The effectiveness and persistence of a nitrification inhibitor, 2-chloro-6-(trichloromethyl) pyridine, in soils

Abstract

A greenhouse experiment was conducted to determine the effect of 2-chloro-6-(trichloromethyl) pyridine, nitrapyrin, on nitrification in a Norwood silty clay loam under two moisture regimes. Calcium nitrate and ammonium sulfate were applied at the rate of 400 kg N/ha in a band. Ammonium sulfate was applied alone and with 0.5 and 1.0% nitrapyrin. Oats, Avena sativa L., and sudangrass, Sorghum vulgare sudanense (Piper) Hitchc,. Were grown for yield and analyzed for protein and nitrate content. Effluent water samples were collected and analyzed for nitrate content. Nitrapyrin decreased nitrification which in turn decreased the amount of nitrate leached through the 40 cm columns. The addition of nitrapyrin also decreased the nitrate percentage in the plant tissue. Yield and protein content was not significantly different, but nitrogen use efficiency was greater for the ammonium treatments than for the nitrate treatment. A field experiment was conducted with corn, Zea mays L., using 75 and 150 kg N/ha as ammonium sulfate applied as a side-dress in a band without and with 1.0% nitrapyrin. Nitrapyrin did not significantly decrease nitrification in the soil or increase yield. An extraction procedure for nitrapyrin and 6-chloropicolinic acid (6-CPA) was developed in which has chromatographic analysis was used. Efficiency of extraction from three different soils is discussed for nitrapyrin and 6-CPA. A laboratory experiment was conducted to determine the movement of ammonium, nitrate, and nitrapyrin in soil columns leached with varying amounts of distilled water..