What are the preventive measures for ammonia poisoning in greenhouse vegetables?

Vegetables grown in greenhouses are highly susceptible to toxic gas damage because ventilation is poor, and among these, ammonia poisoning occurs most frequently, so farmers must 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 to be damaged are the most vital leaves and young buds. Affected leaves quickly show discoloration symptoms, 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 begin on the 2nd to 4th leaves and then spread upward and downward; if the plant is relatively small, symptoms begin from the first leaf. Affected leaves show discoloration symptoms, then gradually turn yellow and scorched, until the entire plant dies.

2. Causes of poisoning

There are many causes of ammonia poisoning. Directly broadcasting chemical fertilizers such as urea and ammonium bicarbonate on the greenhouse floor produces ammonia as these fertilizers decompose, causing ammonia poisoning; applying incompletely decomposed organic fertilizer 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 in the greenhouse environment can also introduce ammonia.

3. Preventive measures

First, fertilize in a way that avoids ammonia. 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 greenhouse 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 reduce the ammonia concentration. For situations where ammonia disinfection has already occurred, first ventilate to exhaust the gas, then water quickly to reduce the soil fertilizer concentration, and spray an active liquid fertilizer on the outside of the roots 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 the preventive measures for ammonia poisoning in greenhouse vegetables. We hope it helps you. If you want to learn more related knowledge, please follow us.