铁铝氧化物添加对亚热带森林土壤碳氮矿化的影响
Effects of Fe and Al Oxides Additions on Carbon and Nitrogen Mineralization in Subtropical Forest Soil
焦明睿 1郭琦玲 1马红亮1
作者信息
- 1. 福建师范大学地理研究所,福州 350117;福建师范大学湿润亚热带生态地理过程教育部重点实验室,福州 350117
- 折叠
摘要
铁铝氧化物是土壤中常见的化学物质,参与土壤氧化还原反应,然而不同含量的铁铝氧化物对森林土壤碳氮转化的影响尚不明晰.为探究铁铝氧化物含量对土壤碳氮矿化的影响及差异,选择亚热带森林土壤为研究对象,将不同含量的铁铝氧化物(分析纯Fe(OH)3:0,10,20,30,50,70 g·kg-1,分析纯Al(OH)3:0,1,2,3,5,7 g·kg-1)分别与 50g(以干质量计)土壤样品混匀,进行室内恒温好氧培养,分析温室气体排放速率及累积排放量、DOC(可溶性有机碳)、无机氮和氮转化速率变化.结果显示:1)铁氧化物添加后,土壤DOC含量降低,50 和70g·kg-1处理的DOC含量分别显著降低了 29.86%和 33.90%,CO2 和CH4 累积排放量与添加量均呈显著正相关,而CH4 与CO2 累积排放量呈显著正相关、与DOC含量呈负相关.随铁氧化物添加量增加,土壤净硝化作用更加显著,当添加量为 10g·kg-1时,净硝化速率为5.58 mg·kg-1·d-1;而当添加量为70g·kg-1时,净硝化速率可达到43.31 mg·kg-1·d-1.DON(可溶性有机氮)含量表现出先升后降的趋势,低量(0～20 g·kg-1)处理随添加量增加从25.62 mg·kg-1增长到61.60 mg·kg-1,高量(30～70 g·kg-1)处理则随添加量增加从62.01 mg·kg-1降低到12.74 mg·kg-1.因此,20～30 g·kg-1铁氧化物有可能是影响土壤中有机氮分解和矿化的分界点.2)铝氧化物添加对土壤碳矿化促进效果较弱,甚至抑制CO2 排放,对土壤CH4 排放、DOC含量和净氮矿化均无明显影响,但DON含量显著增加了92.47%～173.69%.本研究未发现铁铝氧化物对N2O排放的影响.综上,铁氧化物可促进土壤碳氮矿化,而铝氧化物作用相对较弱或有抑制效果.
Abstract
Fe and Al oxides are common chemical substances in soil,which participate in soil redox reactions,but their roles of different contents in carbon and nitrogen transformation in forest soil are still not well understood.In order to explore the effects and different roles of Fe and Al oxide content on soil carbon and nitrogen mineralization,subtropical forest soil was selected as the research object.Different amounts of Fe and Al oxide(Fe(OH)3:0,10,20,30,50,70 g·kg-1 and Al(OH)3:0,1,2,3,5,7 g·kg-1)were mixed with 50 g(based on dry mass)soil samples,and the indoor aerobic incubation was carried out at constant temperature.Greenhouse gas emission rate and cumulative emissions,DOC(dissolved organic carbon),inorganic nitrogen and nitrogen transformation rate were analyzed.The results showed that:1)after Fe oxide addition,soil DOC content decreased with the added levels,and the DOC content of 50 and 70 g·kg-1 treatment signifi-cantly decreased by 29.86%and 33.90%,respectively.The cumulative emissions of CO2 and CH4 were significantly positively correlated with Fe oxides added levels.And CH4 cumulative emissions was positively correlated with CO2 cumulative emissions but negatively correlated with DOC content.The increase of Fe oxide addition significantly promoted the soil net nitrification.When the addition amount was 10 g·kg-1,the net nitrification rate was 5.58 mg·kg-1·d-1,but the net nitrification rate reached 43.31 mg·kg-1·d-1 at 70 g·kg-1.The DON(dissolved organic nitrogen)content in-creased from 25.62 mg·kg-1 to 61.60 mg·kg-1 at a range of 0～20 g·kg-1,and then decreased from 62.01 mg·kg-1 to 12.74 mg·kg-1 at 30～70 g·kg-1.So,20～30 g·kg-1 Fe oxide may be the critical value affecting the decomposition and mineralization of organic nitrogen in soil.2)The addition of Al oxide had a weak effect on promoting soil carbon mineralization,and even inhibited CO2 emission.Al oxide addition did not significantly affect soil CH4 emission,DOC content and net nitro-gen mineralization,but DON content increased significantly by 92.47%～173.69%.In this study,the effects of Fe and Al oxides on N2O emissions were not found.In summary,Fe oxide can promote soil carbon and nitrogen mineralization,while Al oxides have relatively weak or inhibiting effects.
关键词
亚热带森林土壤/铁铝氧化物/土壤碳氮矿化/温室气体Key words
subtropical forest soil/Fe and Al oxides/soil carbon and nitrogen mineralization/greenhouse gas引用本文复制引用
基金项目
福建省属公益类科研院所基本科研专项(2023R1038)
国家自然科学基金项目(31770659)
大学生创新训练计划项目(cxxl-2021382)
出版年
2024
NETL
NSTL
万方数据