Greenhouse Vegetable Cultivation Technology

Plastic greenhouse vegetable cultivation often causes excessive toxic gases in the greenhouse due to improper fertilization methods and neglect of ventilation, which harms vegetables and is often misdiagnosed as diseases, resulting in poor or even total harvest.

 Hazards:

1. Nitrogen Due to excessive application of quick-acting fertilizers such as urea and thiourea sulfate, or improper fertilization methods, such as the application of uncomposted organic fertilizers, ammonia is produced by decomposition under high temperature conditions in the greenhouse, which will harm vegetables and cause water-soaked spots on the leaf margin tissue. In severe cases, the entire leaf wilts and dies. It is often misdiagnosed as frost disease or other diseases. Vegetables that are sensitive to ammonia include cucumbers, tomatoes, zucchini, etc.

2. Nitrite gas Excessive application of ammonium nitrogen fertilizer at one time will reduce the effect of certain bacteria and cause local acidity in the soil. When the pH value is less than 5, nitrite gas is produced, which can cause white spots on vegetable leaves, and in severe cases, the entire leaf turns white and dies. It is often misdiagnosed as powdery mildew. Vegetables that are sensitive to nitrite gas include eggplant, cucumber, zucchini, celery, pepper, etc.

3. Ethylene and chlorine If the quality of agricultural film or ground film is poor, or there is ground film residue in the ground, it is easy to volatilize and produce harmful gases such as ethylene and chlorine under the high temperature conditions in the greenhouse. When the concentration reaches a certain level, the edges or veins of vegetables can turn yellow, and then turn white. In severe cases, the whole plant will die. It is often misdiagnosed as bacterial angular leaf spot, which is particularly harmful to cucumbers.

In addition, heating in winter will produce toxic gases if the fuel is not burned fully, and untimely ventilation will cause excessive accumulation of carbon dioxide. Affect vegetable production.

Prevention:

1. Reasonable fertilization. The organic fertilizer applied in the greenhouse must be fermented and humidified, the chemical fertilizer must be of high quality, and urea should be mixed with superphosphate calcium. The base fertilizer should be applied 20 cm deep, and the topdressing fertilizer should be applied to a depth of about 12 cm. Water in time after application.

2. Ventilation. In sunny and warm weather, ventilation should be carried out in combination with temperature adjustment, and ventilation should also be carried out appropriately in rainy and snowy weather.

3. Choose safe and non-toxic agricultural films and ground films, and remove waste plastics and their residues in the greenhouse in time.

Technology for applying carbon dioxide to greenhouse vegetables