In the case that greenhouse vegetables are not heated, some simple and easy control measures can be taken to ensure the normal growth of greenhouse vegetables to some extent. The following are some common and effective methods.
Prepare hot land. Hot soil is made of chicken manure, hot organic manure, cow dung and other breathable fertilizers, that is, 20% and 60% are mixed with fine soil when they are decomposed. This nutrient soil has good heat absorption and production performance, which makes vegetable seedlings grow in a good environment, with a large number of roots and strong absorption function. The grown vegetables are robust and naturally cold-resistant.
Seedling raising in nutrient bowl. Using black plastic nutrition bowl to raise seedlings, absorb heat and protect roots during the day, when the outside temperature is below zero, the temperature in the shed is about 5℃, while the temperature in the nutrition bowl can reach about 8- 10℃, so the vegetable seedlings grow slowly and will not be frozen.
Controlled application of nitrogen fertilizer. Reduce the amount of nitrogen fertilizer at seedling stage appropriately and avoid unilateral application of chemical nitrogen fertilizer to avoid poor cold resistance of vegetables. Top dressing should be done as soon as possible to make vegetables and seedlings healthy. Quick-acting nitrogen fertilizer should not be applied before low temperature, and phosphorus and potassium fertilizer should be applied at one time to enhance cold resistance. The light is weak in winter,
Vegetables have poor ability to absorb fertilizer. Spraying photosynthetic micro-fertilizer on leaves can prevent element deficiency caused by insufficient absorption of nutrients by roots. At the same time, growth hormone should be used less or not to prevent soft growth and reduce cold resistance. Shallow intertillage for heat preservation. The surface of vegetables is hard, and the hot air is restricted from entering the tillage layer during the day, so the heat storage will be reduced. In addition, the cracks are large and deep, the soil aggregate structure is poor, it is easy to dissipate heat in the first half of the night, and the room temperature is low in the second half of the night, which is easy to cause cold damage. If shallow intertillage is carried out on the greenhouse soil, it can break the hardening and repair the cracks, which can not only control the transpiration of groundwater to take away heat, but also keep moisture and heat, prevent cold and protect seedlings. Rooting element irrigates roots. After using rooting agent, the root system of greenhouse vegetables can be increased by about 60% and the root depth can be increased by about 25% in winter. If the root system is developed and the absorption capacity is strong, vegetable seedlings will not be frostbitten because of poor cold resistance caused by lack of water and elements.
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