The effect of a nitrification inhibitor on the concentration of nitrate in grass during growth

Summary In an experiment on clay-loam soil ammonium sulphate with or without the nitrification inhibitor 2-chloro-6-(trichloromethyl) pyridine (at 2% of the weight of N in fertilizer) or sodium nitrate were applied at 100 or 200 lb N/acre to the seedbed before sowing S22 Italian ryegrass and again after the first cut. Eighty-four days after the first dressing, all the grass given 100 lb N/acre contained similar amounts of nitrate-N; with 200 lb N/acre, grass given ammonium sulphate alone contained most nitrate-N and grass given ammonium sulphate plus inhibitor least. Forty-two days after the second dressing, all the grass given 100 lb N/acre again contained similar amounts of nitrate-N and with 200 lb N/acre, grass given sodium nitrate contained most nitrate-N and that given ammonium sulphate plus inhibitor least.