Fertilizer burn

Fertilizer burn (Nutrient toxicity) is a physiological disorder characterized by damage to plant tissues caused by an excessive concentration of mineral salts. This condition occurs due to improper application of fertilizers, leading to osmotic stress where the roots are unable to absorb water, and in severe cases, water is drawn out of the plant cells, resulting in wilting and necrosis.

This disorder can affect a wide variety of plants, including ornamental species, vegetables, and field crops. Corn (maize) is particularly susceptible to fertilizer burn when nitrogen fertilizers are applied too close to the seeds during planting or at excessively high rates, causing a localized salt accumulation that inhibits root elongation and seedling emergence.

Typical symptoms manifest as necrotic tissue along the leaf margins, yellowing or browning of foliage, and a scorched appearance. The root system may show stunted growth, browned or blackened tips, and a lack of secondary roots. In acute cases, the entire plant may collapse rapidly as if it were suffering from severe drought.

The severity of fertilizer burn is heavily influenced by environmental factors such as high soil temperatures, low humidity, and insufficient moisture levels. When the soil is dry, the concentration of salts in the soil solution increases, drastically raising the osmotic pressure and making it impossible for the plant to take up necessary nutrients.

The economic impact of fertilizer toxicity can be significant, ranging from reduced growth rates and harvest yields to the total loss of a crop. Prevention strategies include strictly adhering to recommended fertilizer application rates, ensuring proper soil moisture, opting for slow-release fertilizers, and keeping granular products from coming into direct contact with seeds or sensitive root zones.