DENDROLOGY

Detailed explanation-1: -Thus, clay has the highest humus content. Humus is the organic component of soil, formed by the decomposition of leaves and other plant material by soil microorganisms.

Detailed explanation-2: -Loam is actually a soil mixture with a high clay content, and humus is organic matter present in soil (particularly in the top organic “O” layer), but neither are a main type of soil.

Detailed explanation-3: -’A’ horizon is the topmost layer of soil profile. The maximum content of humus is found in this layer. The humus content decreases as we move deeper. This is because most of the living organisms live in the topmost layer of soil i.e. ‘A’ horizon.