The early maturing cultivation of southern watermelon has been paid more attention to by people. The protection facilities adopted have been improved. The natural resources such as warm light and light have been fully utilized. Through careful cultivation and management, the maturity period has been from the middle of July to the middle of June, and early to late June. Furthermore, the economic benefits have been significantly improved as early as the end of May and the beginning of June. Because the growth period is advanced, it can be placed before the mildew rain, thus enhancing the ability to resist natural disasters. This is an important measure for early maturity, high yield and stable production in the rainy areas of the middle and lower reaches of the Yangtze River. At the same time, early maturing cultivation and planting late rice in advance will have a certain positive effect on ensuring grain production. The area of ​​early-maturing cultivation in Jinshan and Nanhui in the suburbs of Shanghai and Pinghu and Jiashan in Zhejiang has been expanding year by year. According to statistics from Jinshan County, the area of ​​early maturing of watermelon accounts for about 65% of the total area cultivated by watermelon.
Jinshan County is one of the bases for early maturity cultivation of watermelon in the suburbs of Shanghai and even in the middle and lower reaches of the Yangtze River. It has rich experience in early-maturing cultivation, mainly using small arch sheds for cultivation, and early seeding and nursery season, the nursery facilities have been greatly improved, after planting Adopting simple insulation method, the technical measures are more complete, the effect is very significant, and the success is more grasped. For example, in 1991, under the condition that the prevailing rainy weather was very bad, it still achieved a good yield of 1500-2000 kg per mu and an income of more than 1,500 yuan per mu. Results. In recent years, on the basis of the original early maturing cultivation, it has gradually developed into a special early-maturing cultivation and early-maturing cultivation technology. Special early-maturing cultivation is advanced to the middle and late February, sowing in the cold season. In order to keep warm the seedlings, use the large (medium) shed and the soil temperature to raise the seedbed. After the planting, in order to avoid the low temperature attack, in the small arch shed Cover the saving shed. Early-maturing cultivation was carried out in a small shed (cold bed) in mid-March, and planted in a small arch shed in mid-April. As the temperature began to rise, in order to save costs, the film was replaced with a mulch, and the shed was in the form of a simple shed. Fruits are harvested in the middle and late June, and the key to its cultivation techniques are:
1. Variety selection Special early maturity cultivation should select varieties with low fruit set, short fruit development period, large harvesting maturity, low temperature resistance and low light tolerance, such as the development and production of Qingnong Watermelon Research Institute of Daqing City, Heilongjiang Province. Qingnong No. 3, black age children, 84-24 and other early maturing varieties. Early maturing cultivation should also use the above early maturing varieties, but in some areas and farmers, the varieties of medium maturity are often used for early maturing cultivation, such as Qingnong No.5, Qingfa No.8, Extraordinary Qinghongbao, Jubao III. No. and other varieties. Although the above varieties are cooked for several days, the early yields increase rapidly, and the total yield is higher than that of the early maturing varieties. Taking measures from cultivation techniques can shorten the gap with the harvesting and supply period of early maturing varieties.
2. Seeding and seedling cultivation for early maturity, seedlings must be planted in advance, transplanted with large seedlings, and planted in advance. The sowing period can be early to mid-to-late February. At that time, the weather was cloudy and the temperature was low. If the general cold bed seedlings were used, the heat source was insufficient, the heat preservation performance was poor, and the requirements for temperature conditions of the seedlings could not be guaranteed, so the success rate of seedling cultivation was low. Therefore, according to local conditions, a large shed canopy seedbed is used. Through two layers of coverage, the insulation capacity is improved and the lighting conditions are improved. The seedling shed has a span of 4 meters and a small arch shed with a height of 1.6 meters. It is covered with two layers of plastic film. The bottom of the bed is dug with a bed hole of about 30 cm. It is padded with pig, cow, sheep, fresh manure and garbage. The heating line is heated, and the power of the heating line is 120 watts/square meter. The average daily temperature and the minimum temperature of the greenhouse shed are 3-5 °C higher than that of the small shed. Due to the large volume, the temperature is relatively stable, especially to prevent the effects of low temperature and freezing damage at night, and can also be overlaid on the small arch shed during the cold period. The straw curtain is kept warm, the ground temperature is raised, and the temperature condition of the watermelon seedling is ensured. According to the Jinshan County Agricultural Research Institute, the ground temperature reached 16.3 °C on February 11, and the ground temperature of 5 cm was 22.4 °C when the shed temperature reached 13.7 °C in late February, so that watermelon could be safely planted and emerged.
Early maturing cultivation is carried out in early March, and the temperature is already relatively high. Therefore, it is sufficient to use a small-arched cold bed to raise seedlings. However, for safety reasons, hot stuff can be placed at the bottom to increase soil temperature and accelerate the growth of melons. .
The climatic conditions during early maturing cultivation are relatively poor, the double-film coverage is poor, the air humidity is high, and the seedlings are prone to disease and disease. Therefore, the management during the nursery period should be strengthened. First, strict temperature control should be carried out according to the needs of different periods. The seedling temperature should be raised during seeding and seeding, and the seeds should be germinated and unearthed. The soil temperature should be controlled at 25-30 °C. When the seedlings are released to the first true leaf stage, the temperature should be appropriately lowered to prevent the elongation of the hypocotyls. Generally, the temperature is maintained at 20-25 °C during the daytime. After the first true leaves appear at night at 15-20 °C, the temperature should be increased to promote the seedlings. Growth, usually about 25 ° C during the day and not less than 15 ° C during the night. 5 to 7 days before planting, cooling exercises should be carried out to improve the adaptability of seedlings, which can be maintained at around 20 °C during the day and 13-14 °C during the night. In addition, attention should be paid to cold protection. In addition to sealing the shed at night, straw curtains or other coverings can be added to the shed to prevent frost, and to be exposed during the day to receive light. When the shed temperature is high during the day, the small arch shed should be ventilated in time to reduce air humidity and improve lighting conditions. Before the melon seedlings are unearthed, sufficient water conditions are needed. After the true leaves of the seedlings, the humidity of the seedbed should be controlled to promote the growth of the roots. For example, the cracking of the bed surface can cover the moisturizing of the wet soil, and at the same time, the air humidity of the seedbed should be prevented from being too high. When the bed temperature is too high, the ventilation should be increased: when the air humidity is too low, it can be sprayed with warm water in the seedbed to increase the air humidity. In short, it should be prevented that the seedbed is caused by high temperature and high humidity, or the occurrence of squatting due to low temperature and high humidity, and the water loss and wilting caused by high temperature and low humidity. If the long-term rainy weather during the nursery period is formed, the melon seedlings are very weak. At this time, the weather suddenly turns to a strong light, which is very likely to cause water loss and wilting. Therefore, it is not appropriate to immediately remove the film to reduce the air humidity. First adopt short-term shading, continue to maintain the high humidity in the shed, first accept the scattered light, gradually adapt to the air and then expose the film to receive strong light.
The seedbed management of early-maturing small arch shed seedlings is basically the same as above, but the temperature and humidity control is more difficult. If there is continuous low temperature in early spring, the seedlings still have certain risks.
3. The planted melon land should be prepared in the first year of winter planting, the width of the raft is 4 - 4.5 meters, the east-west direction, the width of 1.2-1.5 meters of the early-maturing barley on both sides, the middle 1.5 - 2 meters for the reserve melon In the winter, the drainage ditch is opened, and the melons are to be ploughed 2 to 3 times to loosen the soil. In the early spring, apply 1,500-2,000 kilograms of high-quality pigs, 15 kilograms of superphosphate, 15 kilograms of potassium sulfate or 75 kilograms of ash, and mix well with the soil. Then, the surface of the sputum will be poured 1500-2000 kilograms per mu. One week before transplantation, when the field moisture is suitable, the pineapple ridges are topsoiled, flattened, and immediately covered with mulch to absorb heat and increase ground temperature.
The transplanting period of special early maturing cultivation was in early March, when the temperature and ground temperature were relatively low. It should be planted on a sunny day to facilitate the growth of roots. After planting, set up a simple shed and make a shed with a bamboo piece about 1 meter long. Covers the mulch with a width of about 1 meter. The simple shed is 70-80 cm wide and about 30 cm high. It is then placed in a small arch shed in the ridge of the melon. The width is 1.2-1.4 m, the height is about 60-70 cm, and the agricultural film with a width of 2 m is covered. The frame is fixed with a rope net to prevent wind.
Early maturing cultivation was planted in early April. At that time, the temperature and ground temperature were relatively high. Generally, only one layer of plastic film was covered. The specifications of the small arch shed were the same as above. Due to the short covering time of the early maturing cultivation, the width of the small shed can be reduced to about 1 meter for the cost saving, and the mulch film with a thickness of 0.05-0.3 mm is used, and the membrane volume per mu is only 4 kg, which greatly saves the economy. cost.
The special early-maturing cultivation was planted in the center of the melon ridge, and the plant spacing was about 75 cm, and 650 plants per acre were planted. Early-maturing cultivation is carried out by double-row triangle planting, and the melon seedlings are planted at a distance of 15 cm from the center to take advantage of the optimal position of the temperature and illumination conditions of the greenhouse. The plant spacing can vary from species to species, Qingnong No.3, Black Age Children, 84- The distance between the 24 early-maturing varieties is 35-45 cm, and about 650 plants per acre are planted. The early and middle-aged Qingnong No.5, Qingfa No.8, and Extra-large Qinghongbao are about 55 centimeters long and planted 600 acres.
4. After temperature management, the main purpose is to use sunlight energy and heat preservation measures to increase the accelerated growth of greenhouse temperature, especially for early ripening. The temperature is still low when planting in mid-March. Therefore, increasing the temperature of the greenhouse is the key to successful cultivation. 7 to 10 days after transplantation, the film on the small arch shed and the simple shed should be tightly covered to increase the temperature of the shed to promote root growth and accelerate growth. When the temperature of the shed reaches 30 °C or above, it can be properly ventilated. At noon on the sunny day of April, proper ventilation should be carried out to reduce the humidity of the air, increase the transmittance of light, and improve the quality of the seedlings. However, it is mainly covered and insulated on cloudy and nighttime. Later, as the temperature rises, the ventilation surface and ventilation time are gradually increased. The temperature is stable above 15 °C around mid-April. The melons are elongated and female flowers appear. The mulch on the shed can be removed. In the first half of May, the temperature reached 17.5 °C, which basically meets the requirements of temperature conditions for watermelon growth. On sunny days, the film on both sides of the small shed can be rolled up to the top, and at night, depending on the growth of the melon seedlings, if the plants grow vigorously, at night It is not necessary to cover the film to properly cool it to make it grow normally. If the plant is slow to grow, the film should be continued at night to promote growth. The film should be lowered to prevent rain during rainy days. After mid-May, when the plants have all taken fruit, the scaffolding and film of the small arch shed should be completely removed.
In addition to normal temperature management, local weather forecasts should be kept in mind to prevent freezing damage caused by low night temperatures. If necessary, cover the hay on the shed to improve the insulation capacity. At the same time, check the windproof net to avoid the windy diaphragm. In warm sunny days, sometimes the shed temperature is as high as 40 °C or more, and it is easy to burn the plants. At the same time of ventilation and cooling, the humidity conditions in the shed vary greatly. Generally, the humidity is higher under the condition of lower temperature and tighter, and the humidity is drastically reduced when the ventilation is increased after heating, which is easy to damage the seedlings. It has been observed that at a temperature of 40 ° C and a closed condition, when the air humidity is above 60%, the plant can still maintain normal growth. Therefore, when the continuous rainy weather is clear, the film should be ventilated before 9:00 am. It is forbidden to ventilate before and after noon. At this time, the water in the ventilator is largely lost, and the humidity drops rapidly, causing the seedlings to lose water and damage the seedlings.
The temperature management in the early stage of early maturity cultivation should be based on heat preservation, but the maximum temperature should not exceed 35 °C. Because the early maturing cultivation is a single layer covering, the small shed has poor heat preservation capacity. Therefore, the straw shed can be covered with straw curtain insulation in the early stage. Ventilation management should be flexible according to the weather and the condition of the seedlings. When the night temperature stabilizes through 20 ° C, it can be ventilated day and night. In the end of May, the scaffolding and film were removed, and the work of the vines was done.
5. Fertilizer management Special early maturity cultivation When the shed is removed in mid-April, 1 heavy fertilizer is applied, 1500-2000 kg per mu of livestock and poultry, 15 kg of phosphorus and potassium fertilizer, on both sides of the ridge, about 1 from the root Divide into the rice. From early April to early May, the weather is often fine, the rainy days and rainfall are relatively small, the growth of watermelon is very good, the plants grow rapidly, and enter the stage of bud and flowering and fruiting. At this time, attention should be paid to maintaining soil moisture, appropriate Watering. When the first batch of melon eggs is large, the fertilizer is applied, generally 1500-2000 kg of clear water dung or pig urine, 0.4 kg per 100 kg of urea, about 1 m from the root, the concentration is flexible according to soil moisture. , the expansion of melon fertilizer should master the principle of first knot first, more knots and more.
The early-ripening cultivated rattan fertilizer, the application method and the amount of fertilizer applied are the same as above. However, due to the late growth period, it can generally be postponed for 10-15 days. The expanded melon fertilizer after fruit setting is also the same. However, the plants grow well, and they can also fight for the second time to increase the yield. Generally, after most of the first batch of melons are harvested, 1,500 kilograms of manure per acre are applied, and 0.3 kilograms per 100 kilograms of urea is added, 3 to 4 days. Times. After molding, we should master the principle of more water and less fertilizer, and strive to rejuvenate the seedlings. At the same time, we must do a good job in weeding, melon-covered grass or covering soil to protect roots and pests.
6. Promote the flowering fruit setting period of early ripening of fruit set in late April to early May, the temperature during fruit development is low, and the fruit shape of the early low knots is smaller, the proportion of deformed melon is higher, ideal fruit setting. The node is the second female flower on the vine, and at the time it is still under the condition of mulching, the insect activity is very small. Therefore, artificial ribs should be carried out at 7-9:00 every morning during the opening period of the second female flower of the main vine. Early fruit set, requires 1000 fruit per acre, 800 results, a single melon weight 4 - 5 kg, in order to achieve an indicator of 3200 - 4000 kg per mu.
In the mid-May period when the temperature of early maturing is high, in order to get the initiative, we should pay attention to artificially assisted pollination in order to get fruit in time.
7. In addition to paying attention to rotation, pest control, and strengthening management to improve the disease resistance of plants themselves, it is necessary to strengthen the prevention and control of pests and diseases. The anthracnose bacteria are alternately used with 1000 times of methyl thiophanate or 500 times of zinc and 1â„2:200 times of Bordeaux mixture. The principle of light seedling period and heavy weight after the expansion of the melon period should be mastered. medicine. The leaf miner is sprayed with 2000 times of dimethoate. The red spider uses 3000 times gram, sprays once every 7 days, or 2000 times, and sprays once every 3 days.
8. Several issues that should be noted
First, the early-maturing cultivation of southern watermelons, especially the early-maturing cultivation, is carried out in a season with relatively bad climatic conditions. The investment cost is relatively high, the technology is very strong, and there are certain risks. All localities should be based on local natural climatic conditions, economy and technology. Level, gradually developed on the basis of successful trials in small areas.
Second, the supply season of watermelon early maturing and special early maturing cultivation is in June. If the proportion of early maturing cultivation area is too high, the peak period of watermelon supply will be early. Because the temperature is still low, the market consumption is not large, and may be It brings difficulties to sales. Even if it is early maturity, it is difficult to form an advantage, so that it cannot obtain high economic benefits, so it cannot blindly pursue precocity. All localities should be reasonably matched in the early, middle and late stages, and a certain area of ​​early maturing and early maturing cultivation should be arranged to extend the supply period of watermelon.
Third, the key to early maturing cultivation is to plant seeds in advance, cultivate robust seedlings, plant in advance under heat preservation conditions, and flower and fruit early. Because of the early production season, it is necessary to improve the seedling insulation facilities and improve the insulation performance of the small arch shed. The large (medium) shed sheds promoted by Jinshan County Agricultural Science and Technology Co., Ltd. are feasible by using bio-heating (or electric heating line) to warm the seedlings. The use of small sheds and simple sheds to plant melon seedlings improves the thermal insulation at night. It also saves costs, overcomes the problem of frost damage during the cold wave, and plays a great role in stabilizing the early ripening of watermelon.
Fourth, early maturity, pre-supply refers to the premise that the fruit is mature and has excellent quality of food products, but in fact there is a premature method of preemptively picking up raw melon or adopting unreasonably reducing quality, which harms the interests of consumers. This kind of behavior should be stopped.
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