Greenhouses are highly susceptible to harmful gases, which can significantly reduce the quality and market value of vegetables. Therefore, it's essential to monitor and manage the occurrence of these gases, especially during spring when greenhouse conditions can trap pollutants more easily.
First, let’s explore the common types of harmful gases that can affect crops:
1. **Ammonia Poisoning**
This occurs when organic fertilizers such as compost or manure are not fully decomposed, or when excessive amounts of inorganic fertilizers like urea or ammonium bicarbonate are used. During decomposition, ammonia is released, which can penetrate plant leaves, damage chlorophyll, and cause water-soaked spots, yellowing, and browning at the leaf edges. In severe cases, the leaves may wilt and die.
2. **Nitrous Acid Poisoning**
Excessive use of ammonium nitrate can prevent proper nitrification in the soil, leading to a buildup of nitrous acid gas. This causes irregular green and white spots on the affected leaves.
3. **Sulfur Dioxide Poisoning**
Common during heating, sulfur dioxide enters through leaf stomata, damaging chloroplasts and causing dehydration, white spots, and dryness. Severe cases result in entire leaves turning pale with brown veins.
4. **Carbon Monoxide Poisoning**
When using coal for heating, incomplete combustion or poor ventilation can release carbon monoxide. High concentrations lead to leaf discoloration, water-like spots, and eventually yellow or necrotic patches.
5. **Sulfite Poisoning**
Fertilizers like ammonium sulfate or unrefined cake can release sulfur dioxide, which turns into sulfite in water. This damages chlorophyll, acidifies the soil, and causes white, round, or rhombic spots on leaves.
6. **Carbon Dioxide Poisoning**
High COâ‚‚ levels inside greenhouses can cause leaf curling, starch accumulation, and deformation of chloroplasts. This affects photosynthesis and can lead to wilting. Excess COâ‚‚ also hinders oxygen absorption, disrupting normal respiration and accelerating aging.
7. **Film Gas Poisoning**
Some plastic films release volatile compounds like ethylene or phthalates under high temperatures. These can cause yellowing, whitening, and drying of leaves.
**Second, diagnosing harmful gases**
A common method to detect harmful gases in greenhouses is by testing the pH of dew formed on the leaves. For example, carbon dioxide produces acidic dew, while ammonia creates alkaline dew. Using pH test strips before morning ventilation can help identify the type and severity of gas exposure. If the pH is below 4.6, it may indicate the presence of harmful gases like ammonia, sulfur dioxide, or carbon dioxide.
**Third, prevention and control measures**
To minimize the risk of gas poisoning, it’s important to implement proper agricultural practices:
1. **Proper Fertilization**
Use well-decomposed organic fertilizers and green manures instead of chemical ones. Limit nitrogen application and avoid fertilizers containing chlorine or sulfides. When using chemical fertilizers, apply them in small quantities and at appropriate times, preferably during sunny days between 11 am and 2 pm.
2. **Timely Ventilation**
Ensure regular and adequate ventilation, especially in the early morning and during midday when temperatures rise. Even on cloudy or rainy days, short periods of ventilation at noon can help reduce humidity and remove harmful gases.
3. **Safe Heating Practices**
Avoid using coal for heating unless it is completely burned. Install chimneys to vent harmful gases and ensure proper airflow to prevent carbon monoxide or carbon dioxide buildup.
4. **Choose Safe Plastic Films**
Opt for non-toxic plastic films without harmful additives like phthalates. This reduces the risk of film gas poisoning and protects crop health.
By implementing these strategies, farmers can effectively manage harmful gases in greenhouses, ensuring better crop health and higher yields.
A feed supplement is a product that is added to an animal's diet to provide additional nutrients that may be lacking in the animal's regular feed. Feed supplements can come in many forms, including powders, pellets, liquids, and blocks, and can contain a variety of nutrients such as vitamins, minerals, amino acids, and probiotics. They are commonly used in livestock and poultry production to improve animal health, growth, and productivity. Some common feed supplements include calcium supplements for laying hens, probiotics for gut health in pigs, and electrolyte supplements for horses.
Feed Supplement,Hot Supplement Soybean Lecithin Oil,Feed Supplement Puffed Corn Flour,Supplement Soybean Lecithin Oil
Jiangsu Chenwei Biology and Technology Co. LTD , https://www.cwsoybean.com