What limitation is described by the soil subclass 'M'?

The soil subclass designated by 'M' refers specifically to moisture limitations that affect agricultural crops, particularly due to drought conditions. This classification highlights the challenges posed by insufficient moisture, which can significantly hinder crop growth and agricultural productivity. Practicing in regions characterized by this subclass requires an understanding of water management practices and drought-resistant crops to mitigate the impact of these limitations on farming efforts.

In contrast, the other subclasses address different soil challenges such as salinity, flooding, or drainage issues, which are not the primary concern indicated by the 'M' subclass. Each of these classes outlines a distinct soil condition that complicates land use but does not encompass the moisture limitation aspects that the 'M' subclass signifies.