Talking about the causes of vegetable fat damage in greenhouse

When winter arrives, greenhouse vegetables have begun to be shackled. In the past season, many crops grown in greenhouses often produce chemical fertilizers, ammonia hazards and nitrous acid gas poisoning. This is not October 11 Shandong. Sun Libin, a village in the village of Suo Miao, Jiyang County, said that he had said that his tomato had burned leaves after topdressing. When I came to Sun Libin's greenhouse to see it, I found that it was caused by improper use of fertilizer and poor management, resulting in tomato ammonia (NH3) poisoning.

Ammonia poisoning is also called ammonia gas hazard. In recent years, it often occurs in greenhouse production in winter. The ammonia poisoning hazard is divided into two types: trauma type and internal injury type. The traumatic hazard is mainly caused by damage to the leaves of the seedlings, and the leaf margin tissue turns brown first, then becomes white, and water-stained spots appear first around the leaves, and die in severe cases. The ammonia gas is immersed in the pores and water holes to damage the tissue. The ammonia poisoning that occurs after Sun Libin’s tomato topdressing is a traumatic type;

The internal injury type hazard is generally caused by a large amount of ammonium nitrogen fertilizer applied at one time, the soil solution concentration is too high, the nutrients absorbed by the vegetables are blocked, the cell permeation resistance is increased, and the reverse osmosis phenomenon is serious, the root water loss becomes brown, and the leaves turn yellow. Different vegetable varieties have different resistance to ammonia. Most vegetable seedlings are harmed when the ammonia gas reaches 5mg/L. Tomato, pepper and cabbage seedlings are sensitive, while eggplants are less sensitive to ammonia and ammonia concentration is higher. Symptoms are only indicated at 40 mg/L. Generally, the water droplets attached to the inner wall of the greenhouse or the arch shed can show the symptoms of ammonia poisoning when the pH value is above 7.2. Therefore, the test can be carried out with a pH test paper.

Because winter ventilation in the shed is poor, winter vegetables are prone to fat and gas damage. The author summarizes the reasons why farmers use fertilizer to produce fertilizers in the past few years:

1. Applying an excessive amount of ammonium nitrogen fertilizer; 2. Applying organic fertilizer such as insufficiently fermented decomposed manure and bean cake; 3. Applying urea in the shed, even using ammonium bicarbonate; 4. Drying the soil; 5 preventing wind from being timely.

Although the fat damage is not a disease, once it happens, if it is not handled properly, it can be completely destroyed in 1-2 days, and the damage caused is distressing.

Control measures: 1. Watering in time, the soil should not be too dry, keep it in a wet state, and water it when it is dry. Some vegetable farmers are controlling the seedling period, control the water over the head, and are prone to ammonia poisoning. In the seedling stage, combined with watering, the “Fugen” and the spray can be used to manage; 2. Do not apply fertilizer in the shed, apply the soil deeply, and apply water after application; 3. Apply sufficient organic fertilizer. After fermenting, apply again; 4 Do not apply ammonium fertilizer and ammonium nitrate fertilizer excessively, and apply a small amount of fertilizer; 5. Under the condition of ensuring the temperature of seedlings, open the window as much as possible to ventilate and reduce the ammonia in the shed; The occurrence of fertilizer damage, timely watering, leaf surface can spray Tianda 2116 or compound microbial fertilizer 500 times liquid or with "Fugen" 300 times liquid for root irrigation, the effect is better. Sun Libin’s tomatoes basically recovered the losses because they took the above measures in time.

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