Soil Judging National Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

The loamy mollic horizon needs to have a thickness within a specific range to accurately conduct the argillic/cambic test. This test is critical as it helps in identifying soil characteristics that determine its classification and potential use.

The correct range of thickness, which is between 18-25 cm, provides sufficient depth for the mollic horizon to exhibit its properties effectively, including its moisture retention and nutrient-holding capacities. This specific thickness ensures that the horizon is well-developed and indicative of significant soil processes such as organic matter accumulation and clay illuviation, which are essential for interpreting the soil's profile.

A horizon thickness less than 18 cm may not provide a reliable representation of the mollic horizon's properties, while a thickness greater than 25 cm could indicate that the soil has been exposed to other factors that may alter its classification or characteristics. A fixed measurement at 20 cm does not account for the natural variability found in soils, making the range of 18-25 cm more appropriate for conducting this particular test.