Key points of tomato management in summer
First, select suitable heat-resistant and antiviral varieties.
Variety selection is the first step of vegetable planting, and it is very important to choose a variety suitable for planting in summer and high temperature season. First of all, this variety has good heat resistance and can set fruit normally at 30-35℃, such as Belle and Baxter. In addition to its heat resistance, it is very important that it is resistant to diseases. In recent years, tomato TY virus disease broke out, especially in summer, and there were many virus-carrying insects, which were easy to occur. Therefore, attention should be paid to the selection of antiviral varieties in virus-infected areas, such as Gleevec.
Second, choose appropriate cultivation methods.
There is a serious misunderstanding in tomato planting in summer, that is, most of them are planted in flat beds. After planting, in order to control weeds, the border was covered with black plastic film, and agricultural operations were carried out on the inner film of the border, which caused the plastic film to cling to the ground, and the agricultural operations and irrigation were discharged together, resulting in serious soil hardening, blocked gas exchange between soil and air, low soil oxygen content and decreased root activity. In view of this situation, the reporter suggested that vegetable farmers change flat border planting into ridging planting. For those who have cultivated the flat border, the center of the border can be turned into a ridge back in combination with soil cultivation, which is generally completed in 2-3 times to prevent excessive soil cultivation from affecting the growth of roots and reducing the absorption capacity. At the same time, pay attention to the way of plastic film covering, and support plastic film with iron wire. , increase the air flow on the soil surface and separate the operation line from the irrigation line.
Third, reasonable close planting.
In summer, tomato planting density in underground arch shed is generally small. Generally speaking, many kinds of watermelons are on the ground. When planting tomatoes in summer, it is also convenient to plant them along the watermelon ditch. As a result, the row spacing of tomatoes is too large. Tomatoes are planted in only two rows, one row is about 2.8 meters, and the average row spacing is about 1.4 meters. Even if the planting density is high, only 1200- 1500 plants can be planted per mu. This not only wastes the land, but also greatly affects the yield, and it is easy to cause sunburn and other problems in the later stage due to excessive sunlight. Therefore, it is suggested that vegetable farmers should thoroughly level the land before planting summer tomatoes, rationally plan the space in the shed, and ensure that the planting is carried out according to a reasonable spacing. Generally, the plant spacing is about 35-40 cm when pruning alone, 45-50 cm when pruning with two poles, and the row spacing is about 70-80 cm, so as to improve the land use efficiency and increase the yield.
Fourth, pay attention to the prevention and treatment of viral diseases at seedling stage.
Tomato virus disease is very serious in recent two years, especially in summer. Many vegetable farmers choose antiviral varieties, thinking that they can prevent and control the virus once and for all. In fact, this idea is wrong. The existing disease-resistant varieties and non-disease-resistant varieties are only different in disease resistance, but not completely immune. In the case of virus infection, antiviral varieties will also get sick, but the disease is relatively mild, sometimes it can't be seen, and it is not unaffected. In addition, the antiviral varieties appearing in the market are only resistant to one or several viruses, and they cannot be guaranteed to have strong resistance to all viruses. Moreover, there are many kinds of viruses that infect tomatoes, so even if antiviral varieties are planted, attention should be paid to the prevention and treatment of virus diseases.
When the seedlings are weak, the disease resistance of the plants is the weakest, especially when the greenhouse temperature exceeds 35℃, the antiviral ability of anti-TY gene will be passivated to varying degrees, which is easy to cause symptoms of viral diseases. Therefore, from the beginning of sowing, it is necessary to do a good job in the prevention of viral diseases, with emphasis on the prevention of seedling stage.
To prevent viral diseases, we must first start with insect prevention and cut off the transmission route of viral diseases. For example, Bemisia tabaci is the main virus-transmitting insect of TY virus, and aphids can spread potato mosaic virus, tobacco mosaic virus and other viruses, so it is necessary to prevent and control Bemisia tabaci, aphids and other virus-transmitting pests in the shed. An insect net is set at the air outlet to reduce poisonous insects from entering the shed. Yellow boards are hung in the shed to trap and kill, and imidacloprid and acetamiprid are sprayed regularly to control pests. After tomato planting, chitin, matrine and mushroom protein should be sprayed every 7- 10 days to improve the antiviral ability of plants and reduce the occurrence of virus diseases.
Five, timely late fruit, first cultivate strong trees.
Many people think that the temperature is high in summer, so we can leave more fruits. However, too many fruits are left in the lower part of the plant, and too many nutrients are consumed, which will seriously affect the growth of stems, leaves and roots, resulting in insufficient supply of nutrients absorbed from the soil and less accumulation of photosynthetic products, which will greatly affect the flowering and fruit setting of red tomatoes in the later stage.
In terms of fruit retention, it is suggested that there should not be too many fruit retention under the plant. If the stems of plants are weak, it is suggested to remove the first ear, cultivate strong trees first, and then leave more fruits. There are three reasons for picking the first ear fruit: first, it is easy to lose the first ear fruit, which is not conducive to high yield of tomatoes; Second, because of the high temperature at seedling stage, the flower buds of the ear fruit are often poorly differentiated, and most of the fruits are deformed and poorly commercialized; Third, the anthers in the experimental site are concentrated, which is convenient for later flowering and removal after the experiment. If the plant grows healthily, 2-3 fruits can be left in the first ear, 3-4 fruits in the second ear, 4 fruits in the third ear and 4-5 fruits in the upper ear. Generally, the first flower per ear blooms 1-2 days earlier than other flowers. After this flower is lit, it is easy to concentrate nutrition on the fruit, which is easy to cause the situation of different sizes of the fruit and affect the commodity rate of the fruit. Therefore, the first flower per ear should not be lit.
Sixth, pay attention to the pruning method.
In addition to the adjustment of greenhouse environment, pruning and threshing methods are also important factors affecting the normal growth and development of plants. Vegetable farmers who are used to planting overwintering tomatoes should pay attention to the management according to the growth characteristics of tomatoes in high temperature season.
In order to cool down in high temperature season, sunshade net is essential, but it is easy to cause plants to grow white and the stems are often thin and weak after using sunshade net. By constantly changing the head, the growth of plants can be adjusted, which is more suitable for tomato cultivation in summer. The method of shaping is to leave two leaves above the second ear after the first and second inflorescences bloom one after another. The lateral branches growing from the nodes directly below the second inflorescence should be retained, and continue to develop upward into the middle trunk, and then continue to core by this method to form a curved upward plant shape. This plastic method is very effective in controlling the vigorous growth in high temperature season, mainly removing the top advantage, promoting the growth of lateral buds, ensuring dense branches and leaves, stout stems and avoiding the injury of strong light in summer.
In winter, due to insufficient light, it is suggested that vegetable farmers remove leaves in time to improve the light transmission conditions of plants and promote fruit ripening. However, this method of picking leaves is not desirable in summer. In summer, long light time and high light intensity have serious effects on the fruits, especially on the top and outside of tomato plants. After the fruit is directly irradiated by strong light, the skin temperature rises and it is easy to get sunburned. Therefore, the reporter suggested not to thresh leaves as early as possible in summer, unless the branches and leaves are too dense, which seriously affects the ventilation and light transmission in the lower part. When the top is located on the last ear, at least two leaves should be left before heading to ensure the shade of the top fruit.
Seven, try to reduce the temperature in the shed.
The main test of tomatoes in summer is the high temperature in summer. When the temperature reaches above 35℃, the assimilated yield and respiratory consumption of plants are in a balanced state, with long jointing, large leaves and thin stems. Moreover, tomatoes are very sensitive to temperature during flowering and fruit setting, and the requirements before and after flowering are more stringent. When the daily temperature rises to 30-35℃, the fruit grows fast, but the color is poor. Therefore, the temperature in the shed should be reduced as much as possible in summer. Ventilation is the basic measure to adjust the temperature, but the outdoor temperature is also very high in summer, even close to 40℃, not to mention the indoor temperature, which must be above 40℃. At this time, on the basis of strengthening ventilation, measures such as shading and spraying water should be taken to reduce the temperature in the shed. Measures such as sunshade net cooling have been introduced in detail in previous articles, so I won't introduce them here.
Some have installed sprinkler irrigation systems in the shed, and there is a sprinkler at the center of the shed skeleton about every 5 meters. The baffle on the sprinkler not only swings under the impact of water, so that water can be sprayed to every position in the shed, which is very effective for cooling down in the shed. However, it is found that when installing this sprinkler system in a greenhouse with a long length, it is necessary to increase the number of pumps to ensure that each sprinkler valve has sufficient water supply. At the same time, sprinkler irrigation can increase the humidity in the shed and reduce the occurrence of virus diseases. If the cost of installing this professional sprinkler irrigation facility is high, micro-irrigation facilities for watering in winter can also be installed, but if the holes are upward, the water can also play a better role in cooling down.