氮输入对闽江口芦苇湿地土壤有效态硅组成及含量的影响
- Effects of exogenous nitrogen input on Valid Silicon composition and content in soils of Phragmites australis marsh in the Min River estuary , ChinaWANG Yidan1,2,3,ZHAI Shuijing1,2,3,*,YU Xinhui4,WANG Wenjing1,2,3
- 基金项目：福建省自然科学(2023J01517)；国家自然科学基金面上项目(No. 42371105)
- 王一丹
- 福建师范大学福建省亚热带资源与环境重点实验室
- 翟水晶
- 福建师范大学福建省亚热带资源与环境重点实验室
- 王文静
- 福建师范大学福建省亚热带资源与环境重点实验室
- 摘要：河口湿地是重要的氮汇区，对湿地土壤其他元素的循环过程有重要的影响。研究外源氮输入对河口湿地土壤有效态硅组成及含量的影响，对于明确氮负荷增强对河口湿地硅的生物地球化学循环过程有着重要的意义。基于此，本研究于2021年3月-2022年4月以闽江河口鳝鱼滩芦苇湿地为研究对象，模拟不同氮输入条件（CK：对照处理，LN：低氮输入，MN：中氮输入，HN：高氮输入）对湿地土壤有效态硅的影响。结果表明：有效态硅各组分含量由高到低依次为铁锰氧化物结合态硅、有机质-硫化物结合态硅、碳酸盐结合态硅、可交换态硅，氮输入并未改变其排序；在CK条件下土壤中可交换态硅、碳酸盐结合态硅、铁锰氧化物结合态硅、有机质-硫化物结合态硅的含量均值分别为104.88mg·kg-1、177.49mg·kg-1、9728.30mg·kg-1、3158.03mg·kg-1。可交换态硅含量在LN、MN、HN输入条件下分别升高了7.10%、6.22%、13.01%，而碳酸盐结合态硅含量分别降低了11.46%、11.30%、12.71%，铁锰氧化物结合态硅含量分别上升了3.94%、5.09%、6.00%，有机质-硫化物结合态硅含量在LN、MN输入下分别降低了0.27%、6.12%，而在HN输入下增加了1.67%。据分析，这可能是由于氮输入改变了土壤pH、EC等理化性质，从而使土壤中部分碳酸盐结合态硅和有机质-硫化物结合态硅转化为可交换态硅，同时促进了铁锰氧化物结合态硅的积累。由此可见，氮输入可将土壤中潜在生物可利用的硅转换为生物可直接利用的硅，这对研究硅在湿地土壤的生物地球化学循环过程提供新的思路，为揭示湿地生态系统元素耦合关系研究提供理论依据。
- Abstract：Estuarine wetlands are important nitrogen sinks, which have important effects on the cycling processes of other elements in wetland soils. The study of the effects of exogenous N inputs on the composition and content of valid silicon (Si) in estuarine wetland soils is of great significance in clarifying the biogeochemical cycling processes of Si in estuarine wetlands due to enhanced N loading. Based on this, a field simulation experiment was carried out in Phragmites australis marsh soils of the Shanyutan wetland in the Min River estuary from March 2021 to April 2022. We set up four different nitrogen input treatments as follows: no nitrogen input (CK), low nitrogen input (LN), medium nitrogen input (MN) and high nitrogen input (HN).The objective of the experiment was to study the effect of nitrogen deposition on the content and composition of the valid silicon. The results showed that the content of each component of valid Si from high to low was respectively Si bound to Iron-Manganese Oxide (IMOF-Si), Si bound to Organic sulfide (OSF-Si), Si bound to Carbonate (CF-Si) and Exchangeable Si (IEF-Si), which was consistent with CK. The average contents of IEF-Si, CF-Si, IMOF-Si and OSF-Si in the CK condition were 104.88 mg·kg-1, 177.49 mg·kg-1, 9728.30 mg·kg-1, and 3158.03 mg·kg-1, respectively. Under the input of LN, MN and HN, compared with CK, the content of IEF-Si increased by 7.10%, 6.22% and 13.01% and the content of IMOF-Si increased by 3.94%, 5.09% and 6.00%, respectively. However, the content of CF-Si decreased by 11.46%, 11.30% and 12.71% respectively. For OSF-Si, the content decreased by 0.27% in LN input and 6.12% in MN input, whereas increased by 1.67% in HN input. Meanwhile, we found that the exogenous nitrogen altered the Electrical Conductivity(EC) and pH of wetland soils in the Min River estuary, which maybe converted part of CF-Si and OSF-Si to IEF-Si, and also promoted the accumulation of IMOF-Si in the soil. It followed that nitrogen input could contribute to the conversion of potential bioavailable Si in the soil into direct bioavailable Si for plants. This could provide a new idea to study the biogeochemical cycling process of silicon in wetland soils and provide a theoretical basis to elucidate the elemental coupling relationships in wetland ecosystems.
