College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China.
Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, 610041, China.
Environ Sci Pollut Res Int. 2018 May;25(13):13014-13025. doi: 10.1007/s11356-018-1559-4. Epub 2018 Feb 26.
In recent years, rice paddies have been increasingly converted to vegetable production resulting from economic benefits and changes in demand of diets, potentially altering soil greenhouse gas (GHG) balance. Here, we implemented a parallel field experiment to simultaneously quantify the differences in emissions of CH and NO among rice paddy (RP) and conventional vegetable field (CV) and greenhouse vegetable field (GV), both of which have been recently converted from rice paddy in subtropical China over a full year. The results revealed that CH emission was reduced dramatically by nearly 100% following the initial land management change from rice to vegetable production, with annual emissions of 720.9, 0.9, and 0.2 kg CH-C ha for RP, CV, and GV, respectively. This conversion however substantially increased NO emissions, resulting in the transition from a minor sink of NO in RP (-0.1 kg N ha yr) to considerable NO sources in CV (31.8 kg N ha yr) and GV (52.2 kg N ha yr). Furthermore, annual NO emission from GV significantly exceeded that from CV due to lower soil pH and higher soil temperature facilitating NO production in GV relative to CV. Land management change significantly decreased the annual total emissions of CH and NO from CV and GV by 19-51% as compared to RP, attributing to the reduced CH emissions outweighing the increased NO emissions in CV and GV. These results indicate that expansion of vegetable production at the expense of rice paddies for higher economic benefits also helps mitigate the total emissions of CH and NO.
近年来，由于经济效益和饮食需求的变化，稻田越来越多地被改造成蔬菜生产地，这可能改变了土壤温室气体（GHG）平衡。在这里，我们实施了一个平行的田间实验，同时量化了水稻田（RP）和常规菜地（CV）以及温室菜地（GV）之间 CH 和 NO 排放的差异，这两个菜地都是在过去一年中从中国亚热带地区的稻田转换而来的。结果表明，初始土地管理从水稻改为蔬菜生产后，CH 排放急剧减少近 100%，RP、CV 和 GV 的年排放量分别为 720.9、0.9 和 0.2 kg CH-C ha。然而，这种转换大大增加了 NO 的排放，导致从 RP（-0.1 kg N ha yr）中较小的 NO 汇转变为 CV（31.8 kg N ha yr）和 GV（52.2 kg N ha yr）中的大量 NO 源。此外，由于土壤 pH 值较低和土壤温度较高，有利于 GV 中 NO 的产生，与 CV 相比，GV 的年 NO 排放量显著高于 CV。与 RP 相比，CV 和 GV 的土地管理变化使 CH 和 NO 的年总排放量分别减少了 19-51%，这归因于 CV 和 GV 中减少的 CH 排放量超过了增加的 NO 排放量。这些结果表明，为了更高的经济效益而扩大蔬菜生产，以牺牲稻田为代价，也有助于减少 CH 和 NO 的总排放量。
