Zeolite mitigates N2O emissions in paddy fields under alternate wetting and drying irrigation

Increasing studies indicate that alternate wetting and drying irrigation (I-AWD) can significantly increase water use efficiency in paddy fields, whereas this method may also cause high nitrous oxide (N2O) emissions. Therefore, effective management strategies are urgently required for ameliorating the adverse effect of I-AWD on N2O emissions. Zeolite is increasingly used as a potential effective soil conditioner to reduce N2O emissions. However, few studies have been conducted to explore the effect of zeolite on N2O emissions and rice grain yield as well as the associated soil physicochemical properties in paddy fields under I-AWD. Here, a two-year field experiment was conducted using lysimeters to assess the effect of two irrigation regimes (I-CF: continuously flooded irrigation; I-AWD: alternate wetting and drying irrigation) and two zeolite management regimes (Z(U): urea alone (non-zeolite control); Z(UZ): urea combined with zeolite (15 t ha(-1))) on N2O emissions, rice grain yield, and soil physicochemical properties. The results showed that I(AWD )significantly increased N2O emissions by 18% relative to I-CF, and Z(UZ) significantly reduced N2O emissions under I-AWD by 9% compared to Z(U). I-AWD had no significant effect on rice grain yield compared to I-CF. However, Z(UZ) significantly enhanced rice grain yield under I-CF and I-AWD by 11% and 14%, respectively, compared to Z(U). Accordingly, Z(UZ )significantly decreased yield-scaled N2O emissions under I-CF and I-AWD by 13% and 19%, respectively, compared to Z(U). Increases in soil NH4+-N concentrations and soil pH contribute to the N2O mitigation in Z(UZ) under I-AWD. Altogether, our results highlight that zeolite combined with urea is likely a sustainable resource-efficient approach for mitigating N2O emissions while increasing rice grain yield in paddy fields under I-AWD.

Automated summary

Studies have shown that alternate wetting and drying irrigation (I-AWD) can improve water use efficiency in paddy fields, but also increase nitrous oxide (N2O) emissions. This study found that using zeolite as a soil conditioner can effectively reduce N2O emissions and increase rice grain yield under I-AWD. The combination of zeolite and urea is a sustainable approach for mitigating N2O emissions and improving rice grain yield in paddy fields.