• Compost has the advantage that it improves soil structure and aeration; increases the soil?s water-holding capacity; and stimulates healthy root development (Twarog, 2006).

• They determined that about 27.5% and 5.9% of C in maize root and straw, respectively, is retained as SOM annually after mineralization.

• Bioactive ligands called Myc factors and Nod factors secreted by mycorrhiza and Rhizobium were perceived by host roots to trigger the signal transduction pathway [106,107], which initiates further signal transduction pathway through unknown receptors (SYMRK and NORK) [101] which trigger release of Ca2+ in the cytosol [108].