Effects of 2-chloro-6-(trichloromethyl)-pyridine on the nitrification of ammonium sulphate and its recovery by rye-grass

Ammonium sulphate alone and treated with the nitrification inhibitor 2-chloro-6-(trichloromethyl)- pyridine, at rates equivalent to 1 and 2% of the weight of N applied, was applied to sandy- and clay-loam soils. Ammonium sulphate was given in November 1962, and soil samples, taken in spring 1963, down to 36 in. on the sandy-loam and 18 in. on the clay-loam, were analysed. When the ammonium sulphate was broadcast on the soil surface, 2% of the inhibitor, inhibited nitrification of the ammonium-N more than 1%, but when it was placed in the soil both rates were equally effective.