In agricultural production, rational fertilization is key to improving crop yield and quality. As one of the three major nutrient elements, nitrogen is crucial for citrus growth. not all nitrogen application methods are suitable for the development of citrus. The following are several nitrogen fertilization practices that are unsuitable for citrus:

1. Excessive Application of Urea (N)

   • Urea is the main component of nitrogen fertilizers. Excessive use can lead to overly high nitrogen content in the soil, causing nitrogen toxicity.
   • Symptoms of nitrogen toxicity include stunted plant growth, yellowing leaves, poor root development, and severe cases may even result in plant death.
   • To avoid nitrogen toxicity, it is necessary to apply nitrogen fertilizers reasonably based on soil test results and crop requirements. Generally, slow-release or controlled-release nitrogen fertilizers are recommended.

2. Applying Nitrogen Directly to the Soil Surface (0-30 cm)

   • Applying nitrogen fertilizer directly to the surface layer of soil may reduce its mobility, making it difficult for roots to absorb.
   • Additionally, the surface soil tends to have higher temperatures, accelerating nitrogen decomposition and leading to nutrient loss.
   • To improve nitrogen utilization, it is advisable to apply fertilizers deeper (30-60 cm). This reduces nitrogen volatilization and leaching while promoting root growth downward for better nutrient absorption.

3. Uneven Fertilization

   • Uneven distribution of fertilizers leads to imbalanced nutrient allocation between plants and different parts of the same plant, affecting normal growth.
   • It may also cause deficiencies in some areas while excessive application in others.
   • For healthy citrus growth, adopt balanced fertilization methods to ensure all parts receive adequate nutrients.

4. Sole Application of Nitrogen Fertilizer

   • While nitrogen is essential for plant growth, relying solely on nitrogen fertilizer cannot meet all nutritional needs of citrus.
   • Citrus also requires significant amounts of phosphorus, potassium, and other elements, which are critical for growth, fruit quality, and disease resistance.
   • sole nitrogen application is insufficient. A comprehensive approach with multiple nutrients tailored to crop demands is necessary.

5. Excessive Use of High-Nitrogen Compound Fertilizers

   • Overapplying compound fertilizers with high nitrogen content can lead to soil acidification, lowering soil pH.
   • Acidified soil impairs citrus root respiration, weakening root function and reducing the plant’s ability to absorb nutrients and grow.
   • Excessive use of such fertilizers may also disrupt the balance of other soil nutrients, further harming crop development.

citrus cultivation should avoid practices such as excessive urea application, surface fertilization (0-30 cm), uneven distribution, sole nitrogen use, and overreliance on high-nitrogen compound fertilizers. To enhance yield and fruit quality, adopt scientific fertilization methods that maintain balanced soil nutrients.