As a rule, co2 in air is 300-330 ml/m3, which can significantly improve the yield and quality of many crops if the concentration increases to 800-1,000 ml/m3 during crop growth. Co2 deficiency has become the least controllable environmental factor limiting crop growth and development. It is therefore necessary to apply co2 to increase light efficiency and hence production and quality in greenhouse cultivation, especially in the mornings of the expansion and harvest of fruit and fruit. The main methods of co2 fertilization are solid co2 (dry ice), liquid co2 (steel bottles), combustion, co2 solid particulate fattening, chemical reaction and straw biological reactors。
The main ones that are most suitable for use by farmers are co2 solid particulate fattening, chemical reaction and straw biological reactors。
(1) co2 solid particulate fattening
Compost (ammonium carbonate) is fed directly into a holed plastic bag or is distributed directly to the ground, and photoheated to decomposition to co2. Since the gas process is a natural release process, insufficient releases result in less manageable and effective releases。
(2) chemical response law
The use of rare sulphate or rare phosphate and ammonium carbonate fertilizer reacts when co2 is required in greenhouses, producing co2 for plant growth, which can be provided when vegetable growth is needed. However, since sulphuric acid is highly corrosive, it is safer to use phosphate when used。
(3) stifling biological reactors
The built-in straw reactor is a plant that embeds the straw in the planted soil and inserts a pipe that provides plant growth to co2 from the decayed straw。
External straw reactors typically build reaction pools with a size of 5 m x 1 m x 1 m (long x wide x depth) in a shed of 50 m x 8 m, internal straws, closed with plastic membrane treatment, natural decomposition and fermentation using the hot temperature of greenhouses, and co2 from composting can significantly increase co2 concentrations in greenhouses by blowing fans to vegetable crops. The advantages of this approach are that co2 is from a wide range of sources, low cost and easy to control; the disadvantages are that it is land-possessed and that the gaseous content and environmental impacts are high。
The increase of co2 during the harvest period has had a significant impact on the increase in vegetable production, which is usually applied between 1 and 2 times a week in the morning, and not for too long. Fertilizers are usually applied at 9-10 a. M. Every morning after sunrise, before the wind cools when photolytics are consumed to normal concentrations after two hours, and co2 application is stopped half an hour before the break。
