Higher nicotine concentration in upper leaves is one of main reasons that cause lower usability of tobacco leaves in Chinese present tobacco production. In 2002, Two field experiments were conducted at Fenggang and Jinsha of Guizhou province in order to understand the effects of nitrogen supply on tobacco production, dry matter, nitrogen accumulation in plant, the change of mineral nitrogen and nitrate concentration in petiole of the first spreading leave, and to study mineralization of soil nitr...