage, before the adults form wax shells, the end of March to the end of September is the peak of mealybugs, especially from the end of April to the middle of May is the key to control. It can be sprayed with 1000 times of liquid to prevent and control.

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