Common carbon dioxide fertilization methods include increasing the application of organic fertilizer, using CO2 generators, liquid carbon dioxide fertilization, and using sling-type carbon dioxide gas fertilizer.
The greenhouse has strong airtightness. In order to keep warm and store heat in the severe winter, the ventilation coefficient is small and the time is short, resulting in a lack of carbon dioxide in the greenhouse, which affects plant photosynthesis. Experiments show that the use of carbon dioxide gas fertilizer technology after removing the straw and before ventilation can generally increase the yield by 20-30% per mu. The reason is that the highest concentration of carbon dioxide in the greenhouse is in the morning before the straw is removed, and the general concentration can reach 1400-2500PPM. After removing the straw, as the photosynthesis of vegetables proceeds, the carbon dioxide concentration in the greenhouse drops sharply. By 8-9 o'clock, it is only 150-200PPM, and it will be even lower if ventilation is not timely. Even with ventilation, the carbon dioxide concentration can only be supplemented to 300PPM. Vegetable crops are still in a state of carbon dioxide starvation. If vegetables are in this state for a long time, their normal growth and development will be seriously affected, resulting in reduced nutrient accumulation, weak plant growth, poor root development, and accelerated aging, which will directly affect the yield and quality of vegetables and reduce economic benefits.
Common carbon dioxide fertilization methods in production are mainly the following:
1. Increase the application of organic fertilizers. The large-scale application of organic fertilizers in the soil can not only provide vegetables with necessary nutrients, meet growth needs, and improve the physical properties of the soil, but also the decomposition of organic matter releases a large amount of carbon dioxide, which is beneficial to the photosynthesis of vegetables.
2. CO2 generator method. The CO2 generator method is a method of generating CO2 by reacting sulfuric acid with carbonates. In a 667m2 greenhouse, adding about 3.6kg of ammonium carbonate to sufficient sulfuric acid every day can make the CO2 concentration reach 1000mg/L. The specific method is: set up 30 containers of sulfuric acid in the greenhouse. Generally, plastic barrels are suitable, not metal containers. Hang the barrels in a space that does not affect field operations, and the height is flush with the height of the vegetable plants. Dilute 98% industrial sulfuric acid in the ratio of acid and water at 1:3. Do not pour water into the acid to avoid splashing and damaging crops.
Pour 0.5kg of dilute acid into each barrel, add 100g of ammonium carbonate to each barrel every day, and generally add acid once for three days of ammonium carbonate. If there is no bubbling after adding ammonium carbonate, it means that the dilute acid reacts completely and the remaining solution is removed. The removed ammonium carbonate sulfate mixture is diluted with 80-100 times of water and sprayed on vegetable leaves, which can not only effectively promote the growth of vegetables, but also effectively prevent and control diseases and pests.
3. Liquid carbon dioxide fertilization method. The sources of liquid carbon dioxide are mainly brewing industry, chemical industry by-products, air separation, underground storage, etc. The liquid carbon dioxide gas source is relatively pure, does not contain harmful substances, is easy to apply, and is safe and reliable to use, but the cost is relatively high.
4. Combustion method. Carbon dioxide is produced by burning liquefied petroleum gas, propane gas, natural gas, white kerosene, etc. through a carbon dioxide generator. This method is easy to use and easy to control.
5. Application of granular organic biogas fertilizer method. The granular organic biogas fertilizer is evenly applied between the plant rows at a certain interval, with an application depth of 3 cm, and the soil in the acupoints is kept with a certain amount of moisture, so that its relative humidity is about 80%, and soil microorganisms are used to ferment and produce carbon dioxide. This method is easy to use and safe, but the storage conditions are extremely strict. The speed of carbon dioxide release is affected by temperature and humidity, and it is relatively difficult to control.
6. Hanging bag carbon dioxide gas fertilizer fertilization method. Hanging bag carbon dioxide gas fertilizer is in the form of a powdery solid, consisting of a generator and a promoter. The generator is 110g per bag and the promoter is 10g per bag. Mix the two and stir them evenly, poke a few small holes in the bag, and the CO2 in the hanging bag is continuously released from the small holes for the plants to absorb and utilize. Hang the small bag containing CO2 accelerator and generator at about 40-1500px above the branches and leaves of the plant. You can fix the thin wire on both sides of the trellis and hang it in the middle. If you plant apricot, peach, grape and other fruit trees in the trellis, the hanging bag can be hung on the dense functional leaves of the upper part of the fruit tree trellis. Each bag of gas fertilizer has a use area of about 30m2, and about 22 bags can be hung per 667m2. The effective period of CO2 gas fertilizer is about 30d. The release of CO2 increases with the increase of light and temperature. When the temperature is too low, the release of CO2 is less.
7. Apply solid CO2 gas fertilizer. Solid CO2 gas fertilizer is brown flat particles or discs, with good physical properties, stable chemical properties, safe use methods, and long fertilizer effect. The specific fertilization method is to dig trenches between rows and spread them before the vigorous growth period of crops. Put a tablet every 750px, and then cover the soil with 2-75px to keep the soil loose, which is conducive to the release of CO2 gas.
Generally, 30-40kg per 667m2 can make the CO2 concentration in the greenhouse reach 800-900mg/L, with an effective period of 60-80d and a high efficiency period of about one month. It is advisable to ventilate the middle and upper parts after fertilization. Organic CO2 gas fertilizer contains rich trace elements necessary for plants such as C, N, P, K, etc. After use, it slowly releases CO2 at a certain temperature to meet the needs of plant photosynthesis, thereby improving photosynthetic efficiency.
