Inhibition of nitrification in soils by volatile sulfur compounds

Carbon disulfide, dimethyl disulfide, methyl mercaptan, dimethyl sulfide, and hydrogen sulfide retard nitrification of ammonium in soils incubated in closed systems. The inhibitory effects of these volatile sulfur compounds on nitrification decrease in the order listed. Hydrogen sulfide is a relatively weak inhibitor of nitrification, but carbon disulfide is considerably more effective than patented nitrification inhibitors (N-Serve. AM, and ST) for inhibition of nitrification in closed systems.It is concluded from the work reported that the inhibitory effects of methionine, cystine, cysteine, and other nonvolatile organic sulfur compounds on nitrification in soils may be at least partly due to decomposition of these compounds by soil microorganisms with formation of volatile sulfur compounds that retard nitrification.