Ammonia burn

Ammonia burn is a physiological disorder in plants caused by excessive concentrations of free ammonia (NH3) within the plant tissues or the root zone. Unlike biotic diseases, this condition is non-infectious and arises from chemical toxicity, often linked to improper fertilization practices or environmental stressors.

The condition affects a wide range of agricultural crops, including vegetables in greenhouses, fruit trees, and various field crops. Seedlings and young plants are particularly susceptible due to their high metabolic rates and underdeveloped root systems, which lack the capacity to buffer high nitrogen influxes.

The biology of this disorder involves the disruption of cellular integrity. Ammonia penetrates plant cells and interferes with photosynthesis and carbohydrate metabolism, causing a sudden collapse of tissue structure. This leads to the characteristic browning or whitening of leaf edges as cells die due to chemical toxicity.

Development and spread are favored by conditions such as applying high rates of ammonium-based fertilizers in cold or poorly aerated soils, insufficient watering after fertilization, and high greenhouse temperatures that facilitate the volatilization of ammonia gas from the fertilizer granules.

The impact of ammonia burn is significant, resulting in reduced photosynthetic area, stunted development, and potential yield loss. Control and prevention strategies focus on balanced fertilization, ensuring proper deep placement of fertilizers, adequate soil moisture management, and maintaining good ventilation in closed cultivation systems.

• Marginal leaf necrosis
• Chlorosis and tissue bleaching
• Root system damage and decay
• Sudden wilting or stunted growth