State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, 430072, China.
Department of Environmental Sciences, University of California, Riverside, CA, 92521, USA.
Environ Sci Pollut Res Int. 2018 May;25(15):14511-14520. doi: 10.1007/s11356-018-1666-2. Epub 2018 Mar 10.
Anaerobic batch experiments were conducted to study the regulatory role of endogenous iron in greenhouse gas emissions under intensive nitrogen fertilization in subtropical soils of China. Fe, Fe, and NO-N dynamics and NO, CH, and CO emissions, as well as the relationships between N fertilizer, endogenous iron, and greenhouse gas emissions were investigated. The emissions of NO increased to different extents from all the test soils by N1 (260 mg N kg) application compared with N0. After 24 days of anaerobic incubation, the cumulative emissions of NO from red soils in De'an (DR) were significantly higher than that from paddy soils in De'an (DP) and Qujialing (QP) under N1. However, N application enhanced CH and CO emissions from the red soils slightly but inhibited the emissions from paddy soils. The maximal CH and CO emission fluxes occurred in DP soil without N input. Pearson's correlation analysis showed that there were significant correlations (P < 0.01) between Fe and Fe, NO-N, (NO + N)-N concentrations in DP soil, implying that Fe oxidation was coupled with nitrate reduction accompanied by (NO + N)-N emissions and the endogenous iron played a regulatory role in greenhouse gas emissions mainly through the involvement in denitrification. The proportion of the electrons donated by Fe used for NO production in denitrification in DP soil was approximately 37.53%. Moreover, positive correlations between Fe and CH, CO were found in both DR and QP soils, suggesting that endogenous iron might regulate the anaerobic decomposition of organic carbon to CH and CO in the two soils. Soil pH was also an important factor controlling greenhouse gas emissions by affecting endogenous iron availability and C and N transformation processes.
采用静态厌氧批实验研究了中国亚热带土壤在集约化施氮条件下，内源性铁对温室气体排放的调控作用。研究了 Fe、Fe 和 NO-N 动态变化、NO、CH 和 CO 排放以及氮肥、内源性铁与温室气体排放之间的关系。与 N0 相比，N1（260mg N kg）处理下，所有测试土壤的 NO 排放均有不同程度的增加。在厌氧培养 24 天后，与德安（DR）稻田土壤相比，德安（DR）红壤和曲家岭（QP）红壤的 NO 累积排放量在 N1 下显著增加。然而，氮的施加略微增加了红壤中 CH 和 CO 的排放，但抑制了稻田土壤中 CH 和 CO 的排放。最大的 CH 和 CO 排放通量出现在没有氮输入的 DP 土壤中。Pearson 相关分析表明，DP 土壤中 Fe 与 Fe、NO-N、（NO + N）-N 浓度之间存在显著相关性（P<0.01），表明 Fe 氧化与硝酸盐还原耦合，伴随着（NO + N）-N 的排放，内源性铁在温室气体排放中起调控作用，主要是通过参与反硝化作用。DP 土壤中，Fe 用于反硝化过程中生成 NO 的电子占比约为 37.53%。此外，在 DR 和 QP 土壤中均发现 Fe 与 CH、CO 之间存在正相关关系，表明内源性铁可能调节这两种土壤中有机碳的厌氧分解生成 CH 和 CO。土壤 pH 也是通过影响内源性铁的可用性和 C、N 转化过程来控制温室气体排放的重要因素。
