ABSTRACT
Rock powders are sources of essentially all the biological elements except (in general) for nitrogen, while biochar is less a fertilizer per se since it largely consists of elemental carbon. However, biochar acts physically and chemically as a sponge that absorbs and retains nutrients and water, making them available to plant roots via interaction with symbiotic fungi and bacteria (Ladygina and Rineau, 2013). So biochar and rock powders should be highly complementary, especially when combined with nitrogenrich composts.
