Which class indicates soils that cannot be improved for agricultural use?

Class 6 soils are classified as those that have significant limitations that make them unsuitable for agricultural use, and these limitations are such that they cannot be reasonably improved. This class typically includes soils with severe erosion, very poor drainage, or particular characteristics that restrict their capacity to sustain crops or other agricultural activities.

In contrast, other classes, such as Class 4 and Class 5, are considered to have limitations but can still be improved to some extent for agricultural use. Class 0 is not a standard classification within soil capability categories and may refer to a non-existent or specific context that does not apply universally.

Therefore, recognizing the characteristics of Class 6 is crucial, as it defines soils that are fundamentally impeded against agricultural improvement.