Objective The aim was to explore the impact of applying silicon fertilizer on the emission of nitrous oxide (N2O), and to clarify the mechanism of the effect of applying silicon fertilizer on N2O emissions under different land use conditions, in order to provide a theoretical basis for controlling N₂O emissions.

Method A two-factor completely randomized incubation experiment was conducted, comprising six treatments: three land-use types (grassland (G), broadleaf forest (F), and bamboo forest (B)) and two silicon fertilizer levels (no silicon application (S0) and silicon application (S1)). On the days of 0, 1, 3, 7, 15, and 30 of the incubation, the soil N₂O emission rates, ammonium nitrogen and nitrate nitrogen contents, and the activities of three enzymes (nitrate reductase, nitrite reductase, and urease) were measured.

Result Regardless of land-use type, silicon fertilizer application significantly reduced the soil N₂O emission rate. The total N₂O emissions from grassland, broadleaf forest and bamboo forest soils were reduced by 11.6%, 16.03% and 11.9%, respectively. Silicon fertilizer application also significantly decreased the soil ammonium nitrogen and nitrate nitrogen contents and the activities of the three enzymes (nitrate reductase, nitrite reductase, and urease). Correlation analysis indicated that the soil N₂O emission rate was significantly correlated with soil ammonium nitrogen content, nitrate nitrogen content, and nitrite reductase activities.

Conclusion The effect of silicon fertilizer application on soil N₂O emissions was consistent in direction across the different land-use types, indicating that silicon fertilizer has broad applicability in reducing N₂O emissions from forest and grassland soils.