Reduce humidity and inhibit disease
After the shed, the temperature in the facility is relatively high, and at the same time, a high-humidity environment is easily formed, and high temperature and high humidity create favorable conditions for the occurrence and spread of diseases.
During production, the following measures can be taken to reduce the humidity in the shed. Of course, the combination is better.
1. Cover with non-drip film
Due to the difference in temperature inside and outside the shed, condensation of the shed film is inevitable. Condensation on the surface of ordinary plastic film is evenly distributed, so the dripping surface is large and the air humidity increases.
After the non-drip film is used, although the surface is dew, water drops flow down the surface of the film, the dripping surface is small, the humidity is significantly reduced, and the light transmission performance is good, which is beneficial to increase temperature and reduce humidity.
2. Cover with mulch
The use of mulching film can reduce the evaporation of soil moisture, and can reduce the number of irrigation times, which is an important measure to reduce the indoor air humidity in the shed.
For example, the small and large ridges are alternately spaced in the shed, and the mulching film covers the double ridges, and the water flows along the small ridges under the mulching film.
The mulch film prevents the evaporation of water, and also prevents the air humidity in the shed from increasing greatly after watering.
3. Reasonable dense planting
The planting density in the shed should not be too dense to facilitate ventilation and reduce air humidity.
4. Ventilation
Ventilation is the main measure of dehumidification. It should generally be carried out around noon when the temperature is high. The top wind and waist wind are the main ones, and the bottom wind cannot be used to prevent the shed room temperature from being too low and "sweeping wind" injuring seedlings.
If the humidity in the shed stays high and the temperature is above the lower limit of the optimum temperature for crop growth, the ventilation should be gradually increased, and the air humidity should be reduced as soon as possible, but the cooling caused by ventilation should be based on the premise that the crop does not cause chilling damage.
5. Water reasonably
Watering is the main factor leading to the increase of humidity in the shed. The frequency of watering and the amount of watering each time should be determined according to the weather, soil conditions, vegetable types, growth period and growth potential. Generally, small water should be watered or ditch-wheeled watering, and flooding should not be avoided.
The planting water and slow seedling water of fruits and vegetables should be watered thoroughly, and water should be sufficient in the fruiting period, and watering is generally not required in other periods.
When the temperature in the shed is low, especially when ventilation is not possible, watering should be controlled as much as possible. Generally, it can be watered from 10 to 12 o'clock in the morning on a sunny day, with ventilation and moisture removal.
When conditions permit, furrow irrigation or drip irrigation under the film can be used to reduce irrigation and evaporation.
6. Strengthen cultivating soil loosening
After planting, before covering with mulch, and after watering, it can be cultivated to loosen the soil in time, which can reduce evaporation, maintain soil moisture, reduce watering times, and reduce air humidity.
7, heating and dehumidification
Every time the temperature in the shed rises by 1℃, the relative humidity in the air drops by 3% to 5%. The method of heating and dehumidifying can not only meet the temperature needs of vegetables, but also reduce the relative humidity of the air.
When the plant has passed the seedling stage and the resistance is slightly stronger, watering and closing the shed will heat up to about 30°C for 1 hour, and then ventilate and dehumidify. It can be repeated once when the shed temperature is lower than 25℃ after 3 to 4 hours.
8. Change medication
Vegetable farming medicine is mainly spray, which is bound to increase the humidity in the shed. It is recommended that when spraying on a sunny day, ****** should be done at about 3 in the afternoon, and try to finish spraying before dark to ensure that the liquid is completely absorbed.
In the case of continuous cloudy days, vegetable farmers can choose automatic spraying machines and misting machines to reduce the amount of medicine.
If conditions permit, the dust method and smoke method are used to avoid increasing the air humidity in the shed and improve the control effect.
9. Reduce ineffective transpiration
In the middle and late stages of greenhouse vegetable production, plant transpiration is the main source of indoor water vapor. Agronomic measures such as timely trimming of vines, topping, removal of dead leaves, and removal of vulnerable plants must be taken to improve the plant population structure and reduce plant inefficiency. Transpiration.
Increase temperature and light, promote growth
As the outside temperature decreases, the temperature inside the shed also gradually decreases, especially when the soil temperature is low, which will cause the growth of crop roots to be hindered, the absorption capacity becomes poor, and the plant's stress resistance also deteriorates.
Therefore, daily management must do a good job of heat preservation, and when necessary, measures must be taken to increase temperature and supplement light to ensure healthy crop growth.
1. Multi-layer covering insulation
When the outside temperature is low, multi-layer covering can be adopted for heat preservation. Greenhouses generally use three-layer coverage, and some have to cover the ground.
The three-layer covering is one layer of shed film, one layer of second film and one layer of small shed film. Three-layer coverage generally makes the lowest temperature in the shed higher than the lowest night temperature at night by about 4.5°C. At night, the small shed is covered with straw curtains, which has good heat preservation, but the operation is more labor-intensive.
Ground coverage can increase soil temperature and reduce humidity in the shed. The method of spreading mulch on the border surface and spreading straw in the border ditch is low cost and *********.
2. Add wall insulation layer
Specific method: use ordinary agricultural film or old film, cut into a long width of about 3 meters, film length = greenhouse length + gable length, and then heat the two ends of the film with an iron, and bond them into a seam tube of about 10 cm. Insert a 3-meter long wooden stick, pull it apart, and tighten it to wrap the back wall and gable.
The wooden sticks at both ends are plunged into the soil on the ground at a depth of more than 30 cm. The upper ends are tied with iron wire and fixed on the outer edge of the gable wall. The bottom edge of the film is buried in the soil outside the wall. Then fill the gap between the wall and the film with grass, with a thickness of about 30 cm, and then use soil to bury the upper edge of the film on the back slope of the greenhouse.
By adopting this method, the wall heat is no longer radiated outwards, and the night temperature in the greenhouse can be greatly increased, and the effect of stabilizing the night temperature in the severe cold period is obvious.
3. Use straw bioreactor to increase temperature
Dig a trench with a width of 60-70 cm and a depth of 25-30 cm according to the size of the cultivation border, fill it with straw, and place a special microbial agent. Cover the straw with soil about 20 cm, and irrigate until the straw can be poured.
Straw can be gradually decomposed under the action of microorganisms and release heat and carbon dioxide. This measure can increase the soil temperature of the root layer by about 2°C, improve the physical structure of the soil and the ecological environment, and supplement carbon dioxide for crops.
4. Ignition heating
If it is hit by a strong cold current and the indoor night temperature is below 6°C, ignition is required to increase the temperature.
The method is to ignite biogas in the facility, and set up a biogas stove for every 60-meter-long greenhouse, pass in the biogas, and ignite it to increase the temperature.
If there is no biogas equipment, several briquettes can be placed in the shed. However, attention should be paid to prevent carbon dioxide poisoning, and the greenhouse should be ventilated first before entering people.
Never ignite wood chips, grain chaff, etc. in the shed to increase the temperature. Ignite these substances in the closed environment of the shed. It is easy to produce toxic gases such as carbon monoxide and cause safety accidents.
If conditions permit, you can also use electric heating lines, boilers or ground source heat pumps for heating, but generally only modern facilities or seedling greenhouses will be used.
5. Apply warming and fertilizing combustion block
The temperature-increasing fertilizer combustion block is a new product used to increase the temperature and carbon dioxide concentration in the shed. It is easy to use and has obvious effects. Each greenhouse costs 18-30 yuan per day.
Instructions:
Use 6-9 pieces per mu of greenhouse or large shed, or use 1 piece per 300 cubic meters of shed space, divided into 3 to 4 places for lighting. Light it 1 to 2 hours before pulling the grass thatch in the early morning, and each piece can burn for about 50 minutes.
When in use, draw a match and place it next to the vent of the burning block, and the burning block can be ignited by inclining the sealing wax. Put the matching screen on two standing bricks with a height of not less than 15 cm from the ground, and it will ignite The burning block is placed on the screen, and the burning block is covered with a matching suction tube, which is conducive to burning and increasing heat.
Precautions:
Do not lay it flat on the ground, ignite it on the walkway of the shed, and stay away from flammable materials such as shed film. The shed must be ventilated during continuous use to prevent excessive indoor carbon dioxide from causing harm.
People should not enter the shed as much as possible after lighting. The use of greenhouses for growing fruits should be prohibited during the flowering period. The use of sheds for growing tomatoes should be reduced to prevent fumigation of leaves.
6, Yuba heating
It is also possible to install the bulb for heating the bathroom above the crop in the shed, and use the heat energy of the bulb to increase the temperature in the shed.
Generally, each greenhouse is equipped with 10-15 Yuba bulbs with a power of 275W, which can increase the indoor temperature by 2 to 4°C. The hanging height is 1.5 to 2 meters from the ground. Turn on in the early morning and morning, and at night when the indoor temperature cannot meet the growth requirements.
Pay attention to the use of waterproof lamp sockets, and also consider the electrical load to avoid accidents.
7. Apply fill light
In the case of continuous cloudy and rainy and snowy days, when there is insufficient light in the shed, you can also install a fill light.
Under the condition of sufficient sunlight, the yield of general melons and fruit vegetables can increase by 20%~30%, and the yield of leaf vegetables can increase by 30%~50%.
The effective lighting radius of each lamp is about 2 meters, and the hanging height is 1.5~2 meters from the ground, and more than 1 meter from the growing point of the crop. The distance between each lamp is about 3 meters for tomato, cucumber and other fruits and vegetables. The spacing is about 4 meters.
Waterproof lamp sockets are required, and timers can be installed if conditions permit, which can accurately control the switching time. Fill up the light all day on a cloudy day, and fill up the light for 3 to 4 hours after the grass thatch is placed on a sunny day. Ensure that the daily light time is about 10 hours.
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