Zeolite amendment enhances grain yield and mitigates greenhouse gas emissions in an intensive aerobic rice system

Intensive aerobic rice system (I_IARS) can enhance water use efficiency and mitigate methane (CH₄) emissions, but it may decrease rice grain yields and stimulate nitrous oxide (N₂O) emissions by incurring a water deficit. Therefore, eco-efficient strategies are required to maintain rice grain yields while reducing the environmental burden associated with I_IARS. Zeolite is a promising soil conditioner for increasing rice yields and mitigating greenhouse gas emissions. However, how zeolite amendment affects rice grain yield and CH₄ and N₂O emissions in I_IARS remains elusive. In this study, a two-year field experiment was conducted to elucidate the impacts of zeolite amendment on the rice grain yield, irrigation input, water use efficiency, CH₄ and N₂O emissions, global warming potential (GWP), and associated soil parameters, including redox potential (Eh), pH, NH₄⁺, and NO₃⁻ under continuously flooded irrigation (I_CF) and I_IARS. We found that I_IARS significantly mitigated CH₄ emissions by 65–80 % but increased N₂O emissions by 35–239 % relative to I_CF. Notably, zeolite amendment mitigated CH₄ and N₂O emissions by 8–45 % and 13–22 % under I_IARS, respectively, relative to the non-zeolite control. Accordingly, zeolite amendment significantly decreased the GWP by 10–38 % under I_IARS compared with the non-zeolite control. Concurrently, I_IARS significantly increased the rice grain yield by 15 % in 2022 but obtained an equivalent yield in 2023 compared with I_CF, and zeolite amendment resulted in significant increases in rice grain yields of 7 % and 8 % in 2022 and 2023, respectively, relative to the non-zeolite control. The lower GWP and higher rice grain yield observed under zeolite-amendment treatment can be attributed to the reduced soil NH₄⁺ and increased NO₃⁻ concentrations. Consequently, soil amendment with zeolite in I_IARS paddy fields is an optimal strategy regarding environmental sustainability and safeguarding food security.