Abstract:

【Objective】The objective of the study was to determine the influences of four different kinds of nitrification inhibitors, DMPP, DCD, AM and TU, on soil nitrite accumulation, and to select the best nitrification inhibitor for nitrogen fertilizer in calcareous soil.【Method】The contents of ammonium nitrogen, nitrite nitrogen, nitrate nitrogen and pH were measured, and apparent nitrification rate and inhibitory rate of different nitrification inhibitors were calculated.【Result】The results showed that under the experimental conditions (60% of water hold capacity, 25℃), little nitrite nitrogen was found in the soil treated with nitrification inhibitors DMPP, DCD, and AM, however; while some nitrite nitrogen was found in the TU treatment in the beginning eight days. The nitrification inhibition rate was in the order of 10%DCD＞1%DMPP＞5%AM (depending on the amount of applied pure N). DMPP, DCD and AM treatments induced nitrification process lag behind 35-39 d.【Conclusion】DMPP, DCD and AM could significantly inhibit the accumulation of nitrite nitrogen in calcareous soil. The inhibitory effects of DMPP, DCD and AM were evident, while that of TU was not.

Key words: nitrification inhibitor, nitrite, nitrification inhibitor rate, DMPP, DCD