A Previous investigation by the writer (1) showed that cyanamide readily breaks down, yielding ammonia in normal clay and sandy soils. The evidence, however, threw no light upon the cause or nature of this change. This question was accordingly reserved for a later investigation. The concensus of the available evidence indicated that the production of ammonia from cyanamide in the soil is due to direct bacterial action. This view was held by Immendorff(2) and Kappen(3), who concluded that in poor soils of low bacterial activities cyanamide is not converted into ammonia but is chemically transformed into dicyanodiamide. Löhnis(4) at first accounted in a similar way for the formation of ammonia from cyanamide in the soil. He(5) assumed later, however, that cyanamide is normally decomposed by soil colloids into urea or possibly some other substances, and the latter are then converted into ammonia by the soil organisms. He adduced no direct evidence of the production of urea from cyanamide in the soil.