Watermelon is the main summer summer fruit. The flesh is crisp and tender, sweet and juicy, rich in mineral salts and multivitamins. It is the largest fruit sold in summer and autumn in my country. In order to improve the yield and quality, the watermelon cultivation techniques are introduced as follows:
1. Biological characteristics
1. Morphological characteristics
(1) Root The root of watermelon is a deep root system, the main root is more than 1 meter deep, and the lateral root can extend up to 4-6 meters. The root regeneration ability is weak, and it is not easy to recover after injury. Live broadcast is often used in production. If seedlings are transplanted, care must be taken to protect the roots.
(2) Stems and leaves Watermelon stems are also known as vines. The main vines grow upright before 5-6 leaves, and when they continue to grow to a certain length beyond 30 cm, they cannot support their own weight due to the underdeveloped mechanical structure, and they crawl on the ground. grow. The branching ability of the stem is very strong, and it can germinate 3 to 4 side branches, but the side branches issued from the 3-5 leaf axils of the main vine are relatively strong. Adventitious roots are easily formed on the stem nodes of watermelon. The method of pressing vines can promote the formation of adventitious roots, increase the absorption area, fix the plants, and prevent rolling. The leaves are alternate, with deep-lobed, shallow-lobed and entire types.
(3) Flowers, fruits and seeds Watermelon flowers are small yellow, monoecious and dioecious, solitary in the leaf axils. Early-maturing varieties have their first female flowers at the sixth and seventh nodes of the main vine, and mid- and late-maturing varieties have their first female flowers after the tenth node. The number of internodes in female flowers is 7-9. A few bisexual flowers can appear in the peak flowering period, and the flowers open in the morning and close in the afternoon.
The fruit is oval, spherical, dark green, light green, or with black-green stripes or markings. The flesh of melon is red, yellow, and white. The seeds are black, white, or red. Watermelon can also be divided into large-seed watermelon, small-seed watermelon and seedless watermelon according to the size of its seeds. 25 grams.
2. Fertility cycle
The whole growth period can be divided into four periods: germination period, seedling period, vine-drawing period and fruiting period.
(1) Germination stage: The germination stage is from seed germination to cotyledon unfolding, and true leaves are revealed. After the seedlings are unearthed, prevent leggy growth to promote the development of roots and leaves.
(2) Seedling stage The seedling stage is from the emergence of true leaves to 5 to 6 leaves. During this period, the growth amount is small, and good conditions should be given for cultivation to promote the root system and organ differentiation of seedlings.
(3) The vine-drawing stage The vine-drawing stage starts from 5-6 leaves and the female flowers at the melon node open. During this period, the growth rate is fast and the growth amount is large. Cultivation to promote the growth of stems and leaves, the formation of certain nutrients. At the same time, it is necessary to control the leggy length to ensure the formation of the flower vessel.
(3) Fruiting period: from the opening of the female flower at the flower node until the fruit begins to grow vigorously. It can also be divided into three periods: fruit setting period, fruit growth period, and fleshy period.
The fruit setting period is from the opening of the female flowers of the Liumelon Festival until the fruit begins to grow vigorously. Photosynthetic products begin to enter the fruit. Cultivation mainly adjusts the balance of vegetative growth and fruit development to ensure that the melon is sitting.
The vigorous fruit growth period is from the rapid growth of the fruit until the size of the fruit is basically fixed. During this period, the fruit grows a lot and absorbs the most nutrients, which is the key period for the formation of yield. Cultivation should be given large fertilizer, water, and promote the rapid growth of fruit.
The pulping stage is basically fixed from the size of the fruit to the maturity stage. During this period, the sugar is rapidly converted, and the appearance has the inherent color of the variety. Cultivation should prevent premature aging of stems and leaves to ensure yield and quality.
3. Requirements for environmental conditions
(1) Temperature Watermelon likes a warm, dry climate and is not cold-resistant. The optimum temperature for growth and development is 24-30 degrees, the optimum temperature for root growth and development is 30-32 degrees, and the lowest temperature for root hairs is 14 degrees. Watermelon needs a large temperature difference between day and night in the process of growth and development, and a large temperature difference between day and night can cultivate high-quality watermelon.
(2) Moisture Watermelon is drought tolerant and intolerant of humidity. When it is rainy for a long time, the humidity is too high, which makes it susceptible to diseases, low yield and poor quality.
(3) Lighting Watermelon likes light. Under the conditions of sufficient sunlight, the yield is high and the quality is good.
(4) Nutrients Watermelon has a long growth period and high yield, so it needs a lot of nutrients. Each production of 100 kilograms of watermelon needs to absorb about 0.19 kilograms of nitrogen, 0.092 kilograms of phosphorus, and 0.136 kilograms of potassium. However, there are obvious differences in the absorption of nutrients in different growth stages, accounting for 0.01% in the germination stage, 0.54% in the seedling stage, and 14.6% in the vine-sucking stage. Therefore, with the growth of the plant, the amount of fertilizer required for watermelon gradually increases, and reaches the maximum value when the fruit grows vigorously.
(5) Soil Watermelon has strong adaptability, and sandy soil with loose soil, deep soil layer and good drainage is the best. Like weak acid, PH5-7.
The suitable time for sowing
Watermelon open field cultivation is cultivation without protective equipment. Generally, when the local final frost has passed and the ground temperature is stable at about 15 ℃, it is the suitable time for open field sowing. The best time for sowing should also be determined according to conditions such as varieties, cultivation seasons, cultivation methods and consumption seasons. Generally, seedlings are sown in mid-late March, planted in mid- and late-April, and harvested and marketed in late June; autumn watermelons are sown in early and mid-July, and harvested and marketed in late September.
3. Soil preparation and application of basal fertilizer
To cultivate watermelon, choose a plot with loose soil, deep soil layer, fertile soil, good drainage, sufficient light, and when the sun is in the west. Otherwise, fusarium wilt is serious; the previous crops are rice, corn and other gramineous crops as the best, followed by potato, cabbage and other vegetable crops, but watermelon, which was previously used as a melon vegetable, is seriously diseased and should not be selected.
The melon fields must be ploughed deeply, and it is best to dig the ground in winter. In the plots that have been deeply ploughed or have deep ploughing foundations, open drainage ditches around, and open the ditch (ditch width 0.5 meters) according to the row spacing of 2.4-3.0 meters. Apply 2500-3000 kg of farmyard manure, 15-20 kg of phosphate fertilizer, 20-25 kg of 45% compound fertilizer, 2 kg of borax, and 1 kg of zinc fertilizer. In order to prevent underground pests, a small amount of crystal *** can be mixed in the base fertilizer. Cover the base fertilizer ditch, and form a melon ridge and finally cover it with plastic film, waiting for sowing or transplanting. When opening the carriage, it should be noted that the carriage is perpendicular to the direction of the spring and summer winds, and the basal fertilizer is applied on the side of the carriage where the wind blows first, so as to facilitate the melon vines and the wind direction after planting.
4. Seed soaking and germination
1. Before soaking the seeds, dry the seeds for 1 day, soak the sun-dried seeds with warm water (about 30°C) that is not hot to the hands for 6-8 hours, then remove the seeds and wrap them with a towel or coarse cloth and rub the seed skins. In order to prevent fusarium wilt, the mucous membrane on the top is soaked with thiophanate-methyl for another 4 hours. Generally, the soaking time is required to reach 12 hours. After the seed coat is softened, it can be taken out and rinsed with clean water for germination.
2. Germination Put the soaked seeds flat on a wet towel, cover the seeds with a layer of wet towel, and place them in an environment of 30-35 degrees for germination. After 72 hours, the seeds are basically flushed, and 85-90% of germination can be sown. .
5. Sowing or transplanting
1. Direct germination and direct seeding. Open a shallow trench or hole with a depth of 8 cm to 10 cm on the melon ridge near the base fertilizer application, with a plant spacing of 45-50 cm, and sow 1-2 seeds for germination in each hole (after watering once in drought) Covering soil is 2 cm to 3 cm, and the seedlings can emerge after 2 to 3 days for germination and direct seeding; generally, 150 grams to 200 grams of seeds are used per mu.
2. Seedlings and transplanting The seedlings are 30-35 days old, and the melon seedlings are transplanted with 3 leaves and 1 heart. The plant spacing is 45-50 cm, and about 450-500 trees are planted per mu. After transplanting, the root water is poured.
6. Field Management
1. Intertillage and drainage intertillage are started after sowing seedlings or planting and returning seedlings. Generally, thinning, loosening soil, and cultivating soil are carried out in combination. Watering should be less in the seedling stage, and attention should be paid to "squatting seedlings" to facilitate root growth; When the centimeter is chasing a heavy fertilizer, then cultivate the soil. Watermelon has large fruit, high yield, and large water demand. Pay attention to irrigation in dry land cultivation, and drainage work is particularly important in paddy field cultivation. It is emphasized that the drainage ditches around the furrows and fields should be connected with each other, and there should be no stagnant water in the fields after the rain, which is the basis for ensuring high and stable watermelon production. Stop irrigation 6-8 days before fruit ripening to promote sugar conversion and increase sweetness.
2. Topdressing The basic principles of topdressing melon fields are: lightly apply seedling fertilizer, first promote and then control, skillfully apply vine fertilizer, and re-apply bulk melon fertilizer after sitting on young fruits.
(1) Seedling-promoting fertilizer Seedling-promoting fertilizer is generally topdressed within a week after transplanting melon seedlings or at the 4-5 leaf stage of live seedlings, and a small amount of quick-acting fertilizer is topdressed when the base fertilizer is insufficient or the fertilizer effect of the base fertilizer has not been exerted. Generally, 8-10 grams of urea (or 20 grams of ammonium sulfate) is applied to each plant, and the soil is covered after ditching and fertilizing.
(2) The vine-inducing fertilizer can be carried out before and after spreading the vines. Generally, when the melon seedlings grow to 40-60 cm, apply 10-12 kg of urea, 8 kg of superphosphate, and 13 kg of potassium sulfate per mu, or use 45 kg per mu. % potassium sulfate type ternary compound fertilizer 18-22 kg, ditch 25-30 cm from the root of the melon or apply in the middle of two plants, and the depth of the ditch is 10-15 cm. After application, cover the soil with water to promote the absorption of fertilizer.
(3) Expansion melon fertilizer Expansion period is the period when watermelon needs the largest amount of fertilizer in its life. When watermelon eggs are large, the root system is covered with the whole border. Many melon farmers will apply expanded melon fertilizer at this time. The root system around the fertilization point is burnt out, which is also not conducive to the rapid decomposition and transformation of fertilizers, which is very different from the characteristics of watermelon expansion, which are large in size, water, and quick-acting. . When the watermelon eggs are large, the surrounding area is about 30-45 cm away from the base of the melon root (the side where the melon vines are mainly stretched), and the manure water is added with compound fertilizer and urea. Kg and 5 kg of potassium sulfate are dissolved and applied with water. The concentration of the puffed melon fertilizer should be light, and the fertilizer should be adjusted with water, so that the fertilizer can play a role in a short period of time, especially when the soil is relatively dry, the immediate effect of puffing melon can be obtained. In the later stage, foliar spraying fertilizer is used, and 0.4% potassium dihydrogen phosphate solution is used to spray once every 7-10 days, and spray 2-3 times in total.
3. Pruning Watermelon with luxuriant vines and leaves, if the vines are allowed to grow and overlap each other, it will not only affect the dense planting, but also delay the fruiting. Watermelon pruning methods generally include single vine, double vine and triple vine. Single-vine pruning leaves only one vine per plant. All the remaining lateral vines are removed, the method is simple, the number of plants per unit area is more and the number of melons is more, but the leaves per plant are few, the fruit is not easy to grow, and the yield and quality are low. When the main vine grows to more than 30 cm, the double-vine or triple-vine pruning generally leaves a strong lateral vine at the base, and the three-vine pruning leaves two strong lateral vines as secondary vines or preparations. vines, and the rest of the lateral vines are removed; double-vine pruning is mostly used in production. When pruning watermelon, one should pay attention to pruning at the right time. Generally, it starts when the main vine is 40-50 cm long and the lateral vine is about 15 cm, and then every 3-5 days; secondly, no matter which pruning method is used, it is required to be carefully carried out before fruit setting, and generally no pruning after fruit setting, so as to make There are more branches and leaves to provide nutrients for fruit growth. When the fruit begins to expand rapidly, in order to prevent excessive vegetative growth, topping can be carried out.
4. When the vines are 30 cm long, the vines should be trimmed to make them evenly distributed, and the vines should be pressed with soil blocks on the nodes to promote the formation of adventitious roots, fix the leaf vines, and prevent mutual shading and damage to the roots and leaves from being blown by the wind. Press once every 5 to 6 knots until the vine leaves are covered with the border. There are two kinds of pressing methods: open pressing and dark pressing. In rainy areas, the soil humidity is high. In order to prevent rotten vines, it is not necessary to bury the melons and vines in the soil. Only the soil blocks are pressed on the nodes, and the internodes are still exposed to the ground, which is called "open pressure". In order to promote the occurrence of adventitious roots in arid areas with little rainfall, the melons and vines should be straightened and buried in the soil, which is called "dark pressure". In order to prevent breaking the crisp and tender melon vines, pruning and pressing the vines should be carried out in the afternoon. No matter which pressing method is used, it should be determined according to the growth of the plant. Those with strong growth should take heavy and diligent pressure, and those with weak growth should be lightly and less stressed. Generally, it is pressed once every 5-6 sections, with two pressures on the front and back of the melon. Leave 2-3 leaves before and after the female flower of the melon without pressing, to prevent the melon from stagnant water and rotten melon, or the melon will be restrained when it grows.
5. Artificially assisted pollination Watermelon is a cross-pollinated crop that relies on insects as a medium. In rainy weather or when insects are less active, it will affect the spread of pollen and make it difficult to set fruit. In order to improve the fruit setting rate and achieve the ideal node position for fruit setting and melon retention, artificial assisted pollination should be carried out.
(1) When the female flower is selected for pollination, the well-developed female flower on the main vine and the lateral vine should be selected. Its flower bud is thick, the ovary is large, the shape is normal, the color is green and shiny, and it is easy to set fruit after pollination and grow into a high-quality melon . The female flowers on the side vines are reserved for melons.
(2) Pollination time The flowers of watermelon begin to loosen at 5-6 in the morning, and the physiological activity is most vigorous at 8-10, which is the best time for pollination. The pollination time on cloudy days was delayed to 9-11 o'clock due to late flowering.
(3) Pollination method Use fresh male flowers that open on the same day and are loose powder, pinch the petals with your hands toward the stalk, then align the stamens of the male flowers with the stigma of the female flowers, and dip them lightly for a few times. A male flower can give 2 to 3 female flowers.
6. Keep the melon generally leave the second and third female flowers to bear the melon. Early-maturing varieties can reserve the first to third female flowers. After the melon is seated, choose the best melon in the order of "two, one, and three". For mid-late maturing varieties, the second to fourth female flowers can be reserved. After the melon is seated, select one melon in the order of "third, second, and fourth". If the melons on the main vine are not seated, keep the melons on the side vines in this order. It is advisable to keep 1 melon per plant.
7. Watermelon fruit care In the stage of watermelon flowering, fruit setting and fruit development, careful fruit care is also a key link to improve watermelon yield and quality. Nursing measures include protecting melons, padding melons, turning melons, vertical melons, drying melons and covering melons.
From the opening of female flowers to before and after fruit setting, the ovary and the epidermis of young melons are very delicate and vulnerable to wind, insect bites and mechanical damage. At this time, paper bags, plastic bags, etc. are used to cover the young melons, which is called protecting melons. When the fruit grows to 1 to 1.5 kg, the clods under the melon are broken and leveled, and the grass or fine sand is placed on it, that is, the melon is placed. Turning the melon means constantly changing the position of the fruit on the ground, so that the melon surface is evenly exposed to light, the skin color is the same, and the melon flesh maturity is uniform. Turning the melon is generally carried out in the middle and late stages of the puffed melon. It is turned once every 5 to 6 days, and it can be turned 2 to 3 times. The angle should not be too large, and the ground should be exposed to avoid spraining and twisting the handle of the melon. Each time the melon should be turned in the same direction. A few days before the watermelon is ripe and harvested, the watermelon can be erected to ensure that the fruit is round and the skin is well-colored. Otherwise, the sun will not be visible on the ground, and it will be yellow-white, which not only affects the appearance of the fruit, but also the thickness of the skin is uneven. , fruity, poor quality.
The sun and cover of the melon is based on the principle of "sun in hours and cover when it is ripe". In the immature green peel, there is a lot of chlorophyll, and the photosynthetic products produced are directly lost to the fruit to promote the accumulation of sugar, so it needs to be exposed to the sun when it is young. when the fruit is fast
To mature, the chlorophyll in the peel is gradually decomposed. Photosynthesis declines, and the inside of the fruit is mainly the transformation of organic matter, rather than the manufacture and accumulation. For example, under the direct irradiation of strong light, it is easy to cause sunburn, so when the fruit is about to mature, it should be covered with leaves.
8. Ripening of watermelon When it needs to be marketed in advance, ethephon (dichloroethyl phosphoric acid) can be used for ripening treatment. The treatment method is that when the size of the fruit has grown and is not yet mature (that is, 25--29 days after flowering), apply 200 mg of ethephon solution per kilogram of watermelon to the surface of the melon before and after the evening. Add a small amount of neutral soap powder to increase the adhesion, and it can be harvested after two days. The processed fruit can be supplied to the market 3-5 days earlier than the naturally mature fruit, and the quality has not been reduced, but has been improved.
9. Pest control The main diseases of watermelon are fusarium wilt, anthracnose, virus disease, powdery mildew and blight.
(1) Disease control Implement crop rotation for more than 4 to 5 years, select disease-free seeds, and soak the seeds with 100-fold formalin solution for 30 minutes for disinfection. The main control methods for fungal diseases: if the diseased plants are found, they should be removed and burned in time, and the diseased holes should be disinfected with lime or 50% dysenium 400 times. In the early stage of the disease, 500 to 1000 times of 50% desenium can be poured in the rhizosphere. Promote watermelon grafting and root replacement technology. Apply decomposed organic fertilizer and increase phosphorus and potassium fertilizer. During the watermelon growth period from May to July, alternately use 70% thiophanate-1000 times solution, 25% carbendazim 500-700 times solution, 50% dysenzinc 1000 times solution, 1:1:200 times solution every 7-10 days. Control methods such as Bordeaux mixture.
(2) Pest control For small cutworms, melon maggots and Huangshou melons, the eggs can be eliminated by ploughing and raking in early spring, and adults can be eliminated with sweet and sour moths. A small amount of water mixed with fresh grass and fried cake fertilizer to trap and kill. Red spider and leafminer can be sprayed with 50% dimethoate 1000 times or 80% dichlorvos 1000-1500 times.
7. Harvest After pollination, early-maturing varieties mature in about 28 days, medium-maturing varieties mature in about 32 days, and late-maturing varieties mature in about 35 days, depending on the temperature. Intuitively, the tendrils near the melon turn yellow, and the umbilical depression of the melon becomes smaller. Note that when picking at high temperature, it can be picked 1-2 days in advance to prevent the melons from being sold in time after picking, and the quality of the melons will be reduced due to excessive maturity.
The maturity identification of watermelon can be identified by various methods such as counting, watching, listening, and measuring.
(1) Calculation It takes more than 80 to 100 days from sowing to harvest for watermelons, 30 days for early-maturing and 35-days for late-maturing.
(2) Look. A few tendrils near the fruit of the ripe fruit wither, the stalk hairs disappear, the pedicle is concave, the stripes on the fruit surface are scattered, the skin is smooth and shiny, and the fruit powder recedes.
(3) Listening to play the melon with your fingers, it will make a dull sound when it is mature, otherwise, the sound is clear and crisp for the raw melon.
(4) Measurement Using the specific gravity method, the specific gravity of ripe melons is 0.9 to 0.95, and those that sink in clear water are raw melons; the large part of the water surface is overripe melons. Only a small portion of melons of moderate maturity surfaced.
(Note: This article is reproduced for reference only)