,, 王立春,吉林省农业科学院农业资源与环境研究所,长春 130033Effects of Corn Straw Returning Amounts on Carbon Sequestration Efficiency and Organic Carbon Change of Soil and Aggregate in the Black Soil Area
GAO HongJun, PENG Chang, ZHANG XiuZhi, LI Qiang, ZHU Ping,, WANG LiChun,Institute of Agricultural Resources and Environment, Jilin Academy of Agricultural Sciences, Changchun 130033通讯作者:
责任编辑: 李云霞
收稿日期:2020-03-23接受日期:2020-04-27网络出版日期:2020-11-16
| 基金资助: |
Received:2020-03-23Accepted:2020-04-27Online:2020-11-16
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高洪军,Tel：0431-87063170;E-mail：ghj-
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高洪军, 彭畅, 张秀芝, 李强, 朱平, 王立春. 秸秆还田量对黑土区土壤及团聚体有机碳变化特征和 固碳效率的影响[J]. 中国农业科学, 2020, 53(22): 4613-4622 doi:10.3864/j.issn.0578-1752.2020.22.008
GAO HongJun, PENG Chang, ZHANG XiuZhi, LI Qiang, ZHU Ping, WANG LiChun.
开放科学（资源服务）标识码（OSID）：
0 引言
【研究意义】农田土壤有机碳和土壤团聚体特征是评价土壤肥力的重要指标,它们影响着土壤的物理、化学、生物等土壤性质[1,2],也是土壤中各种养分的贮藏库及肥力供应的核心物质[3]。因此,探明黑土区农田土壤及团聚体固碳效应对于土壤肥力提升及玉米增产稳产均具有重要意义。【前人研究进展】土壤固碳效率可以反映单位外源有机碳在土壤或团聚体中的转化程度[4]。美国及加拿大温带地区土壤固碳效率为14%—21%[5],而印度热带半干旱地区土壤固碳效率为25%[6]。ZHANG等[7]根据6个长期土壤肥力定位试验计算了我国不同类型土壤的固碳效率,其中：新疆灰漠土固碳效率为26.7%、吉林公主岭黑土为15.8%、河南潮土为6.8%,并且土壤固碳量都与累积有机碳投入呈极显著的线性正相关关系,很多研究结果也支持这一观点[8,9]。然而,CAMPBELL 等[10]研究认为,当外源有机碳长期投入在土壤有机碳含量高的农田上,土壤有机碳含量并不持续增加,而是达到一个稳定碳饱和点之后不再继续增加。秸秆有机碳输入对土壤大团聚体（＞0.25 mm）有机碳的增加贡献较大,对小粒级团聚体有机碳含量影响较小[11]。李景等[12]通过15年的秸秆覆盖还田试验研究也表明,外源碳累积投入量与＞0.25 mm大团聚体有机碳储量变化量呈极显著的正相关关系,其中大粒级团聚体固碳效率较高,而小粒级团聚体固碳能力较弱。除土壤类型、气候因素、耕作和种植制度外,施用农家肥和秸秆还田也是影响农田土壤有机碳转化和固持的最重要因素之一[13]。东北地区是我国重要的玉米生产区之一,秸秆资源十分丰富,秸秆还田能显著提高土壤有机碳含量,进而改善土壤团聚体有机碳的分布[14]。【本研究切入点】目前关于不同培肥及耕作措施对土壤有机碳变化规律和团聚体特征影响研究较多,对土壤总有机碳固持效率研究也有报道,但关于玉米秸秆还田对东北黑钙土团聚体固碳效率机制等研究比较薄弱,需进一步探讨和明确。【拟解决的关键问题】本文基于7年的秸秆还田量试验,探讨不同玉米秸秆还田量对土壤固碳效应的影响,进而阐明秸秆碳输入与土壤及团聚体碳储量的量化关系;深入剖析各粒级团聚体固碳效应,以期揭示农田土壤有机碳固持效率机制,为定量提升土壤有机碳及土壤肥力培育提供借鉴与参考。1 材料与方法
1.1 试验区概况
试验地位于吉林省农安县哈拉海镇吉林省农业科学院哈拉海试验站,该区域属中温带大陆性季风气候,光热资源充足,地势平坦,四季分明,年平均日照时数为2 620 h,年均气温4.7℃,无霜期145 d,年均降雨量507.7 mm,有效积温2 800℃。于2012年4月设置为田间定位试验,土壤类型为黑钙土,在该区域具有典型代表性。试验开始时耕层（0—20 cm）土壤基础化学性状[15]：有机质为22.3 g·kg-1,全氮1.537 g·kg-1,全磷 0.565 g·kg-1,全钾 22.7 g·kg-1,碱解氮 128.2 mg·kg-1,速效磷 12.9 mg·kg-1,速效钾 132.5 mg·kg-1,pH 7.75。1.2 试验设计
试验共设4个处理,按照施用0、4 500、9 000、13 500 kg·hm-2玉米秸秆量进行设计,分别为：（1）秸秆还田量0（SA0）;（2）秸秆还田量4 500 kg·hm-2（SA300）;（3）秸秆还田量9 000 kg·hm-2（SA600）;（4）秸秆还田量13 500 kg·hm-2（SA900）,其中9 000 kg·hm-2秸秆还田量为当地农户的还田量。每处理3次重复,随机区组排列,小区面积为80 m2。其中,秸秆还田方式为旋耕还田：在玉米机械收获后,根据玉米秸秆不同施用量对各小区进行人工撒施秸秆,然后利用秸秆粉碎机粉碎秸秆（长度小于6 cm）,并采用大马力农机对秸秆进行深旋还田,深度约16 cm,达到秸秆与土壤充分均匀混合,最后重镇压。试验供试肥料：尿素（N 46%）、重过磷酸钙（P2O5 46%）和硫酸钾（K2O 50%）;各处理氮、磷、钾肥施用量相同,分别为N 210、P2O5 105、K2O 105 kg·hm-2。1/3的氮肥和全部磷钾肥在春季播种前作底肥施用,余下2/3 氮肥在玉米拔节期追肥。玉米秸秆养分含量：C 42.6%、N 0.8%、P2O5 0.32%和K2O 0.75%。供试玉米品种为先玉335;每年玉米在4月28日左右播种,种植密度6.5万株/hm2,9月27日左右收获,其他田间管理措施按当地生产田进行[15]。
1.3 土壤有机碳和团聚体样品采集及分析
2014—2018年秋季收获后,对每个小区采集耕层土样（0—20 cm）,按“S”形取5个点土样,然后组成一个混合土样。土壤风干过筛后采用重铬酸钾-外加热法测定土壤有机碳。2018年10月在玉米收获后采集0—20 cm土层样品进行团聚体分级。土壤团聚体分级依据ELLIOT[16]的湿筛法,分离出＞2 mm,2—0.25 mm,0.25—0.053 mm和＜0.053 mm 等4个级别团聚体。＞0.25 mm的团聚体称为水稳性大团聚体,＜0.25 mm称为水稳性微团聚体。土壤有机碳含量及分离得到的各粒级团聚体有机碳含量采用EA3000元素分析仪测定。
1.4 计算方法
外源有机碳投入量计算方法参照JIANG 等[17];有机碳储量及团聚体有机碳储量计算方法参照李景等[12];土壤总有机碳及各粒级团聚体有机碳的固碳速率和固碳效率采用公式（1）—（3）[18]：式中,SOCstock-t、SOCstock-c和ΔSOCstock分别代表处理有机碳储量、对照有机碳储量和有机碳储量的增加量;Cinput-t和Cinput-c分别代表处理和对照外有机碳输入量;n代表外源有机碳输入的累积年份;SOCSR和SOCSE分别代表土壤固碳速率和固碳效率。
1.5 数据处理
试验数据和图表采用Excel 进行处理,用SAS 9.0 软件进行两因素方差分析,处理间多重比较采用LSD-test 法进行差异显著性检验。采用简单线性关系（y=ax+b）来拟合土壤及团聚体有机碳增加量与外源有机碳输入的相关关系,并用t 检验斜率的差异显著性。2 结果
2.1 不同秸秆还田量对土壤有机碳含量的影响
不同秸秆还田量对土壤有机碳含量影响显著（图1）,2014—2018年秸秆还田SA600和SA900两处理土壤有机碳含量均显著高于秸秆不还田（SA0）、低量秸秆还田（SA300）处理;从第5年（2016年）秸秆还田开始,SA900和SA600两处理土壤有机碳含量差异达显著水平（P＜0.05）。高量秸秆还田（SA900）处理5年间土壤有机碳较秸秆不还田（SA0）处理分别依年限增加了9.3%、11.0%、15.8%、17.2%、23.1%;在秸秆还田前4年（2012—2015年）,低量秸秆还田SA300处理土壤有机碳与SA0处理相比差异不显著;但在秸秆还田后3年（2016—2018年）,两者之间达到差异显著水平（P＜0.05）。总体上,不同秸秆还田量下土壤有机碳含量由高到低依次表现为SA900、SA600、SA300、SA0。图1
新窗口打开|下载原图ZIP|生成PPT图1不同秸秆还田量下土壤有机碳的变化
Fig. 1Changes of soil organic carbon under different straw returning amounts
2.2 不同秸秆还田量对土壤固碳效率变化的影响
由图2分析可知,各处理外源累积碳的投入增加量、以及土壤有机碳储量变化量均存在较大差异,秸秆不还田（SA0）处理外源有机碳的增加仅归功于玉米地上残茬及根系生物量的投入,累积碳投入量达到10.92 t·hm-2;而秸秆还田处理土壤中的有机物料源于收获植株的秸秆还田、玉米地上残茬及根系生物量,其中,SA900处理累积碳投入量较SA0处理增加35.12 t·hm-2。随着秸秆碳的累积输入各处理的有机碳储量均有所提高,其中,高量秸秆还田（SA900）处理的有机碳储量最高,较秸秆不还田（SA0）处理土壤有机碳储量（2018年）增加4.74 t·hm-2。由图2可知,土壤总有机碳储量与外源有机碳输入呈极显著正线性相关关系（P＜0.01）,即土壤总有机碳储量随外源碳投入量增加而显著提高;土壤的固碳效率为12.9%,即农田投入100 t·hm-2外源有机碳,土壤有机碳储量增加12.9 t·hm-2。当有机碳储量变化（y）为0时,每年需投入秸秆碳1.08 t·hm-2（或干秸秆2.54 t·hm-2）维持初始土壤SOC水平,土壤有机碳储量达到平衡。表明秸秆还田对维持和提高土壤有机碳含量具有重要作用。
图2
新窗口打开|下载原图ZIP|生成PPT图2外源累积碳投入与土壤有机碳储量变化的响应关系
Fig. 2Relative relationship between change of organic carbon stocks and cumulative carbon input
2.3 不同秸秆还田量对土壤团聚体有机碳含量及储量的影响
2.3.1 对土壤团聚体有机碳含量的影响 由图3分析可知,各粒级团聚体大小差异性影响着团聚体碳含量,以2—0.25 mm大粒级团聚体有机碳含量为最高,各处理平均达到15.8 g·kg-1;0.25—0.053 mm和＜0.053 mm小粒级团聚体有机碳含量最低,两个粒级各处理平均值分别为10.5和11.9 g·kg-1。表明大团聚体较微团聚体能储存更多的有机碳。与秸秆不还田（SA0）相比,对于＞2 mm和2—0.25 mm粒级大团聚体,秸秆还田处理都显著提高了该粒级团聚体有机碳含量（P＜0.05）,其中,3个秸秆还田量处理之间差异达显著水平;对于0.25—0.053 mm和＜0.053 mm粒级微团聚体,秸秆还田（SA600）和（SA900）两处理均显著提高了该粒级团聚体有机碳含量（P＜0.05）,但秸秆还田SA300和SA0两处理之间差异未达到显著水平。高量秸秆还田（SA900）各粒级团聚体碳含量较其他3个处理都有显著增加（P＜0.05）,较SA0处理提高幅度为2.3%—22.7%,其中在2—0.25 mm和＜0.053 mm粒级中增加幅度最高。表明秸秆还田不仅有利于大团聚体（＞0.25 mm）中有机碳的增加,同时也显著提高了微团聚体有机碳含量,尤其高量秸秆还田对土壤团聚体有机碳含量提高贡献更大。
2.3.2 对表层土壤团聚体有机碳储量的影响 由图4分析可知,0.25—0.053 mm 粒级团聚体有机碳储量为最高,平均为12.92 t·hm-2,其次为2—0.25 mm（10.32 t·hm-2）,而＞2 mm和＜0.053 mm粒级团聚体储量为最低。与秸秆不还田相比,秸秆还田SA600和SA900两处理均明显提高了＞2 mm 和2—0.25mm粒级大团聚体有机碳储量,但没有显著提高＜0.25 mm微团聚体有机碳储量;高量秸秆还田SA900处理的＞2 mm和2—0.25 mm粒级团聚体有机碳储量较秸秆不还田（SA0）分别提高了45.5%和47.7%;＜0.053 mm粒级微团聚体碳储量对不同秸秆还田量的影响没有变化。表明秸秆还田不仅有利于大团聚体有机碳储量的增加,而且秸秆还田数量也影响着土壤团聚体有机碳储量的变化。
图3
新窗口打开|下载原图ZIP|生成PPT图3不同秸秆还田量下各粒级团聚体有机碳含量
Fig. 3Aggregates organic carbon content under different straw returning amounts
图4
新窗口打开|下载原图ZIP|生成PPT图4不同秸秆还田量下各粒级团聚体有机碳储量变化
Fig. 1Changes of Aggregates organic carbon stocks under different straw returning amounts
2.4 不同秸秆还田下各粒级团聚体有机碳固持速率与固碳效率
2.4.1 不同粒级团聚体有机碳固持速率 不同秸秆还田量对0—20 cm土层各粒级团聚体有机碳储量的固持速率影响差异较大（表1）。＞2 mm和2—0.25 mm各粒级大团聚体有机碳在秸秆还田3个处理中平均固碳速率分别为0.15和0.45 t·hm-2·a-1,并明显高于0.25—0.053 mm和＜0.053 mm各粒级微团聚体固碳速率。秸秆还田SA900和SA600处理＞2 mm和2—0.25 mm粒级大团聚体固碳速率明显高于秸秆不还田（SA0）和低量还田（SA300）处理;在微团聚体0.25—0.053 mm和＜0.053 mm粒级中,各处理土壤固碳速率差异不显著。Table 1
表1
表1各粒级团聚体有机碳固持速率（2018）
Table 1
| 处理 Treatment | 累积碳输入量 Cumulative C input (t·hm-2) | 各粒级团聚体固碳速率 Sequestrated rates of aggregates organic carbon (t·hm-2·a-1) | |||
|---|---|---|---|---|---|
| ＞2 mm | 2—0.25 mm | 0.25—0.053 mm | ＜0.053 mm | ||
| SA0 | 10.92 | ||||
| SA300 | 22.40 | 0.05±0.02c | 0.13±0.01c | 0.02±0.02a | 0.01±0.02a |
| SA600 | 34.62 | 0.16±0.03b | 0.56±0.04b | 0.03±0.02a | 0.01±0.01a |
| SA900 | 46.04 | 0.25±0.01a | 0.66±0.03a | 0.07±0.02a | 0.03±0.02a |
| 平均值 Average | 0.15 | 0.45 | 0.04 | 0.01 | |
新窗口打开|下载CSV
2.4.2 不同粒级团聚体有机碳固持效率 随着连续7年外源有机碳累积输入下,＞2 mm、2—0.25 mm和0.25—0.053 mm各粒级团聚体碳储量均显著提高（P＜0.05）,图5）,表明这些粒级团聚体中有机碳均没有出现碳饱和现象。＜0.053 mm粒级团聚体有机碳储量并未随累积碳投入量的增加而增加,表现出碳饱和迹象。图5中的直线斜率表示各粒级团聚体固碳效率,斜率越大固碳效率也越大。2—0.25 mm粒级团聚体的固碳效率为最高,显著高于其他各粒级团聚体固碳效率（P＜0.05）,固碳效率为13.6%;其次为＞2 mm 粒级团聚体,固碳效率为4.9%;0.25—0.053 mm和＜0.053 mm粒级微团聚体固碳效率为最低。表明不同粒级团聚体有机碳以2—0.25 mm粒级大团聚体对秸秆还田响应最敏感,对土壤总有机碳储量的增加起决定性作用,可作为表征土壤有机碳响应土壤管理措施变化指标。
图5
新窗口打开|下载原图ZIP|生成PPT图5不同粒级团聚体有机碳储量增加量与累积碳投入量的关系（2018）
Fig. 5Relationship between organic carbon stocks of soil aggregates and cumulative C input
3 讨论
3.1 土壤总有机碳变化及固碳效率
秸秆还田和有机肥等外源有机碳的输入是农田土壤有机碳增加的主要途径和碳源[19]。许多研究表明长期秸秆还田能显著提高土壤有机碳含量[20,21]。本研究中,秸秆还田SA600和SA900两处理土壤有机碳含量均显著高于秸秆不还田（SA0）、低量秸秆还田（SA300）,并且后3年SA900和SA600两处理土壤有机碳含量差异显著（P＜0.05）。同时,随着玉米秸秆还田量增加和还田时间的延长,土壤有机碳含量逐渐明显提升。关于土壤有机碳是否随着秸秆还田量的增加而同步提高,文献报道也存在着一些差异。有许多****认为,随着秸秆还田量的增加,土壤有机碳含量和碳库活度均增加,并与秸秆还田量呈极显著线性正相关关系[22,23],这与本研究结果一致。但白建忠等[24]在水旱轮作农田上研究发现,秸秆还田对年际间水旱轮作农田土壤有机质提升并不呈叠加效应,而且土壤有机质也不随秸秆还田量增加而同步提高,因为过量秸秆还田降低了土壤pH及秸秆的腐解速率,从而不利于土壤有机碳累积[25]。有****研究表明[26],土壤有机碳储量对系统的碳输入水平的提升无显著响应,但大量研究表明[7,27],土壤总有机碳储量与外源有机碳输入呈极显著正线性相关关系（P＜0.01）,这与本研究结果一致,黑钙土土壤固碳效率为12.9%,土壤有机碳尚未达到碳饱和点,还存在很大的固碳空间,该结果略低于张文菊等[7]在吉林省公主岭黑土长期定位试验的研究结果（固碳效率为15.8%）,但要高于河南潮土（6.8%）,江西红壤（8.1%）[19],这主要是由于土壤质地、气候因素（温度和水分）和有机物料种类及施用方式等诸多因素造成土壤固碳效率差异较大;如公主岭土壤固碳效率比农安高,可能是施用有机物料类型不同造成的,公主岭处理施用农家肥,而农安处理为秸秆还田,施用农家肥土壤固碳速率显著高于秸秆还田[28],施用农家肥不仅可显著提高土壤有机质含量,而且农家肥本身是处于半分解状态的有机质,有利于土壤碳的固持;也可能是由于公主岭典型黑土比黑钙土质地黏粒含量高,黏粒吸附能力强、比表面积较大、固碳能力强,所以黏粒固碳效率明显高于砂粒和粉粒,这与蔡岸冬等[17]在红壤长期定位施肥试验报道的结果相似。
3.2 各粒级团聚体对土壤有机碳的固持
土壤团聚化过程是土壤团聚体固碳的重要驱动途径[29]。本研究发现,各粒级团聚体有机碳含量以2—0.25 mm和＞2 mm粒级大团聚体有机碳含量为最高。与秸秆不还田（SA0）相比,秸秆还田SA600和SA900两处理均显著提高了各粒级团聚体有机碳含量（P＜0.05）,尤其是对大团聚体（＞0.25 mm）有机碳含量增加贡献更大;其中3个秸秆还田量处理各粒级团聚体碳含量之间差异达显著水平,这与本人前期报道[15]的不同秸秆还田模式对黑钙土团聚体特征的影响研究结果一致。刘恩科等[30]研究也认为,长期有机肥和化肥配施可明显提高各粒级团聚体有机碳含量,尤其是对大团聚体有机碳含量增加贡献更大。这是由于秸秆还田能促进土壤有机碳的积累,腐殖质作为主要胶结物质将土壤颗粒和小级别团聚体胶结成大团聚体,从而提高了大团聚体有机碳含量[31]。所以,＞0.25 mm粒级大团聚体有机碳对农业管理措施的变化更灵敏,可作为评价土壤有机碳变化对不同土壤培肥措施快速响应的重要指标。KOOL等[32]提出不同碳库存在等级饱和模型,随着外源碳输入量的增加,各粒级团聚体由最小粒级到最大粒级依次逐渐达到碳饱和,最终土壤碳库饱和。本研究结果也支持了这种饱和理论,随秸秆碳输入量的增加,＜0.053 mm粒级团聚体碳储量没有增加,0.25—0.053 mm粒级团聚体碳储量增加不明显,而2—0.25 mm和＞2 mm粒级团聚体有机碳储量增加显著。本研究也发现,＞2 mm、2—0.25 mm和0.25—0.053 mm各粒级土壤团聚体有机碳储量增加量与累积碳投入量增加量呈显著正线性关系,表明这些粒级团聚体中有机碳均没有出现碳饱和现象,而＜0.053 mm粒级团聚体有机碳出现碳饱和迹象。这是由于微团聚体中固持的碳稳定性强、周转较慢,固碳能力有限,新输入的颗粒有机碳主要分布在大团聚体中。
不同粒级土壤团聚体周转对土壤固碳效率高低具有决定性的作用[31]。大粒级团聚体固碳效率显著高于小粒级团聚体,＞2 mm 和2—0.25 mm粒级固碳效率分别为4.9%和13.6%。而0.25—0.053 mm和＜0.053 mm粒级微团聚体固碳速率和固碳效率均为最低。随着秸秆碳的增加＜0.053 mm粒级微团聚体固碳效率并没有同步增加。李景等[12]研究结果表明,长期秸秆覆盖还田更有利于大团聚有机碳储量的增加,＞2 mm粒级团聚体固碳效率为最高,这可能是由于秸秆还田增加了新鲜植物残体有机碳,通过有机质的胶结作用形成大团聚体并增加其有机碳含量,更多的有机碳被大团聚体保护起来,进而提高其固碳效率[33]。
3.3 土壤固碳效率在土壤有机碳定量提升中的应用与预测
通过土壤对不同有机物料碳的固持效率,可以计算出提升和维持有机碳水平的外源有机物料施用量。以玉米秸秆还田为例,根据表2该地区秸秆还田下土壤固碳效率为12.9%,以0—20 cm土层土壤SOC储量等于33 t·hm-2（初始SOC储量）为基础计算秸秆还田投入量,要维持该地区土壤有机碳储量平衡,每年最低需投入玉米风干秸秆（有机碳含量约为42.7%,含水量约为14%）约2.54 t·hm-2;如未来10年内,土壤有机碳储量要提升10%、20%、30%,预测每年需额外分别投入风干玉米秸秆约5.99、11.98、17.97 t·hm-2。Table 2
表2
表2土壤有机碳储量提升所需玉米秸秆投入量及相关参数
Table 2
| 有机碳储量 SOC stocks (t·hm-2) | 每年提升碳储量 Increased SOC stocks (t·hm-2·a-1) | 固碳效率 C sequestration efficiency (%) | 年所需碳投入量 Carbon input (t·hm-2·a-1) | 年所需投入玉米秸秆量 Corn straw input (t·hm-2·a-1) | |
|---|---|---|---|---|---|
| 初始值 Initial value | 33 | 0 | |||
| 10年提升10% Increased by 10% over 10 years | 36.3 | 0.33 | 12.9 | 2.56 | 5.99 |
| 10年提升20% Increased by 20% over 10 years | 39.6 | 0.66 | 12.9 | 5.12 | 11.98 |
| 10年提升30% Increased by 30% over 10 years | 42.9 | 0.99 | 12.9 | 7.67 | 17.97 |
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4 结论
秸秆还田量9 000—13 500 kg·hm-2土壤的固碳效果较好,有效促进了黑土区土壤有机碳的累积与固定,并且土壤有机碳含量均随秸秆还田量以及还田年限的延长而增加。土壤总有机碳储量与外源有机碳输入呈极显著正线性相关关系（P＜0.01）,该土壤固碳效率为12.9%。秸秆还田不仅有利于大团聚体有机碳储量的增加,而且秸秆还田数量也影响着各粒级土壤团聚体有机碳储量的转化。随着秸秆碳累积投入量的增加,各粒级团聚体存在明显的由最小粒级到最大粒级依次逐渐达到碳饱和等级顺序;除＜0.053 mm粒级团聚体外,其他各粒级团聚体中有机碳均没有出现明显的碳饱和迹象,各粒级团聚体固碳效率最高的为2—0.25 mm和＞2 mm粒级大团聚体,固碳效率分别为13.6%和4.9%。＞0.25 mm粒级大团聚体有机碳对外源碳投入量的影响更灵敏,可作为表征土壤有机碳响应土壤培肥措施的变化指标。参考文献 原文顺序
文献年度倒序
文中引用次数倒序
被引期刊影响因子
[本文引用: 1]
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DOI:10.1038/nature10386URLPMID:21979045 [本文引用: 1]
Globally, soil organic matter (SOM) contains more than three times as much carbon as either the atmosphere or terrestrial vegetation. Yet it remains largely unknown why some SOM persists for millennia whereas other SOM decomposes readily--and this limits our ability to predict how soils will respond to climate change. Recent analytical and experimental advances have demonstrated that molecular structure alone does not control SOM stability: in fact, environmental and biological controls predominate. Here we propose ways to include this understanding in a new generation of experiments and soil carbon models, thereby improving predictions of the SOM response to global warming.
[本文引用: 1]
DOI:10.1016/j.still.2013.01.013URL [本文引用: 1]
DOI:10.1016/j.eja.2012.05.001URL [本文引用: 1]
Soil organic carbon (SOC) is a strong determinant of soil quality and agronomic productivity especially under harsh arid and semiarid environments of the tropics. Thus, a 20-year experiment was used to assess the impact of rainfed groundnut (Arachis hypogeae) monocropping, fertilization and manuring on soil quality, SOC sequestration, and crop yield sustainability on an Alfisol in southern India. Five treatments with 4 replications were: (1) control (no fertilizer or manure), (2) 100% recommended dose of fertilizer (RDF, 20:40:40 kg ha(-1) of N:P2O5:K2O), (3) 50% RDF + 4 Mg ha(-1) of groundnut shells (GNS), (4) 50% RDF + 4 Mg ha(-1) of farmyard manure (FYM) and (5) 5 Mg ha(-1) of FYM. The SOC concentration to 1-m depth increased from 2.3 to 3.5 g kg(-1) (52.2%) in 50% RDF+ 4 Mg ha(-1) GNS over control and mean SOC sequestration rate was 0.57 Mg C ha(-1) yr(-1). Higher mean pod yield of groundnut (Mg ha(-1)) was obtained with 50% RDF + 4 Mg ha(-1) FYM (1.03). The rate of increase in groundnut pod yield was 13 kg ha(-1) yr(-1) for every one Mg increase in profile SOC stock. A minimum of 1.12 Mg C ha(-1) yr(-1) input was needed to maintain the zero change in SOC. Hence, combined use of chemical fertilizers and organic manure is essential to enhancing SOC sequestration in monocrop regions in semi arid tropical conditions. (c) 2012 Elsevier B.V.
[本文引用: 1]
DOI:10.5194/bg-7-409-2010URL [本文引用: 3]
DOI:10.2136/sssaj1994.03615995005800020039xURL [本文引用: 1]
DOI:10.1016/S0167-1987(98)00108-1URL [本文引用: 1]
DOI:10.4141/cjss91-036URL [本文引用: 1]
URL [本文引用: 1]
Organic fertilizer application is an essential measure for improving soil organic carbon (SOC) content, promoting soil aggregate formation and improving soil structure. The objectives of this study were to investigate the influences of long-term organic and chemical fertilizer applications on the distribution and stability (in terms of mean weight diameter, MWD) of soil aggregates, aggregate formation in relation to SOC concentration and responses of SOC content of whole soils and different aggregates to cumulative C input. The experiment was initiated in 1986 and included five treatments - no fertilizer (CK), only chemical fertilizer (CF), rice straw plus chemical fertilizer (RS), low manure rate plus chemical fertilizer (M1), and high manure rate plus chemical fertilizer (M2). Soil samples (in the 0-10 cm soil layer) were collected in 2009 to determine aggregate size distribution and SOC content in bulk soil and different aggregate fractions - they are, large macro-aggregates (LM, >2 mm), small macro-aggregates (SM, 0.25-2 mm), micro-aggregates (MA, 0.25-0.053 mm) and silt plus clay (S&C, <0.053 mm) fractions. The ratios and SOC content of particulate organic matter (POM), micro-aggregates (MA-SM) and silt plus clay (S&C-SM) fractions within SM fraction were also analyzed. Compared with CK and CF treatments, combined application of rice straw or manure with chemical fertilizer significantly improved the proportions of LM and SM, and also MWD of the soil aggregates, but reduced S&C content. Changes were more evident in manure treatments (M1 and M2) than in RS treatment, but no significant difference was noted between M1 and M2. Sole chemical fertilization reduced the stability of soil aggregates. In term of SOC concentration within aggregate fractions, it was highest in LM and SM fractions, followed by S&C and then lowest in MA fraction. SOC concentration of aggregates did not increase linearly with aggregates size. Comparing the four aggregate sizes, SM fraction contributed the most to SOC sequestration in bulk soils. Within SM, MA fraction formed the key site for SOC storage. SOC contents of bulk soils, LM, SM and fractions within SM (i.e., POM, MA-SM and S&C-SM) responded positively to cumulative C input, but no apparent changes in SOC were noted for MA and S&C fractions, indicating C saturation in the two fractions. It was concluded that organic amendment (of either rice-residue or manure) promoted the formation of macro-aggregates and improved aggregate stability. However, soil organic matter was not likely the major binding agent driving soil aggregation in red paddy soils.
URL [本文引用: 1]
Organic fertilizer application is an essential measure for improving soil organic carbon (SOC) content, promoting soil aggregate formation and improving soil structure. The objectives of this study were to investigate the influences of long-term organic and chemical fertilizer applications on the distribution and stability (in terms of mean weight diameter, MWD) of soil aggregates, aggregate formation in relation to SOC concentration and responses of SOC content of whole soils and different aggregates to cumulative C input. The experiment was initiated in 1986 and included five treatments - no fertilizer (CK), only chemical fertilizer (CF), rice straw plus chemical fertilizer (RS), low manure rate plus chemical fertilizer (M1), and high manure rate plus chemical fertilizer (M2). Soil samples (in the 0-10 cm soil layer) were collected in 2009 to determine aggregate size distribution and SOC content in bulk soil and different aggregate fractions - they are, large macro-aggregates (LM, >2 mm), small macro-aggregates (SM, 0.25-2 mm), micro-aggregates (MA, 0.25-0.053 mm) and silt plus clay (S&C, <0.053 mm) fractions. The ratios and SOC content of particulate organic matter (POM), micro-aggregates (MA-SM) and silt plus clay (S&C-SM) fractions within SM fraction were also analyzed. Compared with CK and CF treatments, combined application of rice straw or manure with chemical fertilizer significantly improved the proportions of LM and SM, and also MWD of the soil aggregates, but reduced S&C content. Changes were more evident in manure treatments (M1 and M2) than in RS treatment, but no significant difference was noted between M1 and M2. Sole chemical fertilization reduced the stability of soil aggregates. In term of SOC concentration within aggregate fractions, it was highest in LM and SM fractions, followed by S&C and then lowest in MA fraction. SOC concentration of aggregates did not increase linearly with aggregates size. Comparing the four aggregate sizes, SM fraction contributed the most to SOC sequestration in bulk soils. Within SM, MA fraction formed the key site for SOC storage. SOC contents of bulk soils, LM, SM and fractions within SM (i.e., POM, MA-SM and S&C-SM) responded positively to cumulative C input, but no apparent changes in SOC were noted for MA and S&C fractions, indicating C saturation in the two fractions. It was concluded that organic amendment (of either rice-residue or manure) promoted the formation of macro-aggregates and improved aggregate stability. However, soil organic matter was not likely the major binding agent driving soil aggregation in red paddy soils.
DOI:10.3864/j.issn.0578-1752.2015.23.010URL [本文引用: 3]
【Objective】Conservation tillage is an essential measure as its function in improving the soil organic carbon (SOC) contents and the stabilization of soil aggregation. The objectives of this study are to (i) reveal the SOC sequestration under 15-year tillage systems and (ii) evaluate the contributions of different sizes of aggregates on carbon sequestration in the Loess Hilly region of China. 【Method】A long-term tillage experiment, started in 1999, was used for the study. The tillage treatments included: reduced tillage (RT), no-tillage (NT), sub-soiling with mulch (SM), and conventional tillage (CT). Recorded winter wheat yields and SOC contents at depths of 0-10 cm during the 15 years were used to estimate C input and SOC stocks, and soil samples collected in 2013 were separated into>2, 1-2, 0.25-1, 0.053-0.25, and<0.053 mm using a wet sieving method and the content of organic carbon in these aggregates were analyzed. 【Result】SOC stocks in the 0-10 cm soil layer of NT and SM were 10.9 and 10.6 t C?hm-2, and were significantly larger than RT and NT. SOC sequestration rates of NT and SM were 0.09 and 0.06 t C?hm-2?a-1. Microaggregate stored most of the organic carbon, accounting for 65% of the total organic carbon stock of the aggregate, implying that microaggregate plays an important role in SOC stock. But the organic carbon contents of microaggregates were not sensitive to tillage, indicating a C saturation in the microaggregate. Macroaggregates had higher organic carbon contents, which were about 3-8 times that of the microaggregates, and the organic carbon contents of macroaggregates were sensitive to tillage. Organic carbon stocks of macroaggregate responded positively to cumulative C input, and that means macroaggregates had a high carbon sequestration potential. SOC sequestration significantly increased with the increase of cumulative carbon inputs. To maintain the soil organic carbon stock at a stable level, the minimum annual need for C input amount was 2.4 t C?hm-2. 【Conclusion】The long-term conservation tillage (included no-tillage and sub-soiling and mulch management), is a sustainable soil carbon enhancement method for these dryland soils for the Loess Hilly region of China, it significantly promoted C sequestration and the newly organic C was mainly accumulated in the macroaggregates.
DOI:10.3864/j.issn.0578-1752.2015.23.010URL [本文引用: 3]
【Objective】Conservation tillage is an essential measure as its function in improving the soil organic carbon (SOC) contents and the stabilization of soil aggregation. The objectives of this study are to (i) reveal the SOC sequestration under 15-year tillage systems and (ii) evaluate the contributions of different sizes of aggregates on carbon sequestration in the Loess Hilly region of China. 【Method】A long-term tillage experiment, started in 1999, was used for the study. The tillage treatments included: reduced tillage (RT), no-tillage (NT), sub-soiling with mulch (SM), and conventional tillage (CT). Recorded winter wheat yields and SOC contents at depths of 0-10 cm during the 15 years were used to estimate C input and SOC stocks, and soil samples collected in 2013 were separated into>2, 1-2, 0.25-1, 0.053-0.25, and<0.053 mm using a wet sieving method and the content of organic carbon in these aggregates were analyzed. 【Result】SOC stocks in the 0-10 cm soil layer of NT and SM were 10.9 and 10.6 t C?hm-2, and were significantly larger than RT and NT. SOC sequestration rates of NT and SM were 0.09 and 0.06 t C?hm-2?a-1. Microaggregate stored most of the organic carbon, accounting for 65% of the total organic carbon stock of the aggregate, implying that microaggregate plays an important role in SOC stock. But the organic carbon contents of microaggregates were not sensitive to tillage, indicating a C saturation in the microaggregate. Macroaggregates had higher organic carbon contents, which were about 3-8 times that of the microaggregates, and the organic carbon contents of macroaggregates were sensitive to tillage. Organic carbon stocks of macroaggregate responded positively to cumulative C input, and that means macroaggregates had a high carbon sequestration potential. SOC sequestration significantly increased with the increase of cumulative carbon inputs. To maintain the soil organic carbon stock at a stable level, the minimum annual need for C input amount was 2.4 t C?hm-2. 【Conclusion】The long-term conservation tillage (included no-tillage and sub-soiling and mulch management), is a sustainable soil carbon enhancement method for these dryland soils for the Loess Hilly region of China, it significantly promoted C sequestration and the newly organic C was mainly accumulated in the macroaggregates.
DOI:10.1016/j.agrformet.2006.03.030URL [本文引用: 1]
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DOI:10.2136/sssaj1986.03615995005000030017xURL [本文引用: 1]
DOI:10.1002/2013GB004746URL [本文引用: 2]
We determined the historical change in soil organic carbon (SOC) stocks from long-term field trials that represent major soil types and climatic conditions of northern China. Soil carbon and general circulation models were validated using these field trial data sets. We then applied these models to predict future change in SOC stocks to 2100 using two net primary production (NPP) scenarios (i.e., current NPP or 1% year(-1) NPP increase). The conversion rate of plant residues to SOC was higher in single-cropping sites than in double-cropping sites. The prediction of future SOC sequestration potential indicated that these soils will be a net source of carbon dioxide (CO2) under no fertilizer inputs. Even when inorganic nutrients were applied, the additional carbon input from increased plant residues could not meet the depletion of SOC in parts of northern China. Manure or straw application could however improve the SOC sequestration potential at all sites. The SOC sequestration potential in northern China was estimated to be -4.3 to 18.2 t C ha(-1) by 2100. The effect of projected climate change on the annual rate of SOC change did not differ significantly between climate scenarios. The average annual rate of SOC change under current and increased NPP scenarios (at 850 ppm CO2) was approximately 0.136 t C ha(-1) yr(-1) in northern China. These findings highlight the need to maintain, and where possible increase, organic carbon inputs into these farming systems which are rapidly becoming inorganic fertilizer intensive.
Key Points; The RothC model is suitable for SOC simulation in upland soil in Northern China The climate change did not significantly affect annual rate of SOC change Inorganic fertilizer intensive farming need organic carbon inputs for SOC kept
DOI:10.11674/zwyf.2015.0607URL [本文引用: 1]
目的 探讨不同施肥措施土壤有机碳在不同粒级颗粒中的分配及变化情况,可揭示各级颗粒中有机碳与外源有机碳输入之间的定量关系。方法 依托南方红壤连续20年长期定位施肥试验,依据外源有机碳累积输入梯度,选择不施肥(CK)、 氮磷钾化肥配施(NPK)、 氮磷钾化肥与秸秆配施(NPKS)、 轮作条件下氮磷钾化肥与有机肥配施(NPKMR)、 氮磷钾化肥与有机肥配施(NPKM)、 单施有机肥(M)、 增量氮磷钾化肥与增量有机肥配施(1.5NPKM)7个处理,并采用物理分组方法将土壤颗粒分为砂粒(53~2000 μm)、 粗粉粒(5~53 μm)、 细粉粒(2~5 μm)和粘粒(<2 μm)4个组分。结果 与不施肥相比,长期施肥均能显著增加土壤总有机碳及各级颗粒中的有机碳的储量,其中以施用有机肥的效果最明显。不同施肥处理各级颗粒中以粘粒的有机碳储量最高,平均为16.26 t/hm2。施用有机肥和秸秆还田均能显著增加砂粒中有机碳的分配比例,降低粘粒有机碳的分配比例,而对粗粉粒和细粉粒无显著影响。土壤砂粒所占的质量百分比及其与粗粉粒、 细粉粒和粘粒的比值均与粗粉粒、 细粉粒和粘粒组分中有机碳的浓度呈显著正相关关系,表明小颗粒(粗粉粒、 细粉粒和粘粒)中有机碳的固持和富集促进了大颗粒(砂粒)的形成与稳定。各级颗粒之间,施用有机肥处理的土壤粘粒组分的固碳速率最快,为0.29~0.52 t/(hm2·a),其次为砂粒[0.30~0.40 t/(hm2·a)],而粗粉粒和细粉粒的固碳速率基本相当为 0.09~0.16 t/(hm2·a)。分析结果还表明,土壤总有机碳及各级颗粒有机碳与外源有机碳的输入呈显著正线性相关关系,其中土壤总固碳效率为10.57%,而各级颗粒之间,粘粒和砂粒组分的固碳效率(4.25%和3.60%)相当于粗粉粒和细粉粒(1.73%和1.00%)的2倍以上。结论 南方红壤各级颗粒中有机碳均没有出现饱和现象,有机碳主要在土壤粘粒和砂粒组分中富集,细颗粒中有机碳的富集会促进大粒径土壤颗粒的形成,而粘粒是土壤固碳效率最重要的矿物颗粒组成部分。表明长期配施有机肥不仅是红壤有机质提升的重要措施,也是改善红壤结构的重要途径。
DOI:10.11674/zwyf.2015.0607URL [本文引用: 1]
目的 探讨不同施肥措施土壤有机碳在不同粒级颗粒中的分配及变化情况,可揭示各级颗粒中有机碳与外源有机碳输入之间的定量关系。方法 依托南方红壤连续20年长期定位施肥试验,依据外源有机碳累积输入梯度,选择不施肥(CK)、 氮磷钾化肥配施(NPK)、 氮磷钾化肥与秸秆配施(NPKS)、 轮作条件下氮磷钾化肥与有机肥配施(NPKMR)、 氮磷钾化肥与有机肥配施(NPKM)、 单施有机肥(M)、 增量氮磷钾化肥与增量有机肥配施(1.5NPKM)7个处理,并采用物理分组方法将土壤颗粒分为砂粒(53~2000 μm)、 粗粉粒(5~53 μm)、 细粉粒(2~5 μm)和粘粒(<2 μm)4个组分。结果 与不施肥相比,长期施肥均能显著增加土壤总有机碳及各级颗粒中的有机碳的储量,其中以施用有机肥的效果最明显。不同施肥处理各级颗粒中以粘粒的有机碳储量最高,平均为16.26 t/hm2。施用有机肥和秸秆还田均能显著增加砂粒中有机碳的分配比例,降低粘粒有机碳的分配比例,而对粗粉粒和细粉粒无显著影响。土壤砂粒所占的质量百分比及其与粗粉粒、 细粉粒和粘粒的比值均与粗粉粒、 细粉粒和粘粒组分中有机碳的浓度呈显著正相关关系,表明小颗粒(粗粉粒、 细粉粒和粘粒)中有机碳的固持和富集促进了大颗粒(砂粒)的形成与稳定。各级颗粒之间,施用有机肥处理的土壤粘粒组分的固碳速率最快,为0.29~0.52 t/(hm2·a),其次为砂粒[0.30~0.40 t/(hm2·a)],而粗粉粒和细粉粒的固碳速率基本相当为 0.09~0.16 t/(hm2·a)。分析结果还表明,土壤总有机碳及各级颗粒有机碳与外源有机碳的输入呈显著正线性相关关系,其中土壤总固碳效率为10.57%,而各级颗粒之间,粘粒和砂粒组分的固碳效率(4.25%和3.60%)相当于粗粉粒和细粉粒(1.73%和1.00%)的2倍以上。结论 南方红壤各级颗粒中有机碳均没有出现饱和现象,有机碳主要在土壤粘粒和砂粒组分中富集,细颗粒中有机碳的富集会促进大粒径土壤颗粒的形成,而粘粒是土壤固碳效率最重要的矿物颗粒组成部分。表明长期配施有机肥不仅是红壤有机质提升的重要措施,也是改善红壤结构的重要途径。
DOI:10.11674/zwyf.2012.11408URL [本文引用: 2]
利用田间原位硅胶管法和自动连续在线培养监测体系（Robot 系统），分别监测了设施菜田不同施肥处理土壤剖面N2O浓度以及不同土层土壤反硝化潜势、NO和N2O产生潜势。结果表明：灌溉施肥后，传统施肥处理（CN）土壤剖面50 cm和90 cm处的N2O浓度都会出现峰值，50 cm处的N2O浓度峰值都高于90 cm处； 50 cm处的N2O变幅在2.15～50.77 μl/L 之间，90cm处的变幅在2.57～14.05 μl/L 之间；空白处理（CK）剖面N2O浓度几乎不受灌水的影响，50 cm和90 cm处的N2O浓度变幅较小，在1.43～2.75 μl/L 之间。反硝化潜势、NO和N2O产生潜势的监测结果显示，0—40 cm土层反硝化较为强烈；40—100 cm土层中由于受碳源限制，反硝化发生及强度明显滞后，添加碳源，经过48 h培养后，能够达到与表层反硝化潜势相当的程度；厌氧条件下，上层0—40 cm土壤的N2O和NO产生量远高于底层40—100 cm的。由此推测，原位监测的高N2O浓度，可能来源自上层的扩散，因而田间表层通量观测数据可能会低估N2O产生量。底层土壤有一定反硝化潜势，当施用有机肥后，底层土壤氮素反硝化损失不容忽视。
DOI:10.11674/zwyf.2012.11408URL [本文引用: 2]
利用田间原位硅胶管法和自动连续在线培养监测体系（Robot 系统），分别监测了设施菜田不同施肥处理土壤剖面N2O浓度以及不同土层土壤反硝化潜势、NO和N2O产生潜势。结果表明：灌溉施肥后，传统施肥处理（CN）土壤剖面50 cm和90 cm处的N2O浓度都会出现峰值，50 cm处的N2O浓度峰值都高于90 cm处； 50 cm处的N2O变幅在2.15～50.77 μl/L 之间，90cm处的变幅在2.57～14.05 μl/L 之间；空白处理（CK）剖面N2O浓度几乎不受灌水的影响，50 cm和90 cm处的N2O浓度变幅较小，在1.43～2.75 μl/L 之间。反硝化潜势、NO和N2O产生潜势的监测结果显示，0—40 cm土层反硝化较为强烈；40—100 cm土层中由于受碳源限制，反硝化发生及强度明显滞后，添加碳源，经过48 h培养后，能够达到与表层反硝化潜势相当的程度；厌氧条件下，上层0—40 cm土壤的N2O和NO产生量远高于底层40—100 cm的。由此推测，原位监测的高N2O浓度，可能来源自上层的扩散，因而田间表层通量观测数据可能会低估N2O产生量。底层土壤有一定反硝化潜势，当施用有机肥后，底层土壤氮素反硝化损失不容忽视。
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为了探讨不同秸秆还田模式对土壤有机碳（total organic carbon，TOC）及活性碳组分的影响，设置了秸秆不还田（CK）、秸秆直接还田（CS）、秸秆转化为食用菌基质，出蘑后菌渣还田（CMS）和秸秆过腹还田（CGS）4种还田模式。通过田间小区试验，研究了不同秸秆还田模式下，土壤有机碳及活性组分的变化规律。结果表明不同秸秆还田模式均提高了土壤有机碳含量，但不同还田模式下土壤有机碳含量差异不显著（P＞0.05），和CK相比，CS、CMS和CGS处理下，土壤有机碳质量分数分别增加9.0%、23.9%和26.7%。不同秸秆还田模式也提高了土壤活性碳组分含量。在不同秸秆还田模式下，土壤溶解性有机碳（dissolved organic carbon，DOC）含量表现为CS＞CMS＞CGS＞CK，且不同处理间差异显著（P＜0.01）。和CK相比，CS、CMS和CGS处理下，土壤DOC质量分数分别增加64.6%、29.4%和8.9%。土壤微生物量碳（microbial biomass carbon，MBC）含量表现为CMS＞CGS＞CS＞CK，且差异显著（P＜0.05）。和CK相比，CS、CMS和CGS处理下，土壤MBC质量分数分别增加28.9%、84.7%和59.3%。土壤易氧化态碳（easily oxidizable carbon，EOC）含量表现为CMS＞CS＞CGS＞CK，且差异显著（P＜0.01）。和CK相比，CS、CMS和CGS处理下，土壤EOC质量分数分别增加24.1%、55.7%、和9.3%。不同秸秆还田模式显著影响土壤活性碳组分在总有机碳中占的比例，改变土壤有机碳质量。在不同秸秆还田模式下，DOC/TOC表现为CS＞CMS＞CK＞CGS、MBC/TOC表现为CMS＞CGS＞CS＞CK、EOC/TOC表现为CMS＞CS＞CK＞CGS，且不同处理间均差异显著（P＜0.01）。从提高土壤质量角度，推荐秸秆-菌渣还田模式，在该模式下，土壤MBC/TOC和EOC/TOC均最大，土壤碳素有效性高、易于被微生物利用，有利于作物生长。从提高土壤固碳角度，推荐秸秆过腹还田模式，在该模式下，土壤DOC/TOC最小，且土壤有机碳含量最高，有利于碳的固定和保存。该研究结果可为秸秆合理高效利用、改善农业土壤碳库质量提供参考。
URL [本文引用: 1]
为了探讨不同秸秆还田模式对土壤有机碳（total organic carbon，TOC）及活性碳组分的影响，设置了秸秆不还田（CK）、秸秆直接还田（CS）、秸秆转化为食用菌基质，出蘑后菌渣还田（CMS）和秸秆过腹还田（CGS）4种还田模式。通过田间小区试验，研究了不同秸秆还田模式下，土壤有机碳及活性组分的变化规律。结果表明不同秸秆还田模式均提高了土壤有机碳含量，但不同还田模式下土壤有机碳含量差异不显著（P＞0.05），和CK相比，CS、CMS和CGS处理下，土壤有机碳质量分数分别增加9.0%、23.9%和26.7%。不同秸秆还田模式也提高了土壤活性碳组分含量。在不同秸秆还田模式下，土壤溶解性有机碳（dissolved organic carbon，DOC）含量表现为CS＞CMS＞CGS＞CK，且不同处理间差异显著（P＜0.01）。和CK相比，CS、CMS和CGS处理下，土壤DOC质量分数分别增加64.6%、29.4%和8.9%。土壤微生物量碳（microbial biomass carbon，MBC）含量表现为CMS＞CGS＞CS＞CK，且差异显著（P＜0.05）。和CK相比，CS、CMS和CGS处理下，土壤MBC质量分数分别增加28.9%、84.7%和59.3%。土壤易氧化态碳（easily oxidizable carbon，EOC）含量表现为CMS＞CS＞CGS＞CK，且差异显著（P＜0.01）。和CK相比，CS、CMS和CGS处理下，土壤EOC质量分数分别增加24.1%、55.7%、和9.3%。不同秸秆还田模式显著影响土壤活性碳组分在总有机碳中占的比例，改变土壤有机碳质量。在不同秸秆还田模式下，DOC/TOC表现为CS＞CMS＞CK＞CGS、MBC/TOC表现为CMS＞CGS＞CS＞CK、EOC/TOC表现为CMS＞CS＞CK＞CGS，且不同处理间均差异显著（P＜0.01）。从提高土壤质量角度，推荐秸秆-菌渣还田模式，在该模式下，土壤MBC/TOC和EOC/TOC均最大，土壤碳素有效性高、易于被微生物利用，有利于作物生长。从提高土壤固碳角度，推荐秸秆过腹还田模式，在该模式下，土壤DOC/TOC最小，且土壤有机碳含量最高，有利于碳的固定和保存。该研究结果可为秸秆合理高效利用、改善农业土壤碳库质量提供参考。
URL [本文引用: 1]
Most studies on straw decomposition in soil have been conducted with straw additions in the range of 0 100 g of straw per kilogram of soil. Actually, straw could be unevenly incorporated into soil resulting in very high local straw addition amounts, higher than 100 g per kilogram of soil under field conditions. There have been contradictory research results about straw decomposition in soil with straw addition of less than 100 g per kilogram of soil. In this study, the effects of straw addition amounts on organic carbon decomposition, composition and liability of yellow fluvo-aquic soils and lime concretion black soils were studied to develop a theoretical basis for straw decomposition in soils, and improvements in soil carbon cycle and soil fertility for high-harvest cultivation. After one year of indoor soil incubation with straw addition amounts of 0 400 g per kilogram of soil at (35±1) ℃ and 80% 95% field water capacity, the decomposition rates and humification coefficients of soil organic matter, soil C/N ratio, active soil organic carbon (AOC), inactive organic carbon (IOC), total organic carbon (TOC), AOC/TOC ratio and carbon lability (soil AOC/IOC ratio, L%) were determined. The results showed that humification coefficients of total soil organic matter were 20% 35%. With increasing straw dose, humification coefficient decreased while organic matter decomposition rate, AOC, IOC, TOC and L increased. These variables were significantly (P< 0.01) and positively correlated with straw addition amount. Also while a significant (P< 0.01) and positive correlation was noted between AOC and TOC, the correlation between the humification coefficient and L was significant (P< 0.01) but negative. The contents of clay particles smaller than 0.002 mm in yellow fluvo-aquic soils and lime concretion black soils were 33% and 41%, respectively. Straw was more likely to break down in yellow fluvo-aquic soils than in lime concretion black soils. Higher clay content in lime concretion black soils highly favored soil carbon storage. After one year of indoor incubation, soil AOC/TOC ratio and L in yellow fluvo-aquic soils were on average 7.6 and 12.3 percentage points higher than those in lime concre-tion black soils, respectively. Humification coefficient and soil C/N ratio in lime concretion black soils were on average 3.2 and 2.3 percentage points higher than those in yellow fluvo-aquic soils, respectively. In conclusion, the higher the soil carbon lability, the more beneficial was to increasing decomposition rate and reducing humification coefficient of soil organic matter. Then the higher the soil clay content, the lower the decomposition rate and the higher the humificatin coefficient of soil organic matter. This was in accordance with the results of previous studies conducted with straw addition amount less than 100 g per kilogram of soil. There was the need for further studies under field conditions under different soil types and different straw addition amounts.
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Most studies on straw decomposition in soil have been conducted with straw additions in the range of 0 100 g of straw per kilogram of soil. Actually, straw could be unevenly incorporated into soil resulting in very high local straw addition amounts, higher than 100 g per kilogram of soil under field conditions. There have been contradictory research results about straw decomposition in soil with straw addition of less than 100 g per kilogram of soil. In this study, the effects of straw addition amounts on organic carbon decomposition, composition and liability of yellow fluvo-aquic soils and lime concretion black soils were studied to develop a theoretical basis for straw decomposition in soils, and improvements in soil carbon cycle and soil fertility for high-harvest cultivation. After one year of indoor soil incubation with straw addition amounts of 0 400 g per kilogram of soil at (35±1) ℃ and 80% 95% field water capacity, the decomposition rates and humification coefficients of soil organic matter, soil C/N ratio, active soil organic carbon (AOC), inactive organic carbon (IOC), total organic carbon (TOC), AOC/TOC ratio and carbon lability (soil AOC/IOC ratio, L%) were determined. The results showed that humification coefficients of total soil organic matter were 20% 35%. With increasing straw dose, humification coefficient decreased while organic matter decomposition rate, AOC, IOC, TOC and L increased. These variables were significantly (P< 0.01) and positively correlated with straw addition amount. Also while a significant (P< 0.01) and positive correlation was noted between AOC and TOC, the correlation between the humification coefficient and L was significant (P< 0.01) but negative. The contents of clay particles smaller than 0.002 mm in yellow fluvo-aquic soils and lime concretion black soils were 33% and 41%, respectively. Straw was more likely to break down in yellow fluvo-aquic soils than in lime concretion black soils. Higher clay content in lime concretion black soils highly favored soil carbon storage. After one year of indoor incubation, soil AOC/TOC ratio and L in yellow fluvo-aquic soils were on average 7.6 and 12.3 percentage points higher than those in lime concre-tion black soils, respectively. Humification coefficient and soil C/N ratio in lime concretion black soils were on average 3.2 and 2.3 percentage points higher than those in yellow fluvo-aquic soils, respectively. In conclusion, the higher the soil carbon lability, the more beneficial was to increasing decomposition rate and reducing humification coefficient of soil organic matter. Then the higher the soil clay content, the lower the decomposition rate and the higher the humificatin coefficient of soil organic matter. This was in accordance with the results of previous studies conducted with straw addition amount less than 100 g per kilogram of soil. There was the need for further studies under field conditions under different soil types and different straw addition amounts.
DOI:10.1016/j.still.2011.01.007URL [本文引用: 1]
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DOI:10.1023/A:1016125726789URL [本文引用: 1]
The relationship between soil structure and the ability of soil to stabilize soil organic matter (SOM) is a key element in soil C dynamics that has either been overlooked or treated in a cursory fashion when developing SOM models. The purpose of this paper is to review current knowledge of SOM dynamics within the framework of a newly proposed soil C saturation concept. Initially, we distinguish SOM that is protected against decomposition by various mechanisms from that which is not protected from decomposition. Methods of quantification and characteristics of three SOM pools defined as protected are discussed. Soil organic matter can be: (1) physically stabilized, or protected from decomposition, through microaggregation, or (2) intimate association with silt and clay particles, and (3) can be biochemically stabilized through the formation of recalcitrant SOM compounds. In addition to behavior of each SOM pool, we discuss implications of changes in land management on processes by which SOM compounds undergo protection and release. The characteristics and responses to changes in land use or land management are described for the light fraction (LF) and particulate organic matter (POM). We defined the LF and POM not occluded within microaggregates (53–250
m sized aggregates as unprotected. Our conclusions are illustrated in a new conceptual SOM model that differs from most SOM models in that the model state variables are measurable SOM pools. We suggest that physicochemical characteristics inherent to soils define the maximum protective capacity of these pools, which limits increases in SOM (i.e. C sequestration) with increased organic residue inputs.DOI:10.4141/S06-015URL [本文引用: 1]
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DOI:10.1023/A:1009794514742URL [本文引用: 1]
URL [本文引用: 1]
以国家褐潮土16a的长期肥料试验为平台（北京昌平），研究长期不同施肥对耕层土壤水稳定性团聚体及其有机碳的影响。主要研究结果：与耕种农田土壤相比，长期撂荒（CK0）可以提高水稳定性大团聚体的含量及其有机碳含量和储量。而农田耕作后，破坏了水稳性大团聚体，相应地增加水稳性微团聚体的含量。与长期不施肥种植作物（CK）相比，长期施氮磷钾肥（NPK）、氮磷钾配施有机肥（NPKM）和氮磷钾秸秆还田（NPKS）处理对水稳性团聚体数量分布和平均重量直径（MWD）有显著影响，其中对>2mm和0.25-2mm水稳性大团聚体的促进作用最明显，说明施肥处理增加的新碳主要向0.25-2mm和>2mm团聚体富集。在不同水平水稳性团聚体中，>2mm和0.25-2mm两个级别的水稳性大团聚体有机碳的含量显著高于0.053-0.25mm和<0.053mm水稳性微团聚体。化肥与有机肥配施（NPKM）处理可提高水稳性大团聚体含量，改善土壤团聚体的结构。长期小麦-玉米→小麦-大豆复种轮作并施氮磷钾化肥的处理（NPKF）各级团聚体中有机碳的含量高于长期小麦-玉米轮作并施氮磷钾化肥的处理（NPK）。
URL [本文引用: 1]
以国家褐潮土16a的长期肥料试验为平台（北京昌平），研究长期不同施肥对耕层土壤水稳定性团聚体及其有机碳的影响。主要研究结果：与耕种农田土壤相比，长期撂荒（CK0）可以提高水稳定性大团聚体的含量及其有机碳含量和储量。而农田耕作后，破坏了水稳性大团聚体，相应地增加水稳性微团聚体的含量。与长期不施肥种植作物（CK）相比，长期施氮磷钾肥（NPK）、氮磷钾配施有机肥（NPKM）和氮磷钾秸秆还田（NPKS）处理对水稳性团聚体数量分布和平均重量直径（MWD）有显著影响，其中对>2mm和0.25-2mm水稳性大团聚体的促进作用最明显，说明施肥处理增加的新碳主要向0.25-2mm和>2mm团聚体富集。在不同水平水稳性团聚体中，>2mm和0.25-2mm两个级别的水稳性大团聚体有机碳的含量显著高于0.053-0.25mm和<0.053mm水稳性微团聚体。化肥与有机肥配施（NPKM）处理可提高水稳性大团聚体含量，改善土壤团聚体的结构。长期小麦-玉米→小麦-大豆复种轮作并施氮磷钾化肥的处理（NPKF）各级团聚体中有机碳的含量高于长期小麦-玉米轮作并施氮磷钾化肥的处理（NPK）。
DOI:10.1016/S0038-0717(00)00179-6URL [本文引用: 2]
DOI:10.1111/gcb.2007.13.issue-6URL [本文引用: 1]
DOI:10.11674/zwyf.2015.0212URL [本文引用: 1]
【目的】团聚体形成被认为是土壤固碳的最重要机制。本文以河南豫西地区长期耕作试验为研究对象，研究了长期保护性耕作对土壤团聚体性质及土壤有机碳(SOC)含量的影响，为探讨土壤固碳机理，优化黄土高原坡耕地区农田耕作管理措施，实现土壤固碳减排、培肥土壤提供理论依据。【方法】长期耕作试验开始于1999年，试验处理有免耕覆盖(NT)、深松覆盖(SM)和翻耕(CT)。利用湿筛法筛分第3年(2002年)和第13年(2011年)0—10 cm和10—20 cm土层中，＞2000、250
DOI:10.11674/zwyf.2015.0212URL [本文引用: 1]
【目的】团聚体形成被认为是土壤固碳的最重要机制。本文以河南豫西地区长期耕作试验为研究对象，研究了长期保护性耕作对土壤团聚体性质及土壤有机碳(SOC)含量的影响，为探讨土壤固碳机理，优化黄土高原坡耕地区农田耕作管理措施，实现土壤固碳减排、培肥土壤提供理论依据。【方法】长期耕作试验开始于1999年，试验处理有免耕覆盖(NT)、深松覆盖(SM)和翻耕(CT)。利用湿筛法筛分第3年(2002年)和第13年(2011年)0—10 cm和10—20 cm土层中，＞2000、250
