The distribution of CO2 concentration in various parts of the facility is not uniform. Generally, the upper part of the horticultural crop is the highest in the upper canopy, the lower part is the second, and the middle is mainly the functional leaf, the photosynthesis is the most vigorous, and the CO2 concentration is the lowest. Therefore, it is necessary to perform CO2 fertilization before noon. Take the greenhouse as an example. When the skylight and one side window in the greenhouse are opened during the sunny day, the CO2 concentration in the crop growth layer is reduced to 135-150 mg/kg, which is 50-65 mg/kg lower than the upper layer of the fertility layer, and is only the atmospheric CO2 standard. About 50% of the concentration. However, on the contrary, in the evening rainy days, the concentration of C in the fertility layer is high, and the concentration in the upper layer is low. The uneven distribution of CO2 concentration in the facility will result in differences in crop photosynthetic intensity, resulting in inconsistent production and quality at various sites.
A comparison of the CO2 recorder's long-term monitoring and recording results shows that the CO2 concentration with obvious economic effects is about 5 times that of the atmosphere (atmospheric content QU30o) for general vegetables, and the optimum CO2 fertilization concentration The crop itself is related to other environmental factors. Generally, the amount of CO2 should be gradually increased with the increase of light intensity.
Using CO2 recorders to analyze carbon dioxide in greenhouse cultivation in deep winter, it can be clearly defined that the application time of CO2 must be carried out under light intensity and temperature, in order that the applied carbon dioxide can play a good role. The CO2 fertilization time in the winter greenhouse can generally be chosen at 9:00 AM. If it is in the northeastern region of China, it can be delayed appropriately. At noon, the temperature in the facility was too high and ventilation was needed. Before the ventilation, Qsh stopped. In the afternoon, it was generally not applied.
Carbon dioxide, one of the raw materials for photosynthesis of plants, under certain conditions, the photosynthetic intensity of the plant will increase with the increase of the concentration of carbon dioxide. However, under the modern facilities agriculture, especially the greenhouse agriculture, because of the closed state of protection caused by the lack of carbon dioxide content, which directly affect the yield of vegetables. Especially in greenhouse cultivation in the deep winter, it is more necessary to monitor the carbon dioxide content in the shed, and increase the gas fertilizer in order to increase the production. Carbon dioxide content in the shed can be monitored and recorded using a CO2 recorder.