Dr. Mariani Sembiring, Sp., Mp is a lecturer at the faculty of agriculture University of North Sumatra, Indonesia. Completing his doctoral college at North Sumatera university. The subjects taught are the foundations of soil science, soil ecology, soil biotechnology, soil biology, microbial fertilizer and soil fertility. Has more than 50 papers published in national and international journals and publications at national and international seminars. Academic position at north sumatera university is as head of ground biology labolatorium.