Question

Deep black soil is considered to be highly productive due to high proportion of

• A. Silt and earthworm
• B. Clay and humus
• C. Gravel and Ca${}^{2+}$
• D. Sand and Zn${}^{2+}$

Answer 1

The correct option is B Clay and humus

Black soil is dark brown or black colour soil. The black colour is due to organic matter and clay content. Such soils are compact with good hydration, but little aeration; chemically they are very fertile, because of rich mineral content. Rich mineral content of black soils is due to clay, which adsorbs minerals on its surface. Clay and humus produce colloidal complex for holding water and ions and forming soil crumbs.