Planting techniques of okra

Okra, also known as okra, sheep's horn bean, sheep's horn pepper, is an annual herb of the family Malvaceae, which collects tender pods for food, and tender flowers and leaves are also edible. It originated in Africa and then entered the Americas. Now the largest producer of okra is there in the southern United States, and Americans have given it a more memorable name, "Plant Viagra." China's Jiangsu, Shandong, Guangxi, Chongqing, Anhui, Heilongjiang, Shaanxi and other places are now planted, seeds such as Jiangsu Changjing Garden, Guangdong and other places have.

Planting conditions

Okra likes warmth, is afraid of cold, and has strong heat resistance. The growth stopped below 8 ℃, and when the air temperature was 13 ℃ and the ground temperature was about 15 ℃, the seeds could germinate. However, the optimum temperature for seed germination and growth period was 25-30 ℃. When the monthly average temperature is lower than 17 ℃, the flowering and fruiting is affected, while when the night temperature is below 14 ℃, the growth is slow, the plant is short, the leaf is narrow, the flowering is less, and the flower drop is more. 26-28 ℃ has many blossoms at suitable temperature, high fruit setting rate, rapid fruit development, high yield and good quality.

1. Moisture

Okra is resistant to drought and moisture, but not to waterlogging. The excessive soil moisture during the germination period is easy to induce seedling blight. During the fruiting period, the soil should always be kept moist because of the drought, poor plant growth and poor quality.

2. Lighting

Okra is particularly sensitive to light conditions, like strong light, requires a long time of light, sufficient light. Sunny land should be selected, ventilation should be strengthened, and reasonable close planting should be paid attention to so as not to shade each other and affect ventilation and light transmission.

3. Soil

Nutritious okra has wide adaptability to soil and does not choose soil fertility, but it is more suitable for loam or sandy loam with deep soil layer, loose and fertile soil and good drainage. Nitrogen is the main fertilizer in the early stage of growth, and more phosphorus and potassium fertilizer is needed in the middle and later stage. However, if there is too much nitrogen fertilizer, the plant is easy to grow, the flowering and fruiting is delayed, and the node position of fruit setting is increased; insufficient nitrogen fertilizer and poor plant growth affect flowering and fruit setting.

Growth cycle

1. Germination period

When sowing to 2 cotyledons, the cotyledon flattened is the germination period, which takes about 10 to 15 days. Sowing at 25: 30 ℃ and sowing for 4: 5 days, the soil can be germinated. It usually takes about 7 days for direct seeding seedlings to be unearthed in the open field, and plastic film mulching can produce seedlings 2-4 days in advance.

2. Seedling stage

It takes about 40 to 45 days from 2 cotyledons to the first flower blooming. After the general cotyledons were fully expanded, the first true leaf unfolded after 15-25 days. After that, a true leaf occurs every 2-4 days, in which the first two true leaves are round. The growth is slow in the seedling stage, especially when the ground temperature is too low.

3. Blossom and fruit

It takes about 85 to 120 days from the beginning of flower to the end of harvest. It takes 50-55 days after emergence, and the first flower blooms immediately. The first and second flowers take a little longer from flowering to harvest. Later, with the increase of temperature, the harvest time shortened. It is usually harvested for the first time about 70 days after sowing. It can be harvested 4 days after flowering at a temperature of 28 ℃ in the day and 18 ℃ in the night. Okra grows faster and grows stronger after flowering and fruiting, especially at high temperature. It spreads a true leaf every 3 days in July and 4-5 days in September.

Cultivation season

Okra likes warmth and is afraid of frost. the whole growth period should be arranged in the frost-free period, and the flowering and fruiting period should be in the warm and humid season. Cultivation in the open field, sowing in April to June in the north and south, and harvest in July to October. The seeds in North China are usually sown from mid-late April to May. Seedlings are raised in solar greenhouses and plastic greenhouses commonly used in cold areas in the north, and then planted in the field after frost in early spring and evening.

Prepare the land for border formation

Okra avoid continuous cropping, can not be mixed with fruits and vegetables, so as to avoid the occurrence of root-knot nematodes. It is best to choose root vegetables, leaf vegetables and so on as the previous stubble. The soil layer is deep, fertile and loose, and it is more suitable to conserve water and fertilizer. After harvest before winter, ploughing deeply in time, 75000 kg of rotten barnyard manure and 300kg of nitrogen, phosphorus and potassium compound fertilizer were applied per hectare. Open field cultivation: row spacing 40 cm, plant spacing 12 cm, border ditch width 50 cm. If planted in a single row at the edge of the field, roadside and riverside, the plant spacing is 12 cm, 3 plants per hole, ventilated and transparent, easy to manage.

Sowing and raising seedlings

Soak the seeds in 20-25 ℃ warm water for 12 hours before sowing, then dry them, germinate at 25-30 ℃ for 48 hours, wait for half of the seeds to be white, dig holes according to row spacing 40 cm and plant spacing 12 cm, first pour enough bottom water, sow 2-3 seeds per hole, cover soil 2-3 cm, and plant about 6000 holes per mu.

1. Live broadcast method. Multi-line live broadcast of okra. Soak the seeds for 12 hours before sowing, and then put them under 25: 30 ℃ to promote germination. About 24 hours later, the seeds begin to sprout, and the seeds are sown when 60% to 70% of the seeds are "broken." It is appropriate to sow in holes, with 3 plants in each hole and a depth of 2 cm to 3 cm. All localities should sow seeds at the right time after the final frost period, watering first, then sowing, and then covering about 2 cm of soil.

2. Seedling transplanting method. In the northern region, more seedlings were sown and raised in sunny beds and solar greenhouses in the first and middle of March. The bed soil is made of 6 parts of garden soil, 3 parts of mature organic fertilizer and 1 part of fine sand. Soak seeds to promote germination before sowing, flatten the seedling bed, sow on demand according to the row spacing of 10 cm, and cover the soil with a thickness of about 2 cm. The bed soil temperature should be kept at 25 ℃ after sowing and germinated and unearthed in 4-5 days. The seedling age was 30-40 days and the seedlings were colonized with 2-3 true leaves. It is best to adopt measures such as plastic bowls, nutritious soil blocks and other root protection measures to cultivate strong seedlings of the right age. Planting in the open field is not suitable for seedling cultivation, the growing wind or Rain Water is too large and easy to lodge, although direct seeding uses a large amount of seeds, but the plant root system is deep in the soil, not easy to lodge.

Field management

1. Seedling. When the heart is broken, the seedlings are broken for the first time, and the weak seedlings are removed from time to time. When there are 3 true leaves for the second time, strong seedlings are selected. 3The seedlings were fixed when there were 4 true leaves, and 1 plant was left in each hole.

2. Weeding and soil cultivation in middle ploughing. After the seedlings are unearthed or planted, the temperature is low, so they should be ploughed twice in a row to increase the ground temperature and promote slow seedling. The first flower should be ploughed before blooming in order to squat seedlings moderately to facilitate root development. After flowering and fruiting, the plant growth is accelerated. After each watering and topdressing, the plant should be intertilled, and the soil should be cultivated before closing ridges to prevent the plant from lodging. Summer rainstorm windy areas, it is best to choose about 1 meter bamboo pole, or branches inserted near the plant to prevent lodging.

3. Watering and fertilization

① watering: okra requires higher air and soil moisture during its growth. Artificial sprinkler irrigation should be done in the morning and evening when there is a shortage of water within 20 days after sowing. After the seedlings are slightly larger, mechanical sprinkler irrigation or furrow irrigation can be used. The summer season is in the peak harvest season of okra, with large water demand and high surface temperature, so it should be watered before 9 o'clock in the morning and after sunset in the afternoon to avoid root damage under high temperature. Pay attention to drainage in the rainy season to prevent dead seedlings. The whole growing period is to keep the soil moist.

② topdressing: on the basis of sufficient base fertilizer, proper topdressing should be applied, not partial application of nitrogen fertilizer. The first time was Qimiao fertilizer, which was carried out after emergence, applying urea 90-120 kg per hectare. The second time is to raise seedling fertilizer, fixed seedlings or planting after opening ditches to withdraw application, per hectare application of compound fertilizer 225,300kg. Re-application of fertilizer during the flowering and fruiting period, 30000-45000 kg of human manure, or 300kg-450kg of nitrogen, phosphorus and potassium compound fertilizer. In the middle and later stage of growth, a small amount of topdressing should be applied for many times to prevent plant premature senescence.

4. Plant adjustment. Okra plants grow vigorously under normal conditions, the main and lateral branches are stout, the leaves are hypertrophic, and the flowering and fruiting are often delayed. Twisting branches can be adopted, that is, the petiole is twisted into a curved sag to control vegetative growth. In the middle and later stage of growth, the timely removal of the old leaves below the tender fruit can not only improve the ventilation and light transmission conditions, reduce nutrient consumption, but also prevent the spread of diseases and insect pests. Picking the heart of the young fruit harvester at the right time can promote the lateral branch fruit and increase the early yield.

Harvest

Okra takes about 55 days from sowing to the formation of the first tender fruit. After that, the whole harvest period is as long as 90,120 days, and the whole growth period can reach about 150 days, or even longer. The picking standard of okra commercial fresh fruit is that the fruit is 8cm long, the fruit appearance is bright green, and the seeds in the fruit are not aging. If the harvest is not timely, the meat quality is aging, the fiber is increased, and the edible value of the commodity is greatly reduced. In general, after the first fruit is harvested, it is harvested every 2-4 days at the initial stage, and the harvest interval is shortened with the increase of temperature.

During the full fruit period in August, it is harvested every day or every other day. After September, the temperature dropped and harvested once every 3-4 days. When harvesting, it is appropriate to use scissors and put on gloves to avoid stabbing the skin with bristles or tumors on stems, leaves and fruits. Wash them with soapy water or roast lightly on fire to reduce the pain and itching. Usually, the tender fruit is harvested 4 days after flower fade, and the quality is the best. The yield per mu is about 2000-3000 kg.

Pest control

1. Epidemic disease

Okra can be infected at seedling stage and adult stage. When the seedlings grew 20 years old, the disease spot spread from the leaves to the main stem, making the stem thinner and faded, until the whole plant wilted or knocked down. The infection of leaves usually starts from the lower leaf tip or leaf green of the plant, and it is dark green water-stained anplastic spot at the beginning of the disease, and turns brown after enlargement. Prevention and treatment: at the initial stage of the disease, 72% manganese zinc, frost urea WP (Kelu) 500x solution or 69% Anke manganese zinc WP900 solution or 64% antivirus alum WP400 solution or 58% metalaxyl, manganese zinc WP500 multiple solution was sprayed once every 7 to 10 days, prevention and treatment for 3 times.

2. Virus disease

Okra virus disease is the main disease in okra production, which is more serious in adult stage than in seedling stage. After the plant was infected, the whole plant was damaged, especially the delicate leaves at the top, which showed mosaic or brown markings. Early infection, short plants, little or no fruit. Prevention and control methods: do not leave seeds from the diseased field, select disease-resistant varieties, use 5% bacteriorubicin WP400~500 times liquid or 20% virus AWP400 times liquid or 15% plant disease Ling 1000 times solution or 83% resistance enhancers for 3 times, once every 7 to 10 days.

3. Poison caterpillar

Okra is mainly harmful to the seedling stage. It often feeds on the mesophyll after emergence and retains the vein when it is serious. Prevention and treatment: spray with 10% EC1500 solution or 5% strong SC1500 solution or avermectin EC+ fenvalerate EC3000 solution.

4. Liriomyza sativae

Damage can occur throughout the growing period of okra, mainly damage leaves, can be controlled with 1.8% Avermectin EC (avermectin) 5000 times liquid or 52.25% Nongdile EC1000 solution or 48% Lexben EC1000 solution or 5% Regent SC800 solution.

5. Aphids

Okra can occur in the whole growing period, and the damage is more severe in the adult stage. 3000-fold solution can be used, such as 10% imidacloprid pesticides, 10% aphid lice net 10% and so on.

6. Ants

Ants often gather on the flower apparatus to do harm after okra blossoms. Control with 48% EC1000 double solution spray or 5% Regent EC1500 double solution spray or sprinkle with 0.3% Regent solution mixed with sawdust on the place where the ants come out. Okra harvest interval is short, the chemicals used must choose suitable pesticides for pollution-free vegetables, spray as far as possible not to spray on the flower or tender fruit.

7. Ground tiger

The ground tiger goes out at night and often bites off the main stem at the seedling stage, resulting in seedling breakage. Commonly used sugar and vinegar lure capture or early morning digging capture, can also be killed with special pesticides.