Hou Yu, Zhang Jingwen, Guo Junjie, Zhou Wang, Qin Ziqi, Zhu Qingsong, He Qinxia
Guangdong Key Laboratory of Marine Civil Engineering, School of Civil Engineering, Sun Yat-sen University, Zhuhai, Guangdong, China.
State Key Laboratory of Efficient Utilization of Agricultural Water Resources, China Agricultural University, Beijing, China.
Glob Chang Biol. 2025 Jun;31(6):e70283. doi: 10.1111/gcb.70283.
Rice feeds more than 50% of the global population with significant greenhouse gas (GHG) emissions. Non-continuous flooding (NCF) has been recognized as an effective practice for stabilizing rice yields, conserving water, and reducing GHG emissions from rice fields. However, the impacts of NCF on net carbon sequestration (NCS, defined as the total ecosystem GHG equivalent) in rice fields, including CH emissions, NO emissions, photosynthetic carbon sequestration linked to crop yield, and soil organic carbon (SOC) sequestration, have rarely been quantified comprehensively. This limitation hinders a complete understanding of the overall processes through which NCF affects NCS. This study conducted a meta-analysis of 1075 data pairs from 72 studies worldwide to quantify the effects of NCF on GHG equivalent components and its overall NCS benefits. Results showed that compared to continuous flooding (CF), NCF significantly increased the average NCS per growing season by 4615 kg CO-eq·ha (95% CIs: 468 to 8761, p = 0.031). Specifically, NCF significantly reduced CH emissions by 45.72% and significantly increased NO emissions by 35.77%, with an insignificant increase of 1.93% and 3.16% in CO emissions and yield, respectively. The ΔSOC (changes of SOC concentration before and after the growing season) significantly decreased with the mean difference effect size of -0.36 (95% CIs: -0.70 to -0.02), indicating smaller SOC changes for NCF. Meta-regression and random forest importance analyses were used to explore the effects of climatic and soil properties and management practices on GHG equivalent components. Implementing controlled irrigation with appropriate limitation of total water input could achieve a win-win situation of enhancing rice yield while mitigating GWP and Y-GWP. This study further quantified the effects of NCF on all components of GHG equivalent and the NCS benefits in rice fields, providing guidance for irrigation management practices to achieve dual carbon goals.
水稻养活了全球超过50%的人口，同时排放大量温室气体（GHG）。非连续淹灌（NCF）已被认为是稳定水稻产量、节约用水和减少稻田温室气体排放的有效措施。然而，NCF对稻田净碳固存（NCS，定义为生态系统温室气体当量总量）的影响，包括CH排放、NO排放、与作物产量相关的光合碳固存以及土壤有机碳（SOC）固存，很少得到全面量化。这一限制阻碍了对NCF影响NCS的整体过程的全面理解。本研究对来自全球72项研究的1075个数据对进行了荟萃分析，以量化NCF对温室气体当量成分及其整体NCS效益的影响。结果表明，与连续淹灌（CF）相比，NCF显著提高了每个生长季的平均NCS，增加了4615 kg CO2-eq·ha（95%置信区间：468至8761，p = 0.031）。具体而言，NCF显著减少了45.72%的CH排放，显著增加了35.77%的NO排放，CO排放和产量分别有不显著的增加，增幅为1.93%和3.16%。ΔSOC（生长季前后SOC浓度的变化）显著下降，平均差异效应大小为-0.36（95%置信区间：-0.70至-0.02），表明NCF的SOC变化较小。采用荟萃回归和随机森林重要性分析来探讨气候、土壤性质和管理措施对温室气体当量成分的影响。实施控制灌溉并适当限制总水投入可以实现提高水稻产量同时减轻全球变暖潜势（GWP）和产量-全球变暖潜势（Y-GWP）的双赢局面。本研究进一步量化了NCF对稻田温室气体当量所有成分的影响以及NCS效益，为灌溉管理措施实现双碳目标提供了指导。
