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    1. Several major relationships that should be paid attention to in watering in winter sheds

    1. The relationship between watering and ground temperature

    The ground temperature of greenhouse vegetables is usually 3°C-8°C higher than the lower limit of the greenhouse temperature. After watering once, the ground temperature is mostly lowered from 20°C to below 10°C, which is easy to break through the minimum ground temperature required by vegetables. The root system of vegetables causes great damage and affects the growth of vegetables. This requires that watering in winter should be carried out on sunny days. It is necessary to increase the greenhouse temperature by about 2 °C on the first day and the day of watering, and increase the greenhouse temperature by 3 °C on the first day after watering. Raise the ground temperature to make the ground temperature drop smaller and recover as soon as possible. In winter, the watering amount of vegetables should also be appropriately reduced. If the watering amount is large, the ground temperature will recover slowly after watering, which will cause physiological diseases of vegetables.

    2. The relationship between watering and water demand

    When the vegetables are not watered during drought, the branches and leaves of vegetables will wilt or even dry out, and the fruit will have dull skin or umbilical rot due to drought. If it is not watered when it is not dry, unless the vegetables have special physiological needs, it is very easy to cause rot and root rot, which will seriously affect the growth and development of vegetables.

    3. The relationship between watering and air permeability

    Watering and ventilation After vegetables are watered, the water occupies the space in the soil, so that the air in it is discharged, and the root system of vegetables needs to breathe air, and insufficient air supply will suffocate the root system. If it is not good, the roots will turn brown, the capillary roots will die, and even rot will cause diseases and dead trees. Especially in some vegetable fields with sticky soil, the clay soil has poor air permeability originally, and its air permeability will further deteriorate when watered. 

    Second, pay attention to the method of watering

    1. It is recommended to use drip irrigation, avoid flood irrigation

    Changing ordinary furrow watering to drip irrigation under the film can increase the ground temperature by about 5°C and reduce the air humidity by about 10%, thereby reducing the disease by more than 30%.

    2. Arrange the watering time reasonably

    In winter, greenhouse vegetables should be watered around noon, preferably after 10 am and before 3 pm. During this period, the greenhouse temperature is higher and the side effects are minimal after watering. Avoid watering in the morning and evening to prevent freezing of vegetables.

    3. Pay attention to the watering site

    Different parts of the watering have emphasis. The temperature of various parts in the greenhouse is quite different, and the amount of watering should also be different. For example, the temperature in the southern part of the greenhouse and the places near the stove, flue and other heat sources are higher, the soil moisture evaporation is large, and the watering amount should be larger; The temperature on the side and the north is lower, the sunshine time is short, and the amount of watering should be less.

    4. Take good care of management after watering

    Do a good job of shed vegetable management after watering. After watering in winter, it is easy to cause problems such as low temperature, high humidity, and many diseases in the greenhouse. Therefore, in the first two days after watering, the temperature should be raised to about 40 °C at noon, and the greenhouse should be stuffed for 1 hour to increase the inland temperature of the greenhouse.

    Three, watering matters needing attention

    1. Pay attention to the weather, pay attention to moisture content

    Be sure to watch the weather forecast before watering, not only to choose sunny days for watering, but also to ensure that there are 2-3 days of sunny days after watering, so as to avoid rainy weather after watering, which will increase the humidity in the shed and reduce the ground temperature , Diseases are frequent, and more attention should be paid in the deep winter. It is not suitable for watering in the first two days after the cloudy day and the sudden sunny day. The mild ground temperature of the shed should be raised first to make the plants basically return to normal before watering.

    2. Pay attention to the ground temperature and cover with mulch

    The daily average ground temperature suitable for vegetable growth is about 22°C, while in the deep winter, the inland temperature of the greenhouse is mostly 15°C-20°C. If the watering is excessive or the timing of watering is wrong, the ground temperature will drop rapidly and cause root injury. , jeopardizing the growth of the plant aboveground, therefore, watering at low temperature is best done in the morning after the grass has grown.

    3. Pay attention to moderate watering and watering at the right time

    Winter and spring greenhouse vegetables are watered, generally follow the principle of no shortage, no water, rather dry than wet, keep the water content of the rhizosphere soil of crops at about 60%, prevent excessive and frequent watering, and avoid flooding. Excessive watering can easily reduce the temperature in the shed and the soil temperature, which is unfavorable for crop growth.

    4, pay attention to control the water temperature

    When the difference between the water temperature and the temperature in the shed is more than 5 ℃, it is easy to cause root damage. Deep well water with higher water temperature or pre-storage irrigation in the shed is better.