A Detailed Guide to Cultivation Methods for Promoting Flowering and Fruiting in Pomelo Trees

Promoting flowering

If you want the fruit tree to bloom early, you must control the vegetative growth of the tree's vigor in the year before fruiting, prompting its growth center to shift toward reproductive growth, thereby promoting flower bud differentiation, so as to achieve the goal of early flowering in the fruit tree:

1. Control the vigorous growth of the tree's vertical roots and cultivate more lateral roots and parallel roots; the massive growth of lateral roots and parallel roots will promote flower bud differentiation;

2. Use methods such as propping, pulling and weighting down on the branches to increase the angle between branches and trunk, thereby weakening vegetative growth and promoting flower bud differentiation;

3. For vigorously growing young trees, perform 1-2 rings of girdling on the lateral branches in September-October;

4. In autumn, pay attention to drainage and water control, and cut off part of the root system to create a physiological drought condition in the plant, thereby promoting flower bud differentiation.

Fruit retention

1. After flowering, increase the tree's nutrition, strengthen fertilizer and water management, retain leaves as much as possible, and prevent abnormal leaf drop;

2. Pay attention to controlling the amount of flowers; do not think that the more flowers bloom the better; thin out those deformed flowers and overly dense flowers;

3. Regulate spring shoots and remove summer shoots. Excessive spring shoot growth consumes too many nutrients and aggravates fruit drop, so spring shoots should be regulated after flower buds appear. Mainly remove the vigorous spring shoots (vegetative branches) on the upper part of the canopy, flower branches with more than 5 leaves, and late spring shoots; when summer shoots sprout new buds, remove the tender shoots multiple times until after fruit set is determined in mid-July, then begin to let shoots grow;

4. Pest and disease control: Common pests and diseases of pomelo trees include red and yellow spider mites, leaf roller moths and gummosis, etc. In summer, special attention should be paid to controlling these diseases and pests to prevent them from affecting fruit quality;

5. Spray plant hormones on the fruit trees at the appropriate time: such as kinetin, Zhibaosu, Jinyunda-120, etc.

Cultivation Techniques and Management Key Points for Rosa roxburghii (Chestnut Rose)

Fertilization

Apply quick-acting fertilizer 7-10 days before the spring, summer and autumn shoots sprout, focusing mainly on nitrogen fertilizer to promote shoot growth and leaf development. The amount of topdressing in the 2nd and 3rd years should increase year by year. Before the summer and autumn shoots sprout, apply 0.05-0.1 kg urea or 5 kg clear manure water per plant as topdressing. After the shoots and leaves of each season have sprouted and taken shape, spray monopotassium phosphate or other high-efficiency compound fertilizer on the leaves to promote shoot and leaf maturity. Starting from the outer edge of the planting hole, dig deep and expand the hole year by year combined with applying green manure, improve the soil, and use the orchard to support the orchard, ensuring normal growth of the fruit trees.

15-20 days before flowering, apply 0.1-0.2 kg urea per adult fruiting tree, or 15-20 kg clear manure water, to ensure normal growth and development of flower buds and leaf buds. After flower drop, promptly spray 0.5% urea solution to supplement the tree's nutrients and promote normal development of young fruit. From late June to early July, spray 0.5% monopotassium phosphate on the leaves of each plant and apply 0.25 kg urea or 30 kg manure water to the soil at the root of each plant. Depending on the tree's nutritional status, spray 0.5% urea solution on the leaves again, once every 7-10 days, for 2-3 consecutive times, to promote fruit expansion and improve yield and quality. Apply sufficient base fertilizer and improve the soil to lay the foundation for extending the full fruiting period and for high and stable yields in the coming year.

Diseases

The main pests and diseases of Rosa roxburghii include the pear fruit borer and peach fruit borer, rose long-tube aphid, rose white scale and powdery mildew, etc. To control pear fruit borer, peach fruit borer and aphids, you may choose 40% dimethoate emulsifiable concentrate 1500x solution, 80% dichlorvos 2000x solution, or fenvalerate 2000x solution; against rose white scale, spray 5-degree lime sulfur mixture in winter. For powdery mildew, use 70% thiophanate-methyl wettable powder 800-1000x solution, or spray 15% triadimefon wettable powder 1000-1500x solution. For pest and disease control in Rosa roxburghii, attention should be paid to autumn orchard cleaning, pruning out diseased and insect-damaged dead branches and diseased and insect-damaged fruits, plowing the soil, and spraying chemicals to sterilize and kill insects.

Irrigation

The root system of Rosa roxburghii is relatively shallow and its drought resistance is relatively weak, so water conservancy facility construction must be strengthened. In the dry season, divert water for irrigation or cover the tree basin to keep the soil moist.

Pruning

The buds of Rosa roxburghii have strong sprouting and branching ability. The tree crown is short and small with dense branches and leaves, and there is no obvious apical dominance or vertical dominance. Therefore, Rosa roxburghii should not be forcibly shaped and pruned; natural growth is preferable. When pruning, it is only appropriate to cut off diseased and insect-damaged branches, dead branches and aged branches. For groups of aged branches, retraction should be used to promote vigorous branches. For adult trees, efforts must be made to regulate the relationship between growth and fruiting, so that Rosa roxburghii can achieve the goal of stable and high yield.

Pepper Cultivation Techniques and Management Key Points

Pepper is an annual or limited perennial herbaceous plant of the genus Capsicum in the Solanaceae family. The fruit is usually conical or oblong, green when immature, and turns bright red, green or purple when mature, with red being the most common. The fruit of the pepper has a spicy taste because the fruit skin contains capsaicin, which can stimulate appetite. It is one of the most common vegetables or condiments in daily life. Below, the editor will introduce pepper cultivation techniques to everyone!

Pepper Growth Habits

The initial growth stage of pepper is the germination period. After sprouting and sowing, it generally emerges in about 5-8 days, the first true leaf appears in about 15 days, and up to the appearance of flower buds is the seedling stage. From the first flower cluster to the setting of the first pepper is the flowering period. From fruit set to uprooting is the fruiting period. The suitable temperature for pepper is between 15-34 degrees. The suitable temperature for seed germination is 25-30 degrees; germination requires 5-7 days. Below 15 degrees or above 35 degrees, the seeds will not germinate.

Pepper requires a relatively high temperature at the seedling stage, with 25-30 degrees during the day and 15-18 degrees at night being best. Seedlings are not tolerant of low temperatures, so attention should be paid to cold protection. If pepper is exposed to 35 degrees, it will cause flower and fruit drop.

Pepper has strict requirements for moisture conditions; it is neither drought-tolerant nor waterlogging-tolerant. It likes relatively dry air conditions.

Pepper Cultivation Techniques

1. Cultivation conditions

The temperature requirements of pepper are between those of tomato and eggplant. The suitable temperature for seed germination is 23-30°C; below 15°C it cannot germinate. Pepper seedlings require relatively high temperatures; when the temperature is low, growth is slow. In the early stage of flowering and fruiting, the suitable daytime temperature is 20-25°C and the nighttime temperature is 15-20°C. During the fruiting period, if the soil temperature is too high, especially with strong light directly hitting the ground, it is unfavorable to root growth and easily causes viral disease and sunscald.

2. Land preparation and base fertilizer

Pepper is not suitable for continuous cropping, nor can it be continuously cropped with crops of the same family such as eggplant, tomato, potato and tobacco. The plot for cultivating pepper should have good drainage, convenient irrigation and drainage, and require deep plowing. It is best to carry out winter plowing and leave the land fallow to freeze the soil, so as to improve the soil and eliminate overwintering pests and pathogen spores.

Before planting, prepare the land again. The topsoil should still remain in relatively large clods to allow air permeability and good drainage, which has a good effect on preventing flower drop, fruit drop and leaf drop. Changsha vegetable growers' requirements for pepper planting land are "deep ditches, high beds, breaking the old bottom, level soil, large clods, smooth water flow." The bed width is generally 1.3-1.7 m (including ditches), with 2-3 rows planted. There are also wide beds of 2.3-2.7 m with transverse planting on the bed. While making the beds, apply 50-80 loads of decomposed farmyard manure, 15 kg superphosphate, and 25 kg plant ash per mu as base fertilizer.

3. Sowing and seedling raising

① Seedbed selection: The seedbed should be selected on a plot facing north with its back to the south, high and dry with good drainage, convenient water source, and where solanaceous crops have not been planted.

② Seedbed preparation: It is best to dig the seedbed deeply and heat the soil in the dog days of summer, splash a layer of human and livestock manure on top, and after drying in the sun, cover with plastic film to prevent loss of fertilizer nutrients when it rains.

③ Sowing: Before sowing, water the seedbed soil thoroughly and rake it fine and level. The seedbed width is generally 1.5-1.7 m. Generally, seeds are not soaked for germination. Early-maturing varieties are generally sown in January, and late-maturing varieties are generally sown in February-March. For planting one mu, 75-120 g of seed is needed. After sowing, cover the seeds with fine soil mixed with old chaff ash or coal ash, with a thickness of about 2 cm, just enough to cover the seeds. Then water, and after the water is absorbed, cover with plastic film. Finally, use thin bamboo poles or bamboo strips to form a small arched frame, with a frame height of about 0.5 m, cover with plastic film on top, and compact the north side of the film with soil to help prevent wind. It is best to press both sides with bricks so that the film can be uncovered at any time for ventilation.

④ Seedbed management: After sowing and before emergence, generally no management is needed. Once emergence begins, immediately remove the plastic film, otherwise tall leggy seedlings will form. After emergence, uncover the film at 9 a.m. on sunny days and cover it again at 4 p.m. On cloudy and rainy days, ventilation should also be carried out as much as possible. If the seedbed soil turns white and the seedlings wilt, water is needed. Watering must be done between 9 a.m. and 1-2 p.m. Two hours after watering, check again. If some areas are still dry, supplement water so that the seedlings grow uniformly. Do not water on cloudy, rainy or freezing days; otherwise, due to excessive humidity and reduced bed temperature, diseases are likely to occur. In snowy weather, straw curtains can be added, and a layer of plastic film can be placed over the straw curtains. Electric lights can also be installed in the bed to help protect against cold and preserve seedlings.

⑤ Seedling transplanting: To make the seedlings sturdy and the root system well developed, when the seedlings have two true leaves, they need to be temporarily transplanted once, with a plant spacing of 6-10 cm and a row spacing of 12-15 cm. Water while transplanting to prevent the seedlings from wilting. The preparation, requirements and management of the transplanting bed are similar to those of the sowing bed.

4. Planting method

Pepper planting is best when the soil temperature is above 15°C. Planting too early, because the soil temperature is low, results in slow growth and flower drop, failing to achieve the purpose of early maturity. For planting distance, early-maturing varieties have a row spacing of 40-50 cm and a plant spacing of 26-33 cm, with 1-2 plants per hole; late-maturing varieties have a row spacing of 66-73 cm and a plant spacing of 50-60 cm, with 1 plant per hole. Choose a sunny afternoon for planting. On the morning of the same day, the seedbed needs to be watered to make it easier to pull up the seedlings.

5. Field management

① Cultivation and weeding: After planting and survival, carry out one shallow cultivation in time. When the plants begin to grow, carry out one focused cultivation. Before the plants close in, carry out another cultivation. Cultivation should be combined with weeding and earthing up.

② Fertilizer and water management: After planting, seize sunny days to apply seedling-promoting fertilizer. Each application should not be too much or too concentrated, otherwise it easily causes excessive vegetative growth and delays flowering and fruiting. After the first and second layers of fruit have set, apply more fertilizer to promote fruit growth. After the fruit begins to be harvested, the soil is even more required to have sufficient fertilizer and water so that the plants can grow and fruit normally. If, after watering and before the soil dries, heavy rain follows, leaf drop and plant death will be quite common, especially during the period from the beginning of summer to the beginning of autumn. Therefore, when irrigating, the irrigation time must be determined according to the weather forecast. The irrigation depth should preferably not exceed three-quarters of the ditch. It should be carried out at night or early morning, and should be irrigated and drained quickly.

③ Harvesting and seed saving: For fresh eating, most are harvested as green fruit, and red fruit can also be harvested. For dried chili peppers, red ripe fruit must be harvested, and harvesting must be timely, otherwise it will affect plant growth and fruiting.

For seed saving, use the method of combining plant selection with fruit selection, that is, select standard plants in the field according to variety characteristics and tag them as seed-saving plants. Harvest the first layer of fruit early for market, and keep 2-4 layers of fruit as seed fruit. When harvesting after the seed fruit turns red and ripe, further select fruits with the characteristics of this variety. Spread the harvested seed fruits in a cool place to after-ripen for 5-7 days, then cut them open to take out the seeds, dry them and store them.

Pepper Cultivation Management

Pepper likes warmth, water and fertilizer, but high temperatures easily cause disease, waterlogging easily kills seedlings, and too much fertilizer easily burns roots. Different stages of the entire growth period have different management requirements. After planting and before harvesting, promote roots and seedlings; from the beginning of harvest to the full fruiting period, promote seedlings and focus on fruit; after entering the high-temperature season, protect roots and seedlings to prevent decline and death of seedlings; in the late fruiting stage, continue to strengthen management to increase yield and income.

1. Management before harvest

During this period, the soil temperature is low and the root system is weak, so it is necessary to promote more and control less. That is, water lightly, topdress early, cultivate frequently, and carry out light seedling restraint. Water lightly for seedling recovery, and a small amount of manure water can be applied along with it. After watering, cultivate in time to increase temperature and preserve moisture, and promote root development. Seedling restraint should not be too long, about 10 days or so. Light watering and light seedling restraint can be used to regulate the relationship between roots and seedlings. After seedling restraint ends, water and topdress in time to increase early yield. Topdressing should mainly be nitrogen fertilizer, with some phosphorus and potassium fertilizer applied together, to promote sturdy seedlings and prevent flower drop. Promptly remove the lateral branches on the main stem below the first flower.

2. Management from the beginning of harvest to the full fruiting period

At this stage, the temperature gradually rises, rainfall gradually increases, and pests and diseases occur one after another. This is the key period determining yield. To prevent premature aging, harvest the first pepper early, water in time, and keep the soil moist regularly to promote seedlings and focus on fruit, striving to close the rows in the high-temperature season. After entering the full fruiting period, before the rows close, earth up to protect the roots, and combine earthing up with topdressing.

3. Management during the high-temperature season and afterward

The high-temperature rainy season easily induces viral disease, with severe flower and fruit drop and sometimes large-scale leaf drop. Therefore, in hot and dry years, irrigation must be done at the beginning of the drought period, not at the end, and the soil must always be kept moist to inhibit the occurrence and development of viral disease. After rain, apply a small amount of chemical fertilizer to protect the seedlings, and also irrigate in time to prevent drought after the rainy season from forming a peak of viral disease. In the high-temperature season, irrigation should be done in the morning and evening. During the full flowering period, spray 800-1000x chlormequat 3-4 times, which has a good effect on preserving flowers and increasing yield.

4. Management in the late fruit-shrinking stage

After the high-temperature rainy season, when the temperature turns cooler, the green pepper plants return to normal growth. Management must be strengthened to promote the formation of a second full fruiting period and increase late-stage yield. Water in time, and combine watering with topdressing quick-acting fertilizer to supplement the soil's nutrient deficiencies.

Key Management Points to Note

1. The seedling age of spring pepper is about 110 days, and some can reach more than 150 days. In northern regions, planting usually can only be done in mid-April or late May. Pepper itself has high and stable yield, but the yield reduction in some places is caused by variety degeneration, poor disease resistance, and severe diseases. The planting plot should be selected as spring white land where solanaceous fruit vegetables, cucumber and tobacco have not been planted in recent years. Land that has just harvested overwintering spinach is also not good. About 7 days before planting, apply 5000 kg farmyard manure, 75 kg superphosphate, and 30 kg ammonium bicarbonate per mu as base fertilizer, open furrows at a row spacing of 70 cm, level, form ridges, cover with film, and wait for planting. Planting can be done at a plant spacing of 30 cm, with seedlings placed alternately in two adjacent rows, one plant per hole. 2500-3000 holes per 667 sq m.

2. From planting to the fruiting stage is the early stage of pepper field management. Management should promote roots, seedlings and plant development. Attention should be paid to watering and cultivation during this period. 15 days after planting, apply 10 kg phosphate fertilizer and 5 kg urea, and combine with cultivation and earthing up to a height of 10-13 cm to protect the root system and prevent lodging. After entering the full fruiting period, the focus of management is to strengthen seedlings and promote fruit. Promptly remove the first pepper to prevent fruit drop from causing decline in growth. Combine watering and fertilization, apply 20 kg phosphate fertilizer and 5 kg urea per 667 sq m, and earth up the roots again. Pay attention to drainage and waterlogging prevention. Combine spraying foliar fertilizer and hormones to supplement nutrients and prevent viruses.

3. Pepper is sensitive to many herbicides during its growth period, especially 2,4-D emulsifiable concentrate. Improper spraying of pesticides will cause serious phytotoxicity to pepper.

Pepper Disease Control

1. Bacterial wilt

[Disease characteristics] When the plant becomes diseased, the top leaves of the diseased plant wilt during the day and recover on cloudy days or in the morning and evening. After 2-3 days, the leaves remain green but the whole plant wilts. Cut open the diseased stem; the vascular bundles are brown. Soak the cut section in water, and white turbid bacterial fluid flows out from the cut.

[Occurrence pattern] Pepper bacterial wilt is a bacterial disease. It occurs severely when the soil temperature reaches 20°C-25°C, the air temperature reaches 30°C-37°C, and the soil moisture content reaches above 25%. When heavy rain suddenly clears, the temperature rises rapidly, humidity is high, and transpiration is large, the pathogen is highly active, diseased plants increase, and damage is severe. The pathogen develops suitably when the soil pH is 6.6.

[Control methods] ① Select disease-resistant varieties. ② Adjust soil pH, applying 50-100 kg lime per mu. ③ Implement crop rotation to prevent continuous cropping or repeated cropping. ④ Inspect in time. If diseased plants are found, immediately pull them out and burn them, and scatter lime powder in the holes. In the early stage of the disease, 100-200 PPM agricultural streptomycin or one packet of kasugamycin can be mixed with 150 jin of water to drench the soil, with continuous control 3 times, and root irrigation once every 10-15 days for 2-3 consecutive times.

2. Phytophthora blight

[Disease characteristics] The disease can occur throughout the entire growth cycle. When infected at the seedling stage, it mostly occurs at the base of the stem. When the seedling stage is affected, the stem base becomes dark green, water-soaked, soft-rotted or damping-off, which is seedling damping-off. In some cases, the stem base becomes dark brown and the seedlings wilt and die. When leaves are infected, the lesions are round or nearly round, 2-3 cm in diameter, with yellow-green edges and dark brown centers. When fruit is infected, it starts at the stalk. Initially dark green water-soaked spots appear, quickly turning brown and soft-rotted. Under high humidity, white mold grows on the surface, namely the pathogen's sporangiophores and sporangia. After drying, dark brown streaks form, and the branches and leaves above the diseased part quickly wilt.

[Occurrence pattern] The pathogen overwinters in the soil or diseased tissues as mycelium and oospores. Oospores spread through splashing rain and irrigation water. The optimum temperature for pathogen development is 23°C-31°C. High temperature and high humidity favor the occurrence of the disease.

[Control methods] ① If pepper phytophthora blight is soil-borne, pesticide root irrigation must be used for control. ② The key control time is mid-to-late June, during the full flowering and fruiting period of pepper, generally within 1-2 days after the first watering for root irrigation. ③ Effective pesticides are 25% metalaxyl or 58% metalaxyl-mancozeb, used at a concentration of 500x solution for root irrigation, with 0.3-0.4 jin per hole giving the best effect.

3. Powdery mildew

[Disease characteristics] Pepper powdery mildew is caused by the ascomycete fungus Leveillula taurica. Leaves, both old and young, can be infected. In the field, it mainly spreads through airflow. Under slightly dry conditions, the disease is prone to epidemic. On the upper surface of diseased leaves, small chlorotic yellow spots first appear, then expand into chlorotic yellow mottling with indistinct edges. On the underside of the diseased part, white powdery material is produced. In severe cases, lesions are densely distributed, causing the entire leaf to turn yellow and a large number to fall off, forming bare stems, seriously affecting yield and quality.

[Control methods] ① When planting, choose varieties with relatively good disease resistance and dress seeds with New High Lipid Film (which can repel underground pests and diseases, isolate virus infection, not affect germination and imbibition, strengthen respiration, and increase seed germination rate). ② Before planting, deeply plow the soil and spray 800x New High Lipid Film solution to sterilize and disinfect, preserve temperature and moisture. ③ During each growth period of pepper, spray Chili Stalk Strengthener at the appropriate time to enhance internal nutrient transport and improve pepper's resistance to external pathogens. ④ In the early stage of the disease, spray 1000x Duoyangqing solution plus 3000x DuPont Fuxing solution and add New High Lipid Film; the effect is especially good.