Plastic film mulching is a common technology for vegetable production in solar greenhouse. The use of plastic film mulching can not only improve the ground temperature, reduce the evaporation of soil moisture, and prevent the formation of the ground surface, but also reduce the air humidity in the shed, reduce the occurrence and spread of diseases, and is conducive to the growth and development of vegetables.
However, if the plastic film is used improperly, it is easy to play the opposite role and affect the growth of vegetables. Today, I will talk about the common misconceptions of plastic film coverage.
1. The plastic film is close to the stem base, and the dead tree is serious
Improper plastic film coverage is an important reason for the occurrence of epidemics. Here, we remind vegetable farmers to pay attention to the fact that they should not be close to the vegetable stalks during plastic film coverage.
It is recommended not to cut the film with a blade as much as possible, but to dig the film with a finger to ensure that the hole is large and will not be closed. Generally, the diameter is 5-8 cm. At the high temperature stage, roll up both sides of the plastic film to prevent the ground temperature from being too high; When the temperature drops, pull off the plastic film, and clamp the two adjacent plastic films with a grafting clamp so that the plastic film does not touch the stem.
2. The whole shed is covered with plastic film, which affects the root growth
When many vegetable farmers cover the plastic film, they directly cover the whole shed with the plastic film. After countless times of treading, the operating plastic film is closely attached to the ground. When the planting line is watered, the plastic film will also be pressed, which seriously affects the permeability of the soil, hinders the respiration of the vegetable roots, and causes poor root development.
In fact, it is better to use steel wire or bamboo pole to support the plastic film in the planting line, and cover the plastic film on the support pole every 50cm from south to north. This can realize watering under the film, which not only improves the permeability of the soil, but also makes it difficult for moisture to volatilize outside and reduces the humidity in the shed.
3. Film mulching of vegetables in autumn is too early, which is not conducive to deep rooting
In greenhouse vegetable cultivation, the time of covering plastic film should be determined according to the specific climate conditions. For example, after the Autumn Cucumber is planted, the outside temperature is high. If the cucumber is covered with plastic film immediately, on the one hand, the temperature of plastic film is too high, and the root is likely to be blocked; On the other hand, after mulching with plastic film, a humid environment will be formed on the surface layer, which is not conducive to the root system to grow, which may lead to the failure of crouching seedlings, and it is difficult to cultivate strong seedlings and trees. Therefore, it is suggested that the plastic film should be covered after 15 days of planting according to the specific weather conditions, which is conducive to the root system of seedlings to grow and grow strong trees.
4. Covering the plastic film only in the operation line is completely wrong
Some vegetable farmers only covered the operation row in the shed, but the planting row was not covered with plastic film. This practice not only does not give play to the advantages of plastic film coverage, but also highlights the disadvantages and has a poor effect.
In greenhouse vegetable production, the most important role of plastic film mulching is to reduce the humidity in the greenhouse and reduce the occurrence of diseases. The practice of covering the operation line with plastic film and not covering the planting line is not conducive to reducing the humidity in the shed, because most of the time when vegetables are watered, the planting line is watered, and the planting line is not covered with plastic film can not play a great role in reducing the air humidity, nor can it play the role of heat preservation. The disadvantages of mulching plastic film on the operation line are also obvious, which greatly reduces the permeability of the soil in the operation line and affects the growth and development of the root system.
5. The film is not tightly sealed, causing vegetable burns
In sunny and high-temperature weather, the film is not tightly sealed, and it is easy to burn vegetables. This is mainly due to the light transmission and temperature increase of the plastic film, which vaporizes the water of the ground soil layer and forms water droplets on the surface under the film. When the planting holes are exposed, the vaporized hot air under the film will rush out from the holes. The temperature of this vaporized hot air, especially when the temperature is high at noon on a sunny day, will often burn the seedlings or cause heat damage to the leaves, roots or stems of vegetables, which can not only cause plant damage, It is also easy to infect pathogenic bacteria and cause diseases such as stem base rot, which may cause lack of seedlings or affect the normal growth of plants. In serious cases, it may lead to production reduction.
In addition, when it is sunny and high-temperature, the leaves of the plant contact with the plastic film. At this time, the plastic film temperature is high, and it is easy to burn the leaves. This problem occurs more when the black plastic film is covered.
Preventive measures: after the plastic film covering of vegetables is completed, fine soil can be pressed on the plastic film to seal the planting holes to prevent the hot gas in the plastic film from burning the vegetables. At the same time, pay attention to the weather in time. In case of high temperature and strong light, cover the shading net in time to prevent the temperature in the shed from being too high.
If the plant is found to be burned, the fine soil shall be pressed on the plastic film around the plant at the first time, and the gap between the plastic film and the plant shall be sealed to prevent the high temperature in the plastic film from continuing to harm.
In addition, according to the degree of burn, the medicine containing brassinolide, gibberellin and other components can be sprayed to regulate the growth of plants, strengthen the management of fertilizer and water, strengthen the root system of plants, and make the plants recover quickly.
If the row covered seedlings are small, in order to prevent the occurrence of stem base rot and other diseases after heat damage, some protective fungicides can be used to spray for prevention. If the plant damage is serious, remove it in time and plant new plants to reduce the loss.