Vegetable greenhouse planting technology is a common technology, which has good thermal insulation performance, can eat out-of-season vegetables at any time, and is deeply loved by people. A greenhouse style commonly used for growing vegetables is a solar greenhouse with columns. There are many rows of columns in this greenhouse, which strengthens the stability of the whole greenhouse and greatly improves its ability to resist pressure and snow.
I. Matters needing attention when watering vegetables in greenhouses
Reasonable watering is an important measure to ensure the healthy growth and increase the yield of vegetables in greenhouse. In winter, the temperature is low, and the watering of greenhouse vegetables is different from other seasons. It depends on both the weather and the situation of seedlings to avoid side effects. According to experience, the following four measures should be taken to water vegetables in greenhouses:
1. Appropriate watering time The watering of greenhouse vegetables in winter should be arranged around noon, preferably after 10 in the morning and before 3 pm. During this period, the greenhouse temperature is high and the side effects are minimal after watering. Avoid watering in the morning and evening to avoid freezing injury to vegetables. Well water should be used as much as possible for watering, because the temperature of well water is high, which can reduce the physiological stimulation to vegetables.
2. Flexible watering according to the weather: According to the weather conditions, master the principle of "properly watering more on sunny days, less or no watering on cloudy days, and never watering on snowy days". When the weather turns from sunny to cloudy, the amount of water should be gradually reduced and the interval should be appropriately lengthened; When it turns from cloudy to sunny, the amount of water changes from small to large, and the interval time changes from long to short accordingly.
3. Watering should be focused on: the temperature of different parts of the greenhouse is quite different, and the watering amount should also be different. In the south of the greenhouse and near the heat sources such as stoves and flues, the soil moisture and evaporation near it are large, and the watering amount can be appropriately larger; The temperature in the east, west and north of the greenhouse is low, the sunshine time is short, and the watering amount should be less.
4. Shallow water should not be too large. At low temperature, the vegetables in the shed evaporate slowly, and the water demand is reduced accordingly. Therefore, the watering amount should be small and the interval should be appropriately long. It is advisable to avoid flooding with water, and watering or spraying should be used to avoid vegetable retting caused by low temperature and high humidity. In the first two days after watering, it is easy to cause the humidity in the shed to increase, so we should pay attention to reasonable ventilation and cooling to prevent diseases. Ventilation is generally appropriate when the temperature is high at noon.
Second, the greenhouse vegetable fertilizer and water management technology
Organic fertilizer should be applied to greenhouse vegetables. Organic fertilizer can improve soil structure, enrich soil microorganisms and increase soil fertility, fertilizer supply and livestock water capacity. Moreover, it is necessary to give priority to base fertilizer and apply 5000 kilograms of decomposed organic fertilizer per mu, which is convenient for future production management and reduces or avoids the harm of secondary salinization of soil in the shed. When using chemical fertilizer, we should pay attention to deep application, and don't overdo it at one time. No fertilizer is allowed to be applied on the surface in the shed. After mastering the above principles of fertilization, producers can apply topdressing according to crop types, different growth stages and individual growth conditions. If topdressing is applied in low temperature season, it should be done at noon on a sunny day, and ventilation should be conducted for 1~2 hours after topdressing until the water on the leaves is dry. Where conditions permit, carbon dioxide fertilization can be carried out to increase yield.
Drip irrigation is better for vegetables in greenhouse, which can not only save water, but also reduce the humidity in greenhouse. If there is no drip irrigation facility, it can also be irrigated or furrowed. Try not to furrow irrigation in low temperature season, and water should be done at noon on sunny days. After watering, open the shed for ventilation, and it is best to combine irrigation with topdressing. If the soil in the shed is very dry and furrow irrigation is really necessary, furrow irrigation can only be carried out after continuous fine weather. When furrow irrigation, water can't flood the border.
Third, how to prevent weak light in greenhouse vegetables
In winter and spring, vegetables cultivated in plastic greenhouses often suffer from weak light damage (referred to as "weak light disease") because of insufficient light. The general symptoms are: poor plant growth and soft stems; Leaves are thin, light in color and easy to yellow; Poor flower bud differentiation, abnormal floral organs and serious flower and fruit drop; The fruit grows slowly, is light in color, astringent in taste and poorly colored. Weak light syndrome has certain influence on the yield and quality of vegetables.
Preventive measures: mainly to improve the lighting conditions in the shed as much as possible. When planting, appropriately increase the row spacing between plants and reduce shading between plants. Keep the shed film clean to prevent water drops and dust from adhering to the film surface. In the middle and late period of vegetable growth, when the temperature outside the film reaches 15℃ around noon, part of the film should be properly uncovered to let the sunlight directly enter the shed. In addition, according to the experiment, a reflective curtain with a width of 2m and a length of 3m is spliced by aluminum-plated polyester film, which is hung on the upper end of the rear column in a plastic greenhouse (or greenhouse) and the lower edge hangs to the ground, so that the ground light can be increased by 40%_43%, the greenhouse temperature can be increased by three or four degrees Celsius, the ground temperature can be increased by 1.8℃_2.9℃, and the tomato yield can be increased by 4/kloc-0. Laying silver gray film or aluminum foil on the ground can also increase the light intensity between plants, make the fruit well colored, and effectively prevent the premature aging of the lower leaves.
4. What should we pay attention to when building vegetable greenhouses?
1. The durability of vegetable greenhouses must be considered. The durability of greenhouse is affected by the aging resistance of greenhouse materials and the bearing capacity of greenhouse main structure. In addition to its own strength, the durability of light-transmitting materials is also manifested in the continuous attenuation of light transmittance over time, and the attenuation degree of light transmittance is a decisive factor affecting the service life of light-transmitting materials.
2. Pay attention to thermal insulation performance when building greenhouses. Improving the thermal insulation performance of greenhouse and reducing energy consumption are the most direct means to improve the production efficiency of greenhouse. The insulation ratio of greenhouse is a basic index to measure the insulation performance of greenhouse. The insulation ratio of greenhouse refers to the ratio of the covering area of transparent materials with small thermal resistance to the sum of the covering area of greenhouse envelope with large thermal resistance.
3. The greenhouse construction needs good light transmission effect. Light transmittance is the most basic index to evaluate the light transmittance of greenhouse. Light transmittance refers to the percentage of the amount of light penetrating into the greenhouse and the amount of outdoor light. The light transmittance of greenhouse is influenced by the light transmittance of light-transmitting covering materials and the shadow ratio of greenhouse skeleton, and it changes at any time with the different solar radiation angles in different seasons.
Five, greenhouse vegetables after freezing measures
During the period of planting vegetables, sometimes vegetables are frozen, which requires some remedial methods to make vegetables grow normally.
1. artificial water spraying: water spraying can increase the air humidity in the shed, stabilize the shed temperature, and inhibit the evaporation of water from the frozen tissue, thus promoting the tissue to absorb water.
2. Irrigation and heat preservation: Irrigation can increase the soil heat capacity, prevent the low temperature from dropping, and stabilize the atmospheric temperature close to the ground surface, which is conducive to the steady rise of the temperature and restore the function of the frozen tissue.
3. Outdoor cooling: After the vegetables in the greenhouse are frozen, the greenhouse cannot be closed immediately to raise the temperature, only outdoor cooling can be used to make the temperature in the greenhouse rise slowly, so as to avoid the frozen tissue from necrosis due to the rapid temperature rise.