strawberry greenhouse requirement
1. Greenhouse environmental indicators suitable for strawberry growth.
1. Temperature: The highest temperature during the day shall not exceed 30℃, and the lowest temperature at night shall not be lower than 5℃.
2. Lighting: Keep indoor light transmittance high. From January to February, when the temperature is low and there is little sunlight, you can increase the lighting time by supplementing light. From May to June, when the light intensity is high, you should shade and cool down in time.
3. Humidity: When the temperature in the greenhouse exceeds 30°C and the outside temperature is no less than 2°C, natural ventilation should be carried out as much as possible; during the flowering period, the relative humidity during the day is best controlled at 40% ~ 50%, and the substrate humidity is preferably maintained at 50% ~ 60%.
4. C O2 concentration: During the low-temperature and low-light season, a self-made simple device for increasing C O2 is placed in the greenhouse to increase the indoor C O2 concentration through the fermentation of organic waste to make up for the C O 2 deficit in the greenhouse at this stage to increase strawberry yield.
2. Selection and control of temperature indicators
1. Temperature requirements
Strawberry is a crop with strong adaptability to temperature. It likes temperature but is not resistant to high temperature, and has a certain degree of cold tolerance.
(1) The optimal temperature for the growth of strawberry seedlings is 18℃~23℃.
(2) The optimal temperature for rhizosphere growth is 8℃~21℃.
(3) The most suitable day temperature for fruit enlargement is 18℃~20℃.
(4) The optimal temperature for pollen germination is 25℃~27℃.
(5) Temperatures below 0℃ or above 40℃ during the flowering period will cause pollination obstacles, affect seed development, and lead to deformed fruits.
(6) The optimal temperature for photosynthesis is 15°C~25°C. When the temperature rises to 20°C~25°C, the photosynthetic rate reaches a peak; when the temperature is lower than 15°C or exceeds 30°C, the photosynthetic rate of the leaves decreases significantly and plant growth is inhibited.
2. Selection and management of temperature indicators
Based on cultivation experience, the temperature control index is set to not exceed 30℃ in the morning and not lower than 5℃ at night.
In spring and autumn, glass greenhouses can make use of natural temperature and light, ventilation, and internal and external shading systems to control the temperature at an optimal state, especially
In September and October, sometimes the daytime temperature is still very high, and the temperature can also be controlled through a fan wet curtain cooling system. The temperature in the glass greenhouse during the day should not be higher than 30°C, and the temperature at night should be reduced as much as possible. When the temperature of the glass greenhouse is above 25°C during the day, ventilation, shading and cooling must be carried out in time. If the temperature is not ventilated in time and the temperature reaches above 35°C or the night temperature exceeds 13°C, it will cause the axillary flower buds of strawberry to degenerate, hinder the development of male and female stamens, and produce a large number of grape stems, consuming a lot of nutrients and resulting in reduced yields.
During the low temperature period in winter, according to the temperature requirements of the strawberry growth stage, the glass greenhouse uses sunlight to naturally heat up during the day and pays attention to proper ventilation. The temperature is generally controlled at 22~25°C. When the outside temperature is below 0°C, close doors, windows and thermal insulation curtains in the evening. At the same time, cover the interior walls of the greenhouse with a layer of film to reduce the exchange of hot and cold air in the gaps around the doors and windows and play a role in thermal insulation. The nighttime temperature of the glass greenhouse should be controlled at -10~2℃, with 5~7℃ being the best. Try to store some heat to maintain the temperature during the nutrient conversion and transportation period. Generally, the lowest temperature for the onset of strawberry anthracnose is 10~15℃, so controlling the night temperature at 5~7℃ is within the buffer range that does not affect the normal growth of strawberries. It can effectively control the occurrence of major diseases such as anthracnose. The effect is obvious, and it is also conducive to the enrichment of strawberry fruits and the maintenance and improvement of sugar content.
3. Lighting management measures
Strawberry is a light-loving plant, and light is an important factor for strawberry survival. Only under sufficient light conditions can strawberry plants grow robustly, flower buds are well differentiated, and berries can produce high yields and high quality. Different stages of strawberry growth have different requirements for light conditions. During the flower bud formation period, short days of 10 to 12 hours and lower temperatures are required; during the flowering and fruiting stage and vigorous growth period, longer days of 12 to 15 hours are required.
The light saturation point of strawberry leaves is 20,000 to 30,000 lx, and the light compensation point is 0.5 to 10,000 lx. Under different CO 2 concentrations, the light saturation point and compensation point will also change accordingly. In winter, when strawberries enter the continuous flowering and fruiting stage, they often encounter low temperatures and little light, and are prone to insufficient light. It has been determined that the light intensity in the glass greenhouse strawberry field is unevenly distributed. When the light intensity is 20,000 lx at noon on a sunny day in winter, the light intensity under the strawberry bushes is 0.5 to 10,000 lx lower than the strawberry photosynthesis compensation point. On rainy days, the indoor light intensity is only 0.2 to 0.4 million lx [4]. The strawberry pedicels and petioles become slender, the leaf color becomes pale or yellow, the flowers and fruits are small, the fruit surface is light red or white, the taste is bland, the sweetness and sourness are insufficient, the quality becomes poor, and the maturity period is delayed.
When cultivating strawberries, they must be planted reasonably densely to maintain high indoor light transmittance. According to data, strawberry plants have different leaf ages.
The photosynthetic ability of leaves varies. The effective leaf age for photosynthesis is 30 to 50 days. The photosynthetic ability of the 3rd to 5th leaves from the heart leaf is the strongest. The photosynthetic ability of the leaves after the 7th leaf decreases significantly and should not be retained. They should be removed in time to keep the leaves sparse and not block light from each other. Maximize the lighting time. If necessary, reflective film, lime coating or artificial supplementary light can be laid in the glass greenhouse to facilitate the normal growth and development of strawberries and promote flowering and fruiting.
Especially in the later stages of berry development, supplementary light can significantly increase the soluble solids content of the fruit and ensure the flavor of the fruit. During May-June and September-October, the light intensity is very high and the sunshine time is long. The glass greenhouse causes high temperatures due to the photothermal effect. It should be shaded and cooled in time to prevent sunlight from burning the strawberry plants.
4. Humidity control requirements
During the winter heat preservation period, the relative humidity of the air in the glass greenhouse will be too high. Try to take comprehensive measures to reduce the humidity, such as elevated cultivation and drip irrigation under the nutrient solution film. If conditions permit, a nutrient solution recovery system can be added to reduce ground evaporation. At the same time, old yellow leaves of the plants should be removed in time, and excess secondary flowers, fruits, grape stems, etc. should be removed. When the temperature in the glass greenhouse exceeds 30°C, natural ventilation should be carried out in time, and the outside temperature should not be lower than Under the condition of 2℃, try not to close the skylight at night and use natural ventilation as much as possible to reduce the relative humidity of the air. At the same time, be sure to close the insulation curtain film to prevent the plants from being directly affected by cold air and causing freezing damage.
During the flowering period, the relative humidity during the day is best controlled at 40% to 50%. Too high or too low relative humidity is not conducive to strawberry pollen germination. The substrate humidity control is based on the principle of "wet but not waterlogged, dry but not drought", and the moisture content of the substrate is judged based on the water spitting out of the strawberry leaves in the early morning. It is advisable to maintain a moisture content of 50% to 60% in the substrate. Too much or too little moisture content will affect the vitality of the strawberry root system and the normal growth and development of the fruit.
In summer and autumn, the fan wet curtain cooling system is mainly used to increase indoor relative humidity, which is beneficial to the survival of plants and seedlings. On rainy days, fans are used to drain moisture and cool down. The humidity in the greenhouse should be reduced as much as possible during the entire growth period of strawberries to reduce the occurrence of pests and diseases.
5. Fermentation of organic waste to increase application of C O2 CO 2 is an important raw material for photosynthesis of plants. Within a certain range, as the CO 2 concentration increases, both the light saturation point and the photosynthetic rate increase. The application of CO 2 gas fertilizer in facility cultivation is one of the important measures to improve plant photosynthesis. There is insufficient light in the greenhouse. After applying CO 2 gas fertilizer, the plants grow vigorously and the yield is approximately 1.5 times that of the control. The yield increase effect is significant.
During the low-temperature and low-light season from January to February, a patented CO 2 device is placed in the greenhouse to increase the indoor CO 2 concentration through organic waste fermentation, making up for the CO 2 deficit of strawberries in the glass greenhouse at this stage, and at the same time increasing strawberry yield.
Specific measures to increase the application of CO 2 in the glass greenhouse: Place 2 sets of CO 2 gas fertilizer devices in a glass greenhouse with an area of ??1992 m 2 . The devices can supplement CO 2 gas fertilizer before 9:00 on a sunny day from December to February of the following year. The appropriate concentration is 0.07% to 0.1%. However, if it is applied when there is sufficient sunshine, the indoor temperature in a frequently closed greenhouse will be too high, which will actually reduce the photosynthetic rate.