The fruiting period of over-summer tomatoes is at the highest temperature in a year. The temperature in the shed often exceeds 40 ℃, and it is prone to flowering and fruit setting and serious physiological diseases. So, what points should be grasped in planting management?
1. Choose the right heat-resistant and anti-virus varieties
Variety selection is the first step in vegetable cultivation. It is very important to choose a variety suitable for high-temperature summer season. First of all, this variety has better heat resistance. It can sit normally at a temperature of 30-35°C. In addition to its heat-resistant properties, an important point is its disease resistance. In recent years, outbreaks of tomato TY virus disease, especially over-summer tomatoes, have a lot of poisonous insects and are prone to occur. Therefore, we must pay attention to selecting anti-virus varieties in the virus disease epidemic area.
2. Choose the right cultivation method
There is a serious misunderstanding in the cultivation of over-summer tomatoes, that is, most of them are planted with flat borders. After planting, in order to control weeds, the borders are covered with black mulch. The agricultural operations are carried out on the mulch inside the borders, which causes the mulch to be tight. Sticking to the ground, agricultural operations and irrigation are in the same row, resulting in severe soil compaction in the row, the gas exchange between the soil and the air is hindered, the oxygen content in the soil is low, the root vitality is reduced, affecting the absorption of water and inorganic nutrients by the root system, the plant growth is weak, the expansion If the speed is slow.
In view of this situation, it is recommended that vegetable growers change flat border cultivation to ridge planting. For flat border cultivation, the center of the border can be changed into ridge back in combination with soil cultivation, which is usually completed in 2-3 times of soil cultivation to prevent excessive soil cultivation at one time. It affects root growth and reduces absorption capacity. At the same time, pay attention to the mulching method, use iron wire to support the mulching film, increase the air flow on the soil surface, and separate the operation row from the irrigation row.
3. Reasonable dense planting
The planting density of over-summer tomatoes in arch sheds is usually small. In some places, the stubble is mostly planted with watermelon. When planting over-summer tomatoes, it is also planted along the watermelon ditch for the convenience of operation. As a result, the row spacing of the tomato is too large. Only two rows of tomatoes are planted in a row of about 2.8 meters, with an average row spacing of 1.4. Meters. Even if the planting density is large, only 1200-1500 plants can be planted per mu. In this way, not only the land is wasted, the yield is greatly affected, but also the late light is too strong, the fruit is prone to sunburn and other problems.
Therefore, it is recommended that vegetable farmers level the land comprehensively before planting over-summer tomatoes, plan the space in the shed reasonably, and ensure planting according to a reasonable plant row spacing. Generally, the plant spacing is about 35-40 cm for single stem pruning and 45-50 cm for double stem pruning. The row spacing should be kept at around 70-80 cm to improve land use efficiency and increase production.
Fourth, pay attention to the prevention and treatment of virus diseases at the seedling stage
Tomato virus disease has been very serious in the past two years, especially over-summer tomatoes, many vegetable farmers have chosen anti-virus varieties, thinking that this will be once and for all, and no longer need to control the virus. In fact, this idea is wrong. Existing disease-resistant varieties and non-resistant varieties only differ in their resistance, and are not completely immune. When encountering virus infection, anti-virus species will also develop, but the incidence is relatively mild, sometimes it is not visible, and it is not unaffected.
In addition, the anti-virus varieties that are currently on the market are only resistant to one or a few viruses, and cannot guarantee that they will be resistant to all viruses. There are many types of viruses that infect tomatoes, so even if they are planted with anti-virus Varieties, we must still pay attention to the prevention and treatment of viral diseases.
Plants at the seedling stage are weak and weak, which is the time when the plants have the weakest disease resistance, especially when the temperature of the greenhouse exceeds 35 ℃, the anti-TY gene anti-viral ability will be inactivated to varying degrees, and it is easy to cause symptoms of viral disease. Therefore, from the beginning of planting, we should do a good job in the prevention of viral diseases, and focus on prevention at the seedling stage.
To prevent viral diseases, we must start with insect control and cut off the transmission of viral diseases. For example, Bemisia tabaci is the main virus-infecting insect of TY virus. Aphids can transmit a variety of viruses such as potato mosaic virus and tobacco mosaic virus. In the shed, the prevention and control of the beetle-borne pests such as Bemisia tabaci and aphids should be done well. Insect nets are installed at the vents to reduce the transmission of poisonous insects into the shed. Yellow boards are hung in the shed to lure them. At the same time, imidacloprid and acetamiprid are sprayed regularly to prevent and control pests. After the tomatoes are planted, chitin, matrine, mushroom protein, etc. should be sprayed every 7-10 days to improve the plant's ability to resist viruses and reduce the occurrence of viral diseases.
5. Retain fruits at the right time and cultivate strong trees first
Many believe that the summer temperature is high, and more fruit can be left. However, excessive fruit retention at the bottom of the plant and excessive nutrient consumption will seriously affect the growth of the stems, leaves and roots, resulting in insufficient nutrient supply from the soil, little accumulation of photosynthetic products, and a fall. Will be greatly affected.
In terms of fruit retention, it is recommended not to leave too much fruit under the plant. If the stalks of the plant are weak, it is recommended to remove the first spike and cultivate the strong tree first, and then leave more fruit. There are three reasons for removing the first ear fruit: one is to retain the first ear fruit and it is easy to fall into the tree, which is not conducive to the high yield of tomato; the second is because the temperature at the seedling stage is high, the flower fruit bud is often poorly differentiated, and the fruit produced is also Most of them are deformed and have poor commerciality. The third is the concentration of anthers at the test point to facilitate the later flowering. After the test is completed, they are removed.
If the growth of the plant is relatively strong, the first ear can retain 2-3, the second ear can retain 3-4, the third ear can retain 4 and the upward ear can retain 4-5. The first flower of each panicle generally opens 1-2 days earlier than the other flowers. After holding the flower, it is easy to cause nutrient concentration to supply the fruit, and it is easy to cause the size of the fruit to vary, which affects the commodity rate of the fruit. The first flower of the spike flower should not be spotted.
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