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  土壤学报  2018, Vol. 55 Issue (5): 1041-1050  DOI: 10.11766/trxb201802260035
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引用本文  

王璐莹, 秦雷, 吕宪国, 等. 铁促进土壤有机碳累积作用研究进展. 土壤学报, 2018, 55(5): 1041-1050.
WANG Luying, QIN Lei, LÜ Xianguo, et al. Progress in Researches on Effect of Iron Promoting Accumulation of Soil Organic Carbon. Acta Pedologica Sinica, 2018, 55(5): 1041-1050.

基金项目

国家重点研发专项(2016YFC0500408)资助

通讯作者Corresponding author

邹元春, E-mail: zouyc@iga.ac.cn

作者简介

王璐莹(1994—),女,辽宁人,硕士研究生,主要从事生物地球化学循环研究。E-mail: wangluying@iga.ac.cn
铁促进土壤有机碳累积作用研究进展
王璐莹1,2 , 秦雷1 , 吕宪国1 , 姜明1 , 邹元春1     
1. 中国科学院东北地理与农业生态研究所湿地生态与环境重点实验室,长白山湿地与生态吉林省联合重点实验室,长春 130102;
2. 中国科学院大学,北京 100049
摘要:土壤中总有机碳的含量可反映土壤的有机质含量进而反映土壤肥力水平。在众多的有机碳累积的影响因子中,铁在土壤有机碳的累积方面发挥着“捕获”有机碳并形成“锈汇”的重要作用。本文总结了前人的研究成果,得出土壤中有机碳的固持机制主要包括团聚体的物理保护、矿物质的化学保护、微生物的生物保护以及有机碳自身的保护,并以前两者为主,且铁紧密地参与到物理、化学和生物保护机制中的结论。这说明铁在土壤有机碳累积过程中起重要作用。铁通过促进团聚体的形成、与有机碳发生共沉淀和吸附作用以及影响微生物活性的方式分别参与到物理、化学和生物保护机制中。有机碳自身的保护作用主要体现在一部分有机碳的抗分解性。建议今后更多地关注氧化还原性质活跃的、生态服务功能显著的土壤系统的有机碳固持及碳汇功能恢复机制,更加注重不同机制的定量化研究及重要性对比研究,加强模拟实验研究,更好地实现理论服务于实践。
关键词土壤有机碳    铁氧化物    团聚体    共沉淀    吸附    微生物    

土壤有机碳的总量可以反映土壤有机质的总量,土壤有机质的总量又可以表征土壤肥力[1]。据调查,我国土壤碳密度在世界上处于较低水平,尤其以表层土壤有机碳密度最为显著[2]。表明我国生态系统的总体质量较低。即使如此,土壤仍是陆地生态系统中的最大的有机碳库,在全球的碳循环过程中发挥着非常重要的作用[3]。在积极应对全球气候变化的过程中,通过土壤固碳来减少温室气体的排放是主要手段之一。我国土壤有机碳密度低,因此具有较大的固碳减排的空间。由此可见,探究土壤有机碳的稳定机制不仅可以提高土壤肥力,还是应对全球气候变化的重要举措。目前公认的土壤有机碳的稳定机制有四种:物理保护、化学保护、生物保护和土壤有机碳的自身的抗分解性[4]。在有机碳稳定过程中,铁作为在土壤中含量高且氧化还原性质活跃的金属元素,起到了重要的作用。但是目前关于铁在土壤有机碳累积的不同机制中的作用的研究较少。本文将对四种土壤有机碳的稳定机制的作用过程分别做以阐述,并剖析铁在每种机制中所起到的作用,以期阐明铁在促进土壤有机碳累积过程中的重要性,促进铁的生物地球化学循环研究。此外,本文将根据已有研究提出建议,以期为今后的科研工作起到指向性作用。

1 铁在土壤中的赋存形态

铁在地壳内的数量仅次于氧、硅和铝,位居第4,在地壳中含量丰富且氧化还原性质活跃[5]。土壤中的铁几乎以氧化铁的形态存在,成土过程中母质风化的产物经过再积淀是土壤中氧化铁的主要成因,矿物中的铁在风化作用下游离在硅酸盐外,成为了氧化铁。观察结果表明,凡是有氧化铝存在的土壤中均含有氧化铁,但反之,含有氧化铁的土壤中却不一定含有氧化铝。由此可知,氧化铁广泛分布于各类土壤中[6]。土壤中常见的氧化铁为赤铁矿、磁赤铁矿、针铁矿、纤铁矿、水铁矿和氢氧化铁凝胶[6-7]。土壤中氧化铁的主要存在形态包括:游离态氧化铁(Fed)、无定型态氧化铁(Feo)和络合态氧化铁(Fep)[8]。游离态氧化铁指土壤中排除在层状硅酸盐组成部分之外的铁,主要是土壤黏粒中的铁氧化物和水化合物[7, 9],也可定义为可以用连二亚硫酸钠-柠檬酸钠-重碳酸钠(DCB)法提取的氧化铁[6]。土壤中或土壤粘粒中的游离态铁氧化物在全铁(FeT)中所占的百分数即为铁的游离度(100×Fed/FeT),对反映土壤风化程度具有重要意义[6, 10-11]。土壤中的无定形铁指能用草酸铵提取的氧化铁,是游离态氧化铁中的一部分,活性较高,比表面积较大,不发生X射线衍射的水合氧化铁[10, 12-13]。无定形铁在游离态铁中所占的百分比叫做氧化铁的活化度(100×Feo/Fed),可判定土壤的发生特征和土类,反映某些成土环境对土壤发生的影响[10, 13],(1-100×Feo/Fed)表示氧化铁的老化程度[7]。游离氧化铁与无定形氧化铁(Feo)的差值为晶质氧化铁[10]。络合态铁(Fep)能够与土壤腐殖质形成络合物,即能被焦磷酸钠提取的那部分氧化铁[6],属于无定形物质,但是由于不能完全被草酸铵缓冲液提取,因此,并不完全包含于无定形铁中[14]。络合态铁占游离态铁的百分比为铁的络合度(100×Fep/Fed)[15],土壤络合铁的含量和络合度与有机质含量正相关,是铁离子在土壤中迁移转化的主要原因之一[10]

2 土壤中有机碳的累积机制 2.1 团聚体的物理保护作用

按粒径大小分组可将土壤有机碳分成颗粒有机碳(POC)和矿质结合态有机碳(MOC,<53μm),其中,颗粒有机碳又可分为粗颗粒有机碳(cPOC,>250μm)和细颗粒有机碳(fPOC,53~250μm)[16-17]。其中,>250μm的为大团聚体,<250μm的为微团聚体[18],两者又可细分为粗大团聚体、细大团聚体、微团聚体粉和粉-黏团聚体[19]。70%以上的SOC存在于<53μm的微团聚体中[20]。但一般土壤大团聚体中土壤有机碳(SOC)浓度较微团聚体高[21-22],这是因为微团聚体被有机质胶结成了大团聚体[23],大团聚体中正在分解的植物根系和各类菌丝也会提高其SOC浓度。一部分有机碳主要被包裹于土壤团聚体颗粒内,这种作用主要存在于粗颗粒(cPOC,>250μm)和细颗粒(fPOC,53~250μm)中。很多学者对团聚体对土壤有机碳的物理保护作用进行了研究,土壤中约有90%的有机碳储存在团聚体中,故将其认为是土壤有机碳累积的重要的机制之一。团聚体对土壤有机碳的物理保护机制较为复杂,受到团聚体的密度、孔隙度、持水量、粒级大小、抗拉强度、土壤类型、土层深度等多种因素的影响,且二者之间相互作用、相互制约,但是团聚体对有机碳的物理保护作用存在饱和点[21, 24-29]

2.2 矿物质的化学保护作用

土壤团聚体可以通过物理保护和化学保护两种作用来促进有机碳的累积。通过化学作用被保护的这部分有机碳被吸附于土壤团聚体颗粒表面,主要存在于矿物结合态中(MOC,<53μm),这一过程中黏土矿物和金属氧化物起到主要作用,氢键、离子交换、晶体结构、比表面积等均会影响黏土矿物对有机质的吸附,与有机碳形成有机-无机复合体[4, 24, 30-31]。矿物结合态有机碳的化学稳定性较高,是惰性有机碳,土壤中细矿物颗粒对有机碳的吸附作用被认为是土壤固持有机碳的重要机制之一[24, 32-36]

2.3 微生物的生物保护作用

描述土壤微生物活性的指标包括:土壤微生物生物量碳、微生物菌系总量、功能菌系总量、铁还原菌总量[37]。在自然状态下,湿地土壤碳循环的过程大致是:湿地植物通过光合作用吸收大气中的CO2和H2O转化成有机物储存在植物体内并释放出氧气,植物残体或根系残体会在土壤中沉积形成有机质,土壤微生物的分解作用可将有机质分解并释放CO2和CH4到大气中。研究表明,土壤有机碳每年通过微生物分解作用向大气中释放的碳是68~100 Pg,约占大气中CO2储量的10%[38-39]。在气候和水文条件的影响下,微生物的活性和酶活性会受到影响,蔗糖酶会促进有机质分解,促进微生物生长繁殖,同时,微生物又会刺激酶的活性增强。总体而言,土壤的微生物活性与水分含量正相关,在土壤水分丧失的情况下,微生物的活性受到抑制,植物残体的分解速率降低,有机质得到累积[40-43]

2.4 有机碳的自身保护作用

有机碳自身的保护作用主要来源于有机碳的难降解性。土壤的有机碳中,碳水化合物、蛋白质类物质等易降解,且多分布于表层土壤中。而深层土壤中的有机碳来源、化学组成等均不同于表层土壤,多为芳香类多聚物、木质素、多酚、真菌和放线菌的合成产物等均难以降解的物质,这部分有机碳具有较强的抗分解性,对土壤中有机碳的累积起到重要作用[4, 44-45]

通过对前人的研究进行总结,将上述的四种土壤有机碳稳定机制进行了对比分析,结果如表 1所示。

表 1 土壤有机碳的稳定机制 Table 1 Stability mechanism of soil organic carbon
3 铁促进土壤有机碳稳定的方式 3.1 铁促进土壤团聚体的形成

土壤团聚体是经过一系列物理、化学、生物作用形成的,主要依靠土壤中的有机、无机胶结物质以及有机无机复合体。铁铝氧化物表面活性高,是重要的无机胶结物[47-49]。铁铝氧化物对团聚体形成的促进作用主要表现在有机质含量不高、但铁铝氧化物含量较高的酸性土壤中,三价铁和三价铝氧化物对土壤团聚体的形成和稳定起着重要作用[47, 50]。与氧化铝相比,铁氧化物更广泛地存在于各类土壤中,因此,铁氧化物对团聚体形成的作用更为普遍。铁氧化物稳定团聚体主要是依靠在溶液中充当絮凝剂、在黏粒和有机分子之间充当胶结剂和充当凝胶沉淀在粘粒表面[51-52]。铁氧化物的结晶度会对团聚体产生影响,低结晶的铁氧化物较结晶度高的铁氧化物对有机碳的稳定作用更强[53]。且不同形态的铁氧化物对团聚体的影响程度不同,团聚体的稳定性与游离态铁的含量正相关,通过络合作用与有机碳形成化学稳定性有机碳,增强土壤团聚体的张力强度,提高团聚的稳定性[50, 54-55]。羟基可作为金属离子配位体与其他配位体进行交换,并在土壤中充当絮凝剂来促进大团聚体的形成,而无定型铁正是氧化铁中活性羟基的主要贡献者,此外,相比于游离态铁,无定型铁氧化物还具有更大的表面积和更高的表面活性,具有更强的胶结能力[56-58]。络合态铁氧化物为铁氧化物与有机质的胶结产物,其自身的属性决定了其对大团聚体形成的促进作用[58]。因此,与游离态铁相比,无定形态和络合态铁氧化物对大团聚体的形成和稳定的作用更大[58]

3.2 铁与土壤中溶解性有机碳发生共沉淀

土壤中铁氧化物不仅可以作为胶结剂参与形成土壤团聚体颗粒,从而形成对有机碳的物理隔离保护[15, 59],还可以与可溶性有机碳发生共沉淀[60-62]。共沉淀的本质跟3.1部分内容是相同的,结果都是形成闭蓄态有机质从而降低有机碳的生物有效性、提高有机碳的稳定性以促进有机碳在土壤中的累积。研究表明,土壤中有机碳对Fe3+有巨大的亲和力,但是对Fe2+没有[63]。因此,与有机碳发生共沉淀的为三价铁氧化物[63]。土壤中的Fe2+在一般土壤中很快会被氧化为Fe3+,然后发生水解反应形成铁氧化物,这些铁氧化物如果是在有机碳存在的情况下同时形成的,就会发生共沉淀[64-65]。铁氧化物与有机碳的共沉淀作用可以固持的OC:Fe可达6~10[61],具有较高的有机碳固持容量。有机碳分子与铁离子的共沉淀不是一次完成的,而是随着铁、碳周期性的扩散聚集,形成了一层一层类似洋葱的结构[46-66],这种模式下,OC:Fe比可达10,有利于减缓微生物对有机碳的分解[67]。一旦处于厌氧环境中,铁还原导致闭蓄态结构被破坏,原本包裹在结构体内部的有机碳得以释放,这部分有机碳由于与铁氧化物之间的结合较为松散而将被优先降解,“洋葱”结构逐渐解体,OC:Fe比率逐渐降低[46]。与铝氧化物相比之下,吸附在铁矿物表面的有机碳较难降解,可以继续维持有机碳的相对稳定性[60]。Nierop等[68]发现80%以上的溶解性有机碳(DOC)与Fe3+发生共沉淀,大分子DOC优先被沉淀出来,而小分子DOC将继续存在于土壤溶液中,等待与新输入的铁离子发生吸附作用或共沉淀作用。

3.3 铁吸附土壤中可溶性有机碳

铁氧化物对可溶性有机碳的吸附作用的产生是由于:木质素纤维对铁铝氧化物的氧化分解作用需要在金属表面和酸性有机配体尤其是那些与芳香族有关的配体之间形成强络合键[60],主要包括配位体交换和阳离子架桥两种吸附机制[69],吸附力的强度受表面面积、土壤pH、氧化物形态及含量等多种复杂因素的影响[31, 69-71]。在淀积层土壤中,铁氧化物是最重要的吸附剂,而淋溶层土壤中硅酸盐的贡献较大。土壤比表面积并不能很好地表征有机碳稳定潜势,短期碳周转受到有机碳内在的抗分解性和外部颗粒物的控制,而长期效应则受到铁矿物表面吸附的控制[72-73]。在对泥炭地的研究中,水铁矿吸附有机大分子的能力高于纤铁矿和针铁矿,但在海洋环境中,以针铁矿对有机碳的吸附作用为主[74]。研究表明,铁氧化物对溶解态有机碳的吸附作用存在饱和点,有机碳的吸附量随着初始较小的C:Fe比率线性增加,然后在达到一个较大的C:Fe比率时逐渐接近最大值,研究表明,由于饱和吸附量的存在,铁氧化物能固持的最大C:Fe比为1.0[61-64]

3.4 铁对土壤中微生物的影响

微生物在铁碳循环过程中具有一定的驱动作用,其驱动的铁碳循环过程有两种方式:一种是生活在厌氧环境中的光能自养铁氧化菌为了满足自身的生存需要,利用固定CO2合成生物量,这一过程中,Fe2+是唯一的电子供体[75-77];另一种是在铁还原菌与产甲烷菌同时存在的厌氧环境中,两者由于竞争还原Fe3+而抑制甲烷的产生,从而使有机碳得到累积[76, 78-79]。而在微生物驱动的铁碳循环过程中,铁是细菌的潜在能量来源,Fe2+和Fe3+可分别作为无机营养细菌的电子受体和厌氧铁呼吸的末端电子受体[80]。铁可以通过影响团聚体、有机质等来间接影响微生物的活性和微生物量[39, 81-83]。Fe2+可为微生物提供营养,Fe3+对微生物存在抑制作用,Fe0可为微生物提供电子受体和营养物质[79]。过量的铁可以通过影响微生物的活性间接影响土壤有机碳的固持[85]。一项在水稻田中进行外源输入Fe2+的研究也显示,当Fe2+含量超过土壤微生物的耐受范围时,会产生铁毒胁迫,导致土壤微生物活性降低,并抑制水稻的生长[37]

上述铁促进土壤有机碳稳定方式的对比见表 2

表 2 铁在土壤有机碳稳定方式中的作用 Table 2 Roles of iron in soil organic carbon stabilization
4 展望

尽管近三十年来有机碳固持已经得到国内外众多研究者的关注,但仍然存在很大的可继续探究的空间。针对已有研究,未来关于铁对土壤有机碳累积作用的研究应着眼于以下几个方面。

1) 之前国内关于铁对土壤有机碳累积作用的研究多集中在森林、草地、农田等土地类型和中国南方土壤中,主要目的是提高土壤肥力增加农作物产量等,对于北方土壤比如对有地球之肾之称的湿地土壤的研究比较欠缺,故今后的研究要更多地面向生态保护和恢复的研究。更为重要的是,在铁促进有机碳累积的机制中,氧化还原过程是重要的机制之一,因此,更应加强氧化还原活跃的土壤系统中铁促进有机碳累积的作用与机制的研究,以及对氧化还原活跃土壤系统中的机制与已有的主要针对好氧土壤系统中的机制的差异的研究。

2) 目前已有的铁对土壤有机碳的固持机理的研究,多为定性描述和简单的相关分析,国外近五年内有关于铁氧化物对有机碳的共沉淀和吸附解吸作用的研究,但是国内有机碳固持机理的定量描述、不同土壤中不同稳定机理的相对重要性评估等研究缺乏,故建议加强对机理的定量研究,并能阐明不同机理在有机碳保护中的相对重要性。

3) 目前国内外对于微生物对有机碳累积的作用研究还不够深入,关于铁在促进微生物稳定有机碳过程中的作用的研究还处在推理阶段,没有明确的结论及相应的数据支撑,在今后的研究中更多地关注微生物驱动的铁碳耦合机制以探究铁如何通过影响微生物来间接影响有机碳的累积是很有必要的。

4) 目前此类研究多集中在室内分析实验,而对已有理论的应用性研究相对欠缺,往往很多理论经不住实践的检验,或是所得结论不具有代表性,因此对理论的应用也就成了科学研究中的薄弱环节。建议在以后的研究中将室内试验与模拟培养试验相结合,以探究已有的有机碳固持机理的实用性,尽量做到理论服务于实践。

参考文献
[1]
谢驾阳.地表覆盖和施氮对西北旱地土壤有机碳氮及供氮能力的影响.陕西杨凌: 西北农林科技大学, 2009
Xie J Y. Effect of surface mulching and nitrogen application on soil nitrogen supply capacity and organic C and N on north-west dryland (In Chinese). Yangling, Shaanxi: Northwest Agriculture and Forestry University, 2009 http://cdmd.cnki.com.cn/Article/CDMD-10712-2010051136.htm (0)
[2]
潘根兴. 中国土壤有机碳库及其演变与应对气候变化. 气候变化研究进展, 2008, 4(5): 282-289.
Pan G X. Soil organic carbon stock, dynamics and climate change mitigation of China (In Chinese). Advances in Climate Change Research, 2008, 4(5): 282-289. DOI:10.3969/j.issn.1673-1719.2008.05.006 (0)
[3]
周莉, 李保国, 周广胜. 土壤有机碳的主导影响因子及其研究进展. 地球科学进展, 2005, 20(1): 99-105.
Zhou L, Li B G, Zhou G S. Advances in controlling factors of soil organic carbon (In Chinese). Advances in Earth Science, 2005, 20(1): 99-105. DOI:10.3321/j.issn:1001-8166.2005.01.016 (0)
[4]
刘满强, 胡锋, 陈小云. 土壤有机碳稳定机制研究进展. 生态学报, 2007, 27(6): 2642-2650.
Liu M Q, Hu F, Chen X Y. A review on mechanisms of soil organic carbon stabilization (In Chinese). Acta Ecological Sinica, 2007, 27(6): 2642-2650. DOI:10.3321/j.issn:1000-0933.2007.06.059 (0)
[5]
何念祖. 植物的铁营养. 土壤学进展, 1986(1): 21-25.
He N Z. The iron nutrition of plants (In Chinese). Progress in Soil Science, 1986(1): 21-25. (0)
[6]
于天仁, 王振权. 土壤分析化学. 北京: 科学出版社, 1988.
Yu T R, Wang Z Q. Soil analytical chemistry (In Chinese). Beijing: Science Press, 1988. (0)
[7]
陈家坊, 何群, 邵宗臣. 土壤中氧化铁的活化过程的探讨. 土壤学报, 1983, 20(4): 387-393.
Chen J F, He Q, Shao Z C. Study on the activation process of iron oxides in soil (In Chinese). Acta Pedologica Sinica, 1983, 20(4): 387-393. (0)
[8]
张元一, 张元福. 几种土壤中不同形态铁及无定形硅铝的比较研究. 黑龙江八一农垦大学学报, 1989(1): 19-24.
Zhang Y Y, Zhang Y F. Compared study on different morphological iron and amorphous silica and alumium in the various soils (In Chinese). Journal of Heilongjiang August First Land Reclamation University, 1989(1): 19-24. (0)
[9]
陈家坊. 土壤胶体中的氧化物. 土壤通报, 1981, 18(2): 44-49.
Chen J F. The oxide in the soil colloid (In Chinese). Chinese Journal of Soil Science, 1981, 18(2): 44-49. (0)
[10]
何群, 陈家坊. 土壤中游离铁和络合态铁的测定. 土壤, 1983, 15(6): 242-244.
He Q, Chen J F. Determination of free iron and complex iron in soil (In Chinese). Soils, 1983, 15(6): 242-244. (0)
[11]
邹元春, 吕宪国, 姜明. 不同开垦年限湿地土壤铁变化特征研究. 环境科学, 2008, 29(3): 814-818.
Zou Y C, Lü X G, Jiang M. Characteristics of the wetland soil iron under different ages of reclamation (In Chinese). Environmental Science, 2008, 29(3): 814-818. DOI:10.3321/j.issn:0250-3301.2008.03.046 (0)
[12]
迟光宇, 张兆伟, 陈欣, 等. 羟胺浸提-可见分光光度法测定土壤无定形铁. 光谱学与光谱分析, 2008, 28(12): 2931-2934.
Chi G Y, Zhang Z W, Chen X, et al. Determination of amorphous iron oxides in soil by hydroxylamine extraction-spectrophotometry (In Chinese). Spectroscopy and Spectral Analysis, 2008, 28(12): 2931-2934. DOI:10.3964/j.issn.1000-0593(2008)12-2931-04 (0)
[13]
许祖诒, 陈家坊. 土壤中无定形氧化铁的测定. 土壤通报, 1980, 11(6): 32-34.
Xu Z Y, Chen J F. Determination of amorphous iron oxide in soil (In Chinese). Chinese Journal of Soil Science, 1980, 11(6): 32-34. (0)
[14]
何群, 陈家坊, 许祖诒. 土壤中氧化铁的转化及其对土壤结构的影响. 土壤学报, 1981, 18(4): 326-334.
He Q, Chen J F, Xu Z Y. Influence of transdormation of iron oxides on soil structure (In Chinese). Acta Pedologica Sinica, 1981, 18(4): 326-334. (0)
[15]
熊毅. 土壤胶体. 第一册. 北京: 科学出版社, 1983.
Hseung Y. Soil colloids (In Chinese). 1 st vol. Beijing: Science Press, 1983. (0)
[16]
李林森, 程淑兰, 方华军, 等. 氮素富集对青藏高原高寒草甸土壤有机碳迁移和累积过程的影响. 土壤学报, 2015, 52(1): 183-193.
Li L S, Cheng S L, Fang H J, et al. Effect of nitrogen enrichment on transfer and accumulation of soil organic carbon in alpine meadows on the Qinghai-Tibetan Plateau (In Chinese). Acta Pedologica Sinica, 2015, 52(1): 183-193. (0)
[17]
刘中良, 宇万太. 土壤团聚体中有机碳研究进展. 中国生态农业学报, 2011, 19(2): 447-455.
Liu Z L, Yu W T. Review of researches on soil aggregate and soil organic carbon (In Chinese). Chinese Journal of Eco-Agriculture, 2011, 19(2): 447-455. (0)
[18]
Tisdall J M, Oades J M. Organic matter and water-stable aggregates in soils . European Journal of Soil Science, 1982, 33(2): 141-163. (0)
[19]
Cambardella C A, Elliott E T. Carbon and nitrogen dynamics of soil organic matter fractions from cultivated grassland soils . Soil Science Society of America Journal, 1994, 58(1): 123-130. DOI:10.2136/sssaj1994.03615995005800010017x (0)
[20]
窦森, 王其存, 代晓燕. 土壤有机培肥对微团聚体组成及其碳, 氮分布和活性的影响. 吉林农业大学学报, 1991, 13(2): 43-48.
Dou S, Wang Q C, Dai X Y. Effect of improving soil fertility by organic materials on the composition, C, N distribution and activity of microaggregates (In Chinese). Journal of Jilin Agricultural University, 1991, 13(2): 43-48. (0)
[21]
Jastrow J, Miller R. Soil aggregate stabilization and carbon sequestration: Feedbacks through organomineral associations//Lal R, Kimble J M, Follett R F, et al. Soil processes and the carbon cycle. Boca Raton, Fla: CRC Press, 1998: 207-223 (0)
[22]
Six J, Elliott E T, Paustian K. Soil macroaggregate turnover and microaggregate formation:Amechanism for C sequestration under no-tillage agriculture . Soil Biology & Biochemistry, 2000, 32(14): 2099-2103. (0)
[23]
Elliott E T. Aggregate structure and carbon, nitrogen, and phosphorus in native and cultivated soils . Soil Science Society of America Journal, 1986, 50(3): 627-633. DOI:10.2136/sssaj1986.03615995005000030017x (0)
[24]
Six J, Conant R T, Paul E A, et al. Stabilization mechanisms of soil organic matter:Implications for c-saturation of soils . Plant and Soil, 2002, 241(2): 155-176. DOI:10.1023/A:1016125726789 (0)
[25]
Six J, Paustian K, Elliott E T, et al. Soil structure and organic matter:Ⅰ. Distribution of aggregate-size classes and aggregate-associated carbon . Soil Science Society of America Journal, 2000, 64(2): 681-689. DOI:10.2136/sssaj2000.642681x (0)
[26]
娄鑫.温带森林次生演替中土壤团聚体及其有机碳保护机制研究-以长白山为例.北京: 中国科学院大学, 2013
Lou X. Effect of succession stages on stability of water stable aggregate and the protect of SOM in Temperate Forest-A case study in Changbai Mountain (In Chinese). Beijing: Univertsity of Chinese Academy of Sciences, 2013 http://www.wanfangdata.com.cn/details/detail.do?_type=degree&id=Y2369570 (0)
[27]
潘根兴, 周萍, 李恋卿, 等. 固碳土壤学的核心科学问题与研究进展. 土壤学报, 2007, 44(2): 327-337.
Pan G X, Zhou P, Li L Q, et al. Core issues and research progresses of soil science of C sequestration (In Chinese). Acta Pedologica Sinica, 2007, 44(2): 327-337. DOI:10.3321/j.issn:0564-3929.2007.02.020 (0)
[28]
周萍, 宋国菡, 潘根兴, 等. 南方三种典型水稻土长期试验下有机碳积累机制研究Ⅰ.团聚体物理保护作用. 土壤学报, 2008, 45(6): 1063-1071.
Zhou P, Song G H, Pan G X, et al. SOC accumulation in three najor types of paddy soils sunder long-term agro-ecosystem exper ments from south ChinaⅠ. Physical prorection in soil micro-aggregates (In Chinese). Acta Pedologica Sinica, 2008, 45(6): 1063-1071. DOI:10.3321/j.issn:0564-3929.2008.06.008 (0)
[29]
张延, 梁爱珍, 张晓平, 等. 土壤团聚体对有机碳物理保护机制研究. 土壤与作物, 2015, 4(2): 85-90.
Zhang Y, Liang A Z, Zhang X P, et al. Progress in soil aggregates physical conservation mechanism for organic carbon (In Chinese). Soil and Crop, 2015, 4(2): 85-90. (0)
[30]
Lützow M V, Kögel-Knabner I, Ekschmitt K, et al. Stabilization of organic matter in temperate soils:Mechanisms and their relevance under different soil conditions -A review . European Journal of Soil Science, 2006, 57(4): 426-445. DOI:10.1111/ejs.2006.57.issue-4 (0)
[31]
宋华萍.赤红壤区粘土矿物对土壤有机质的固存与转化机理的研究.南宁: 广西大学, 2015
Song H P. Latosolic red soil area of clay minerial of the sequestration and transformation machanism of soil organic matter (In Chinese). Nanning: Ghuangxi University, 2015 http://www.wanfangdata.com.cn/details/detail.do?_type=degree&id=Y2887646 (0)
[32]
Hamer U, Marschner B, Brodowski S, et al. Interactive priming of black carbon and glucose mineralisation . Organic Geochemistry, 2004, 35(7): 823-830. DOI:10.1016/j.orggeochem.2004.03.003 (0)
[33]
Hassink J. The capacity of soils to preserve organic C and N by their association with clay and silt particles . Plant and Soil, 1997, 191(1): 77-87. DOI:10.1023/A:1004213929699 (0)
[34]
蔡岸冬, 徐香茹, 张旭博, 等. 不同利用方式下土壤矿物结合态有机碳特征与容量分析. 中国农业科学, 2014, 47(21): 4291-4299.
Cai A D, Xu X R, Zhang X B, et al. Capacity and characteristics of mineral associated soil organic carbon under various land uses (In Chinese). Scientia Agricultura Sinica, 2014, 47(21): 4291-4299. DOI:10.3864/j.issn.0578-1752.2014.21.014 (0)
[35]
姬强, 孙汉印, 王勇, 等. 土壤颗粒有机碳和矿质结合有机碳对4种耕作措施的响应. 水土保持学报, 2012, 26(2): 132-137.
Ji Q, Sun H Y, Wang Y, et al. Responses of soil particulate organic carbon and mineral-bound organic carbon to four kind of tillage practices (In Chinese). Journal of Soil and Water Conservation, 2012, 26(2): 132-137. (0)
[36]
唐光木, 徐万里, 周勃, 等. 耕作年限对棉田土壤颗粒及矿物结合态有机碳的影响. 水土保持学报, 2013, 27(3): 237-241.
Tang G M, Xu W L, Zhou B, et al. Effects of cultivation years on particulate organic carbon and mineral-associated organic carbon in cotton soil (In Chinese). Journal of Soil and Water Conservation, 2013, 27(3): 237-241. (0)
[37]
陈娜, 廖敏, 张楠, 等. Fe2+对水稻生长及土壤微生物活性的影响. 植物营养与肥料学报, 2014, 20(3): 651-660.
Chen N, Liao M, Zhang N, et al. Effects of exogenous ferrous on rice growth and soil microbial activities (In Chinese). Journal of Plant Nutrition and Fertilizer, 2014, 20(3): 651-660. (0)
[38]
Raich J W, Potter C S, Bhagawati D. Interannual variability in global soil respiration, 1980-94 . Global Change Biology, 2002, 8: 800-812. DOI:10.1046/j.1365-2486.2002.00511.x (0)
[39]
李英, 韩红艳, 王文娟, 等. 黄淮海平原不同土地利用方式对土壤有机碳及微生物呼吸的影响. 生态环境学报, 2017, 26(1): 62-66.
Li Y, Han H Y, Wang W J, et al. Effects of different land use types on soil organic carbon and microbial respiration in Huang-Huai-Hai Plain (In Chinese). Ecology and Environmental Sciences, 2017, 26(1): 62-66. (0)
[40]
Albuquerque A L S, mozeto A A. C:N:P ratios and stable carbon isotope compositions as indicators of organic matter sources in a riverine wetland system (Moji-Guacu River, Sao Paulo Brazil) . Wetlands, 1997, 17(1): 1-9. DOI:10.1007/BF03160713 (0)
[41]
Tanner C C, Sukias J P S, Upsdellm P. Organicmatter accumulation during maturation of gravel-bed constructed wetlands treating farm dairy waste waters . Water Research, 1998, 32(10): 3046-3054. DOI:10.1016/S0043-1354(98)00078-5 (0)
[42]
王洪丽, 孟凡涛. 试论影响森林土壤微生物活性的因素. 科技创新与应用, 2015(33): 290-290.
Wang H L, Meng F T. The factors that affect the microbial activity of forest soil (In Chinese). Technology Innovation and Application, 2015(33): 290-290. (0)
[43]
王龙昌, 玉井理, 永田雅辉, 等. 水分和盐分对土壤微生物活性的影响. 垦殖与稻作, 1998(3): 40-42.
Wang L C, Tamai R, Nagata M, et al. Effects of water and salt on soil microbial activity (In Chinese). Reclaiming and Rice Cultivation, 1998(3): 40-42. (0)
[44]
Liang C, Balser T C. Preferential sequestration of microbial carbon in subsoils of a glacial-landscape to posequence, Dane County, WI, USA . Geoderma, 2008, 148(1): 113-119. DOI:10.1016/j.geoderma.2008.09.012 (0)
[45]
周艳翔, 吕茂奎, 谢锦升, 等. 深层土壤有机碳的来源、特征与稳定性. 亚热带资源与环境学报, 2013, 8(1): 48-55.
Zhou Y X, Lv M K, Xie J S, et al. Sources, Characteristics and stability of organic carbon in deep soil (In Chinese). Journal of Subtropical Resources and Environment, 2013, 8(1): 48-55. DOI:10.3969/j.issn.1673-7105.2013.01.009 (0)
[46]
Lalonde K, Mucci A, Ouellet A, et al. Preservation of organic matter in sediments promoted by iron . Nature, 2012, 483(7388): 198-200. DOI:10.1038/nature10855 (0)
[47]
陈山.不同利用方式土壤团聚体稳定性及其与有机质和铁铝氧化物的关系.武汉: 华中农业大学, 2012
Chen S. Stability of soil aggregates under different land use patterns and relationships with organic matter and iron-aluminum oxides (In Chinese). Wuhan: Huazhong Agricultural University, 2012 http://www.wanfangdata.com.cn/details/detail.do?_type=degree&id=Y2161850 (0)
[48]
郭杏妹, 吴宏海, 罗媚, 等. 红壤酸化过程中铁铝氧化物矿物形态变化及其环境意义. 岩石矿物学杂志, 2007, 26(6): 515-521.
Guo X M, Wu H H, Luo M, et al. The morphological change of Fe/Al-oxide minerals in red soils in the process of acidification and its environmental significance (In Chinese). Acta Petrologica et Mineralogica, 2007, 26(6): 515-521. DOI:10.3969/j.issn.1000-6524.2007.06.008 (0)
[49]
王清奎, 汪思龙. 土壤团聚体形成与稳定机制及影响因素. 土壤通报, 2005, 36(3): 415-421.
Wang Q K, Wang S L. Forming and stable mechanism of soil aggregate and influencing factor (In Chinese). Chinese Journal of Soil Science, 2005, 36(3): 415-421. DOI:10.3321/j.issn:0564-3945.2005.03.031 (0)
[50]
Barral M T, Arias M, Guérif J. Effects of iron and organicmatter on the porosity and structural stability of soil aggregates . Soil & Tillage Research, 1998, 46(3/4): 261-272. (0)
[51]
Goldberg S. Effect of saturating cation, pH, and aluminum and iron oxide on the flocculation of kaolinite and montmorilloinite . Clays and Clay Minerals, 1987, 35(3): 220-227. DOI:10.1346/CCMN (0)
[52]
谭文峰, 周素珍, 刘凡, 等. 土壤中铁铝氧化物与黏土矿物交互作用的研究进展. 土壤, 2007, 39(5): 726-730.
Tan W F, Zhou S Z, Liu F, et al. Advancement in the study on interactions between iron-aluminum (Hydro-) oxides and clay minerals in soil (In Chinese). Soils, 2007, 39(5): 726-730. DOI:10.3321/j.issn:0253-9829.2007.05.009 (0)
[53]
Kleber M, Mikutta R, Torn M S, et al. Poorly crystalline mineral pH area protect organic matter in acid subsoil horizons . European Journal of Soil Science, 2005, 56(6): 717-725. (0)
[54]
汪超. 黑垆土有机碳在团聚体中的分配及其保护机制. 土壤, 2015, 47(1): 49-54.
Wang C. Distribution and preservation mechanisms of organic carbon in aggregates of Heilu soil (In Chinese). Soils, 2015, 47(1): 49-54. (0)
[55]
胡国成, 章明奎. 氧化铁对土粒强胶结作用的矿物学证据. 土壤通报, 2002, 33(1): 25-27.
Hu G C, Zhang M K. Mineralogical evidence for strong cementation of soil particles by iron oxides (In Chinese). Chinese Journal of Soil Science, 2002, 33(1): 25-27. DOI:10.3321/j.issn:0564-3945.2002.01.007 (0)
[56]
Hou T, Xu R K, Zhao A Z. Interaction between electric double layers of kaolinite and Fe/Al oxides in suspensions . Journal of Colloid & Interface Science, 2007, 310(2): 670. (0)
[57]
邵宗臣, 陈家坊. 几种氧化铁的离子吸附特性研究. 土壤学报, 1984, 21(2): 153-162.
Shao Z C, Chen J F. Study on ion adsorption characteristics of some iron oxides (In Chinese). Acta Pedologica Sinica, 1984, 21(2): 153-162. (0)
[58]
王小红, 杨智杰, 刘小飞, 等. 中亚热带山区土壤不同形态铁铝氧化物对团聚体稳定性的影响. 生态学报, 2016, 36(9): 2588-2596.
Wang X H, Yang Z J, Liu X F, et al. Effects of different forms of Fe and Al oxides on soil aggregate stability in mid-subtropical mountainous area of southern China (In Chinese). Acta Ecological Sinica, 2016, 36(9): 2588-2596. (0)
[59]
Six J, Bossuyt H, Degryze S, et al. A history of research on the link between (micro)aggregates, soil biota, and soil organic matter dynamics . Soil & Tillage Research, 2004, 79(1): 7-31. (0)
[60]
Kaiser K, Guggenberger G. The role of DOM sorption tomineral surfaces in the preservation of organicmatter in soils . Organic Geochemistry, 2000, 31(7): 711-725. (0)
[61]
Wagai R, Mayer L. Sorptive stabilization of organicmatter in soils by hydrous iron oxides . Geochimica Et Cosmochimica Acta, 2007, 71(1): 25-35. DOI:10.1016/j.gca.2006.08.047 (0)
[62]
Han L F, Sun K, Jin J, et al. Some concepts of soil organic carbon characteristics andmineral interaction from a review of literature . Soil Biology and Biochemistry, 2016, 94: 107-121. DOI:10.1016/j.soilbio.2015.11.023 (0)
[63]
Riedel T, Zak D, Biester H, et al. Iron traps terrestrially derived dissolved organicmatter at redox interfaces . Proceedings of the National Academy of Sciences of the United States of America, 2013, 110(25): 10101-10105. DOI:10.1073/pnas.1221487110 (0)
[64]
Chen C, Dynes J J, Wang J, et al. Properties of fe-organicmatter associations via coprecipitation versus adsorption . Environmental Science and Technology, 2014, 48(23): 13751-13759. DOI:10.1021/es503669u (0)
[65]
Mikutta R, Lorenz D, Guggenberger G, et al. Properties and reactivity of Fe-organic matter associations formed by coprecipitation versus adsorption:Clues from arsenate batch adsorption . Geochimica et Cosmochimica Acta, 2014, 144: 258-276. DOI:10.1016/j.gca.2014.08.026 (0)
[66]
Ransom B, Bennett R H, Baerwald R, et al. TEM study of in situ organicmatter on continentalmargins:Occurrence and the "monolayer" hypothesis . Marine Geology, 1997, 138(1/2): 1-9. (0)
[67]
Guggenberger G, Kaiser K. Dissolved organicmatter in soil:challenging the paradigm of sorptive preservation . Geoderma, 2003, 113(3): 293-310. (0)
[68]
Nierop K G J, Jansen B, Verstraten J M. Dissolved organic matter, aluminium and iron interactions:Precipitation induced by metal/carbon ratio, pH and competition . Science of the Total Environment, 2002, 300(1/2/3): 201-211. (0)
[69]
徐基胜, 赵炳梓. 可溶性有机碳在典型土壤上的吸附行为及机理. 土壤, 2017, 49(2): 314-320.
Xu J S, Zhao B Z. Mechanisms of dissolved organic carbon adsorption on different typical soils in China (In Chinese). Soils, 2017, 49(2): 314-320. (0)
[70]
Kothawala D N, Moore T R, Hendershot W H. Soil properties controlling the adsorption of dissolved organic carbon to mineral soils . Soil Science Society of America Journal, 2009, 73(6): 1831-1842. DOI:10.2136/sssaj2008.0254 (0)
[71]
李太魁, 王小国, 朱波. 紫色土可溶性有机碳的吸附-解吸特征. 农业环境科学学报, 2012, 31(4): 721-727.
Li T K, Wang X G, Zhu B. Adsorption and desorption characteristics of dissolved organic carbon(DOC)on the purple soils (In Chinese). Journal of Agro-Environment Science, 2012, 31(4): 721-727. (0)
[72]
Kögelknabner I, Guggenberger G, Kleber M, et al. Organo-mineral associations in temperate soils:Integrating biology, mineralogy, and organic matter chemistry . Journal of Plant Nutrition and Soil Science, 2008, 171(1): 61-82. DOI:10.1002/(ISSN)1522-2624 (0)
[73]
Paul E A. The nature and dynamics of soil organicmatter:Plant inputs, microbial transformations, and organicmatter stabilization . Soil Biology & Biochemistry, 2016, 98: 109-126. (0)
[74]
赵彬, 姚鹏, 于志刚. 有机碳-氧化铁结合对海洋环境中沉积有机碳保存的影响. 地球科学进展, 2016, 31(11): 1151-1158.
Zhao B, Yao P, Yu Z G. The effect of organic carbon-iron oxide association on the preservation of sedimentary organic carbon in marine environments (In Chinese). Advances in Earth Science, 2016, 31(11): 1151-1158. (0)
[75]
Widdel F, Schnell S, Heising S, et al. Ferrous iron oxidation by anoxygenic phototrophic bacteria . Nature, 1993, 362(6423): 834-836. DOI:10.1038/362834a0 (0)
[76]
陈蕾, 张洪霞, 李莹, 等. 微生物在地球化学铁循环过程中的作用. 中国科学:生命科学, 2016, 46(9): 1069-1078.
Chen L, Zhang H X, Li Y, et al. The role of microorganisms in the geochemical iron cycle (In Chinese). Scientia Sinica (Vitae), 2016, 46(9): 1069-1078. (0)
[77]
Melton E D, Swanner E D, Behrens S, et al. The interplay of microbially mediatedand abiotic reactions in the biogeochemical Fe cycle . Nature Reviews Microbiology, 2014, 12: 797-808. DOI:10.1038/nrmicro3347 (0)
[78]
Lovley D R, Phillips E J P. Competitive mechanisms for inhibition of sulfate reduction and methane production in the zone of ferric iron reduction in sediments . Applied & Environmental Microbiology, 1987, 53: 2636-2641. (0)
[79]
Bond D R, Lovley D R. Reduction of Fe(Ⅲ) oxide by methanogens in the presence and absence of extracellular quinones . Environmental Microbiology, 2002, 4(2): 115-124. DOI:10.1046/j.1462-2920.2002.00279.x (0)
[80]
胡敏, 李芳柏. 土壤微生物铁循环及其环境意义. 土壤学报, 2014, 51(4): 683-698.
Hu M, Li F B. Soil microbe mediated iron cycling and its environmrntal implication (In Chinese). Acta Pedologica Sinica, 2014, 51(4): 683-698. (0)
[81]
Castro H, Fortunel C, Freitas H. Effects of land abandonment on plant litter decomposition in a Montado system:Relation to litter chemistry and community functional parameters . Plant and Soil, 2010, 333(1/2): 181-190. (0)
[82]
Kara O, Baykara M. Changes in soil microbial biomass and aggregate stability under different land uses in the northeastern Turkey . Environmental Monitoring and Assessment, 2014, 186(6): 3801-3808. DOI:10.1007/s10661-014-3658-0 (0)
[83]
钟文辉, 蔡祖聪. 土壤管理措施及环境因素对土壤微生物多样性影响研究进展. 生物多样性, 2004, 12(4): 456-465.
Zhong W H, Cai Z C. Effect of soil management practices and environmental factors on soil microbial diversity:A review (In Chinese). Biodiversity Science, 2004, 12(4): 456-465. DOI:10.3321/j.issn:1005-0094.2004.04.010 (0)
[84]
汪桂芝.不同价态铁元素对厌氧微生物降解2, 4, 6-三氯酚的影响及特性研究.湖南湘潭: 湘潭大学, 2013
Wang G Z. Effect and characteristic of different valence forms of iron on 2, 4, 6-trichlorophenol degradation by anaerobic microorganism (In Chinese). Xiangtan, Hunan: Xiangtan University, 2013 http://cdmd.cnki.com.cn/Article/CDMD-10530-1013380042.htm (0)
[85]
Kaiser K, Zech W. Soil dissolved organic matter sorption as influenced by organic and sesquioxide coatings and sorbed sulfate . Soil Science Society of America Journal, 1998, 62(1): 129-136. DOI:10.2136/sssaj1998.03615995006200010017x (0)
Progress in Researches on Effect of Iron Promoting Accumulation of Soil Organic Carbon
WANG Luying1,2 , QIN Lei1 , LÜ Xianguo1 , JIANG Ming1 , ZOU Yuanchun1     
1. Key Laboratory of Wetland Ecology and Environment & Jilin Provincial Joint Key Laboratory of Changbai Mountain Wetland and Ecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China;
2. University of Chinese Academy of Sciences, Beijing 100049, China
Abstract: The content of total organic carbon in soil is a major indicator reflecting the content of total organic matter and further on soil fertility. There are numerous factors that affect accumulation of organic carbon in soil. Among them, iron plays an essential role in "capturing" organic carbon and forming "rust sink", thus promoting accumulation of soil organic carbon. A number of scholars have studied stabilizing mechanisms of soil organic carbon. In this paper, attempts were made to summarize the studies that had been done. It is found that the stabilizing mechanisms mainly include physical preservation of aggregates, chemical preservation of minerals, biological preservation of microorganisms and preservation of organic carbon per se. Among the four mechanisms, the first two are the main ones. Iron is closely involved in the mechanisms of physical, chemical and biological preservations. In physical preservation, iron promotes formation of soil aggregates. In chemical preservation, iron adsorbs and precipitates with organic carbon. At the same time, iron affects activity of soil microorganisms in biological preservation. All indicate that iron plays an important role in soil organic carbon accumulation. And the protective effect of organic carbon per se is mainly reflected in the anti-decomposition of a certain portion of organic carbon. In the end, the authors put forward several suggestions. More attention should be paid to the mechanisms of organic carbon sequestration and functional recovery of the carbon sink in the soil systems that are active in oxidation reduction and remarkable in ecological service function, to quantitative researches on and comparison between the different mechanisms in importance, and to simulation experiments, so as to better realize the goal of theory serving practice.
Key words: Soil organic carbon    Iron oxide    Aggregate    Co-precipitation    Adsorption    Microorganism