What is a soil test?

A soil test is a comprehensive process involving the collection of soil samples and subsequent laboratory analysis to determine various characteristics of the soil, particularly nutrient levels and pH. This information is crucial for understanding the soil's fertility and its suitability for different crops or plants. By analyzing the nutrient levels, farmers and gardeners can make informed decisions about fertilization and soil management practices that can enhance plant growth and productivity.

In contrast to other options, soil testing is a structured method that provides quantitative data essential for agricultural planning and environmental management. For instance, assessing soil temperature, while useful for certain agronomic decisions, does not provide the depth of information regarding nutrient availability and soil health that a lab analysis does. Similarly, an informal evaluation of soil texture, though helpful in understanding basic soil properties, lacks the precision and detail obtained through a formal soil test. Estimating soil organic matter can contribute to understanding soil quality, but it is only one aspect of what a full soil test encompasses. Hence, the extensive analysis included in option B makes it the most accurate definition of a soil test.