What is a primary disadvantage of using chelates for micronutrient supply?

Using chelates for micronutrient supply carries a primary disadvantage in that they are generally the most expensive form of micronutrient fertilizers. Chelated micronutrients are complexed with organic molecules, which enhances their availability to plants and helps to improve their stability in the soil. However, this process and the materials involved increase the cost compared to other forms of micronutrients, such as inorganic salts or unchelated forms.

The higher expense can be a significant factor for farmers and land managers, especially when considering large-scale applications or tight budgets. While chelates provide benefits in specific scenarios — such as preventing micronutrient deficiencies in crops — the cost factor must be weighed against their advantages in nutrient management systems.

The other choices, while they may contain some truth in different contexts, do not highlight the primary disadvantage accurately. For instance, chelates are typically not the least soluble option; they are designed for increased availability, which often means higher solubility compared to other forms. Therefore, understanding the economic implications is crucial for effective nutrient management strategies.