[Effects of different nitrogen regulators on nitrogen transformation in different soil types]

Area of Science:

• Agricultural Science
• Soil Science
• Environmental Science

Background:

• Nitrification is a key soil process influencing nitrogen availability and loss.
• Dicyandiamide (DCD) and 3,5-dimethylpyrazole (DMP) are known nitrification inhibitors.
• North China Plain soils, including meadow-cinnamon and fluvo-aquic types, are crucial for agriculture.

Purpose of the Study:

• To compare the nitrification inhibitory effects of DCD and DMP in two major North China Plain soils.
• To investigate the synergistic effect of DMP combined with the urease inhibitor hydroquinone (HQ) on nitrogen transformation.

Main Methods:

• Laboratory incubation experiments were conducted.
• Meadow-cinnamon soil and fluvo-aquic soil were used as test matrices.
• Treatments included DCD, DMP, DMP + HQ, and a control without inhibitors.

Main Results:

• DMP demonstrated a stronger nitrification inhibitory effect than DCD in both soil types.
• DMP application significantly increased soil ammonium-nitrogen (NH4+-N) by 149.5%-387.2% and decreased nitrate-nitrogen (NO3--N) by 22.3%-55.3%.
• Inhibitory effects were more pronounced in fluvo-aquic soil compared to meadow-cinnamon soil. DMP and HQ exhibited a significant synergistic effect on nitrogen transformation.

Conclusions:

• DMP is a more effective nitrification inhibitor than DCD for the studied North China Plain soils.
• Combining DMP with HQ enhances nitrogen transformation regulation, offering potential for improved nitrogen use efficiency in agriculture.