Greenhouse vegetables beware of "eight evils"

Fertilizer: Fertilizer is caused by improper application of fertilizer to vegetable seedlings. The initial performance of the fertilizer begins from the lower leaves, wilting at noon, and can be restored in the morning and evening. It is difficult to recover in the morning and evening when it is severe. The reason for this is that when the nutrient soil is formulated, excessive fertilizer or unripe livestock manure is mixed, causing excessive pressure on soil moisture. The roots are difficult to absorb water and "burn seedlings". Prevention should be based on prevention. In the preparation of nutrient soil, it is necessary to use mashed and fully decomposed organic fertilizer, and strictly according to the technical requirements, the top dressing must be combined with watering. In the event of fat damage, water should be poured immediately to reduce or relieve symptoms.

Phytotoxicity: Due to the small space and good airtightness of vegetable production in solar greenhouses, improper use of pesticides may cause phytotoxicity. Some bactericides such as mancozeb, chlorothalonil, and anti-virus cockroaches can cause phytotoxicity when the concentration is too large. In addition, some vegetables are very sensitive to some insecticides, and even a small amount of use can cause serious phytotoxicity. Once a phytotoxicity occurs, spraying a nutrient such as “Plant Power 2003” can alleviate the phytotoxicity.

Ammonia: Ammonia is a hazard to vegetables when the concentration of ammonia in the air in the greenhouse reaches a certain level. When the ammonia poisoning occurs in vegetables, it often shows that the leaves are rapidly wilting, and then the wilting is dry and burning. The first method of prevention and control is to select the combination of watering and topdressing in continuous sunny days, and the cake fertilizer and other organic fertilizers should be turned into the soil in time. The second is to timely ventilate after topdressing to prevent ammonia accumulation. The pH of the test chamber can be used to detect the ammonia content in the greenhouse. Use the pH test paper to pick up the water drops on the shed film. When the pH value is >7, the ammonia gas is present, and the air should be released in time. When the pH is ≤ 7, it means that there is no ammonia in the greenhouse.

Cold damage and heat damage: The solar greenhouse production does not pay attention to heat preservation and humidification, which is easy to cause cold damage. The temperature is too high and it is easy to cause heat damage. Generally, as long as the conventional insulation measures are implemented, the temperature of the greenhouse is not lower than 0 °C, and the vegetable seedlings will not be directly frozen. However, some warm vegetables such as cucumber and eggplant will appear when the night temperature is lower than 8 °C for 5 consecutive days. Cold roots, which in turn lead to dead roots. Most of the heat damage is caused by human factors. For example, if you don't pay attention to the wind at noon on sunny days, the temperature in the greenhouse will be above 40 °C, and the seedlings will lose water and dry up. As long as you look at the thermometer, if you exceed the required temperature and release the wind in time, there will be no heat damage.

Diseases: The temperature in the solar greenhouse is high and the humidity is high, which is beneficial to various diseases. In practice, the use of agricultural control and chemical control measures in combination with disease prevention and control, and the adoption of agricultural measures such as planting disease-resistant varieties, adding organic fertilizer, mulling cultivation, releasing air, demulsing mulch and submerged darkening will all reduce the occurrence of diseases.

Flash seedlings: The weather is suddenly cloudy for a few days, and it is eager to pull the grass to dry the seedlings, often causing the plant to suddenly wilting, or even the whole plant to die, the mass is commonly known as "flash seedlings." To prevent "flashing seedlings", one should still insist on pulling the straw curtains during cloudy days. It can be pulled late and placed early. The weather can be cold. The grasshoppers can be rolled up about 1 meter at the front end of the greenhouse front slope and the rear slope, so that the seedlings can accept some Scattered light; second, after the weather is fine, all the rolls are drafted before the morning sun comes out to 10 o'clock. Do not let the wind blow. When the sun is strengthened after 10 o'clock, put half of the haystacks. If the seedlings are snoring, spray the water on the vegetable seedlings. Improve the humidity of the air in the greenhouse and prevent the leaves from losing water. This should be observed continuously for 2-3 days, until the seedlings adapt to the sunny day before they can be transferred to normal management.

Gas damage: Gas damage refers to the harm caused by harmful gases to greenhouse vegetables. Most of the harmful gases are caused by human factors, such as the generation of coal or firewood in the greenhouse to produce a large amount of smoke and SO2 gas. Excessive doses when using aerosols and pesticides can also cause damage to vegetable seedlings. To prevent gas damage, first, the greenhouse must be heated to prevent harmful gases from entering the greenhouse. The second is to strictly determine the dosage according to the instructions for use of the medicine when smoking the shed, and do not blindly increase the dose.

Herbicide: Vegetable seedlings are extremely sensitive to a variety of herbicides. Misuse of herbicides, removal of grass film or use of sprayers sprayed with herbicides can cause seedling damage. Vegetables are difficult to remedy after being harmed by herbicides. Even if they can resume growth, they will reduce production and reduce income. Therefore, it is necessary to be vigilant and prevent the misuse of herbicides, lawn membranes and sprayers sprayed with herbicides.

Single brush

Beauty Brush Set,Synthetic Makeup Brush,Soft Makeup Brushes

Liya Beauty Accessories Co., Ltd. , http://www.chinapowderpuff.com