Agronomy Degree Practice Exam

How is the quality of an agricultural lime material measured?

1. Guaranteed analysis

2. County extension office

3. Cation exchange capacity

4. Effective calcium carbonate equivalent

The correct answer is: Effective calcium carbonate equivalent

The quality of agricultural lime material is measured by its Effective Calcium Carbonate Equivalent (ECCE). This metric provides a standardized way to evaluate the liming ability of different agricultural limes based on their content of calcium and magnesium carbonates as well as other components that influence soil pH. A higher ECCE indicates a more effective liming material, meaning it will raise soil pH more effectively when applied, which is crucial for promoting healthy crop growth. In comparison, guaranteed analysis typically refers to the statement of the actual content of nutrients in fertilizers, making it less applicable for assessing lime quality. The county extension office serves as a resource for information and guidance, but it does not directly measure lime quality. Cation exchange capacity is a soil property that indicates the soil's ability to hold cations and is not specifically a measure of lime quality itself. Effective Calcium Carbonate Equivalent thus emerges as the most relevant and accurate measure for evaluating the quality of agricultural lime materials.