Abstract: The present invention relates to increasing and/or maintaining nitrogen content in soil by administration of granular or powdered nitrification inhibitors coated with urease inhibitors. In one embodiment, urease inhibitors are dispersed in an improved organo liquid delivery system at concentration levels of 50-90%. In another embodiment, urease inhibitors were applied in a non-aqueous, organo liquid delivery system coating solid nitrification inhibitors utilizing simple blending equipment at temperatures of 20°-70° C. Another embodiment discloses a dry, flowable additive containing a nitrification inhibitor coated with a urease inhibitor which can be administered directly to the soil, to a dry natural and/or a manmade fertilizer or to a liquid fertilizer which provides for the reduction of nitrogen loss from the soil.