Context

Integrated rice–aquatic animals culture systems (RACSs) are of interest in sustainability research because they have been found to host diverse species and there is potential for positive synergistic effects between the plant (rice) and aquatic animal culture. However, their effect on soil fertility, rice productivity, and greenhouse gas (GHG) emissions, as well as the associations among them, remain unclear.

Objectives

A meta-analysis was conducted to systematically evaluate the sustainability of RACSs from the perspective of “rice productivity–GHG emissions–soil fertility” and their associations and to clarify how environmental factors and fertilizer-management practices affect responses of rice yield and GHG emissions to RACSs.

Methods

We conducted a meta-analysis of 1807 paired observations collected from 78 published papers covering four countries that compared soil fertility, rice yield, and GHG emissions in a conventional rice monoculture system (CRMS) and in a RACS.

Results

Overall, the RACSs improved soil structure (soil bulk density declined by 5.8 % and total and capillary porosity increased by 6.4 % and 5.7 %, respectively), increased soil organic carbon (C, 7.9 %) and nitrogen (N, 6.6 %) storage, and reduced CH₄ (9.2 %) and N₂O (4.5 %) emissions; rice yield were little higher (by 2.0 %) than that of the CRMS. However, the effects varied under different RACS modes, environmental factors, and fertilizer-management practices. For instance, compared to CRMS, yields were 4.1 % higher in the rice–duck mode, 3.9 % lower in the rice–crayfish mode, and the no significantly change in the rice–fish system. The effects on GHG emissions and soil fertility were more pronounced in the rice–duck and rice–crayfish modes than in the rice–fish mode. Furthermore, paddy soils with low fertility (lower soil organic C and N) and less nutrient (nitrogen and phosphorus) input provide a higher rice yield and lower GHG emissions under RACSs.

Conclusions

Overall, the RACSs stabilized rice productivity and reduced GHG emissions by improving the soil structure and increasing soil C and N sequestration; however, the effects varied by different RACS modes, initial soil properties, fertilizer input rate, and climate conditions. As such, environmental factors and nutrient management should be considered when designing and deciding what type of RACSs to employ. Our results also highlight the great potential of RACSs in the development of sustainable agriculture practices in the context of climate change.

Implications

Future research and applications should consider the response of RACSs to climate and environmental factors and fertilizer-management practices, to achieve greater production and environmental benefits.

中文翻译：

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水稻-水产综合养殖系统通过提高土壤肥力和减少温室气体排放促进农业可持续发展

语境

稻米-水生动物综合养殖系统 (RACS) 在可持续性研究中很受关注，因为它们被发现可以容纳多种物种，并且植物（稻米）和水生动物养殖之间有可能产生积极的协同效应。然而，它们对土壤肥力、水稻生产力和温室气体 (GHG) 排放的影响以及它们之间的关联仍不清楚。

目标

进行了荟萃分析，从“水稻生产力-温室气体排放-土壤肥力”及其关联的角度系统评估 RACS 的可持续性，并阐明环境因素和肥料管理实践如何影响水稻产量和温室气体排放对水稻产量和温室气体排放的响应RACS。

方法

我们对从涵盖四个国家的 78 篇已发表论文中收集的 1807 对观察结果进行了荟萃分析，这些论文比较了传统水稻单一栽培系统 (CRMS) 和 RACS 中的土壤肥力、水稻产量和温室气体排放量。

结果

总体而言，RACS 改善了土壤结构（土壤容重下降了 5.8%，总孔隙率和毛细管孔隙率分别增加了 6.4% 和 5.7%），增加了土壤有机碳（C，7.9%）和氮（N，6.6%）的储存量, 并减少 CH ₄ (9.2 %) 和 N ₂O（4.5%）排放；水稻产量略高于 CRMS（高 2.0%）。然而，在不同的 RACS 模式、环境因素和肥料管理实践下，效果各不相同。例如，与CRMS相比，稻鸭模式的产量提高了4.1%，稻小龙虾模式的产量降低了3.9%，而稻鱼系统没有显着变化。稻-鸭和稻-小龙虾模式对温室气体排放和土壤肥力的影响比稻-鱼模式更显着。此外，低肥力（较低的土壤有机碳和氮）和较少养分（氮和磷）输入的水稻土在 RACSs 下提供更高的水稻产量和更低的温室气体排放。

结论

总的来说，RACSs 通过改善土壤结构和增加土壤碳和氮固存来稳定水稻生产力并减少温室气体排放；然而，影响因不同的 RACS 模式、初始土壤特性、肥料输入率和气候条件而异。因此，在设计和决定采用何种类型的 RACS 时，应考虑环境因素和养分管理。我们的结果还强调了 RACS 在气候变化背景下发展可持续农业实践的巨大潜力。

启示

未来的研究和应用应考虑 RACS 对气候和环境因素以及肥料管理实践的响应，以实现更大的生产和环境效益。