How to prevent ammonia poisoning in greenhouse vegetables? Detailed control measures

Vegetables grown in greenhouses are highly susceptible to toxic gas damage because of insufficient ventilation, and ammonia poisoning occurs most frequently among them, so farmers should pay special attention to reduce losses. So what are the symptoms of ammonia poisoning in greenhouse vegetables? How should it be prevented? Let's take a look together.

1. Symptoms

Ammonia enters the plant body through the stomata and hydathodes. The first parts to be damaged are the most vital leaves and young buds, and the affected leaves quickly show discoloration symptoms, just as if they had been scalded by boiling water. According to field observations, if the plant suffering from ammonia poisoning is relatively large, symptoms generally start on the 2nd to 4th leaf and then spread upward and downward; if the plant is relatively small, symptoms start from the first leaf. The affected leaves show discoloration symptoms, then gradually turn yellow and scorched, until the whole plant dies.

2. Causes of poisoning

There are many causes of ammonia poisoning. Directly broadcasting urea, ammonium bicarbonate and other chemical fertilizers on the greenhouse floor produces ammonia as these fertilizers decompose, causing ammonia poisoning; applying organic fertilizer that is not fully decomposed during fertilization also releases ammonia during the decomposition and fermentation process; applying excessive amounts of chemical fertilizer and organic fertilizer also produces large amounts of ammonia; and pollution of the greenhouse environment can also introduce ammonia.

3. Preventive measures

First, fertilization should be managed with ammonia in mind. When using organic fertilizer as a base fertilizer, it must be fully decomposed; chemical fertilizer and organic fertilizer can only be applied deeply, not broadcast on the surface; and fertilization must not be excessive. In addition, the ammonia concentration in the shed should be checked. pH test paper can be used to test the pH of water droplets on the inside of the greenhouse film. When the pH value reaches 8.2 or above, ventilation must be carried out to release gas and lower the ammonia concentration. For situations where ammonia damage has already occurred, first ventilate to release gas, then water quickly to reduce the soil fertilizer concentration, and spray active liquid fertilizer on the leaves at a concentration of 1:500 to better balance the pH inside the plant and in the soil, which can alleviate the poisoning symptoms.

  The above is an introduction to preventive measures for ammonia poisoning in greenhouse vegetables. We hope it helps you. To learn more related knowledge, please keep following us.