,1,2, 张云舒2, 徐万里2, 马海刚2, 胡克林,1Effects of Long-Term Cultivation on Contents of Organic Carbon and Total Nitrogen in Soil Particulate Fraction in Oasis Farmland of Xinjiang
TANG GuangMu,1,2, ZHANG YunShu2, XU WanLi2, MA HaiGang2, HU KeLin,1通讯作者:
责任编辑: 李云霞
收稿日期:2020-04-2接受日期:2020-05-8网络出版日期:2020-12-16
| 基金资助: |
Received:2020-04-2Accepted:2020-05-8Online:2020-12-16
作者简介 About authors
唐光木,E-mail：
摘要
关键词：
Abstract
Keywords：
PDF (556KB)元数据多维度评价相关文章导出EndNote|Ris|Bibtex收藏本文
本文引用格式
唐光木, 张云舒, 徐万里, 马海刚, 胡克林. 长期耕作对新疆绿洲农田土壤颗粒中有机碳和全氮含量的影响[J]. 中国农业科学, 2020, 53(24): 5039-5049 doi:10.3864/j.issn.0578-1752.2020.24.007
TANG GuangMu, ZHANG YunShu, XU WanLi, MA HaiGang, HU KeLin.
开放科学（资源服务）标识码（OSID）：
0 引言
【研究意义】土壤碳、氮是陆地生态系统最重要的组成部分,在全球碳氮循环中起主导作用[1]。同时土壤碳、氮还是反映土壤质量和健康的重要指标,直接影响土壤肥力和作物产量的高低,增加土壤碳、氮对减缓温室效应、增加作物产量及促进农业可持续发展具有重要的意义[2]。土壤有机碳、全氮是由活性、功能、周转速率不同的组分构成的复合体,其总量变化难以准确反映土壤碳、氮对环境变化的响应[3],而土壤有机碳、全氮组分及碳氮比值对农业措施改变的敏感性更高,有利于揭示农田管理措施对土壤碳、氮的影响机制[4],已成为当前认知土壤碳、氮累积变化过程与循环的研究热点。【前人研究进展】根据土壤颗粒大小将土壤颗粒分为砂粒（>50 μm）、粉粒（2—50 μm）和黏粒（<2 μm）[5],砂粒中有机碳、全氮一般被认为是主要活性有机碳氮组分,黏粒和粉粒中有机碳、全氮为非活性碳氮组分[6]。砂粒中有机碳、全氮组分对耕作、施肥措施的响应往往比总有机碳、氮更敏感,更能预警或者较早反映土壤碳、氮指标的变化[7],土壤粉粒和黏粒组分中有机碳和全氮决定着土壤碳、氮的固存[8]。土壤碳氮比值是评价土壤有机物分解程度的一个重要指标,是土壤有机碳、全氮矿化能力的重要标志[9],该比值越高,有机物的分解程度越低,有机碳趋于积累[10],反之土壤有机碳的增加速度低于土壤全氮,会加快微生物对于土壤有机碳的分解和氮的矿化速率,不利于土壤有机碳、全氮的固存[11]。在农田生态系统中,土壤耕作、施肥等农田管理措施被认为是加速土壤有机碳矿化分解、氮素周转、影响土壤化学和生物学性质的重要因素,其强度与频率是影响土壤有机碳、全氮周转的关键[12]。BURNS等[13]认为耕作、田间管理措施和土壤外源碳氮添加可引发酶类产生不同的响应,通过改变底物有效性及微环境条件影响微生物活性[14],进而影响土壤碳、氮循环生态过程[15]。徐梦等[16]认为自然森林和草地土壤转变为农田,长期耕作导致粗颗粒有机碳数量和土壤不稳定颗粒组分碳氮比值低于自然森林和草地土壤,农业耕作显著加速了不稳定颗粒有机碳的周转,减少了稳定性有机碳组分的形成。佟小刚等[17]和WU等[18]研究发现长期施用有机肥显著增加土壤颗粒中有机碳、全氮组分的含量和黏粒中有机碳、全氮含量;陈洁等[19]等在湖北稻麦轮作地区研究指出,长期有机无机肥配施处理显著促进了土壤碳、氮的积累,尤其是颗粒中有机碳、全氮。但也有研究指出施肥对不同组分中有机碳、全氮的影响作用并不一致。SCHULTEN等[20]认为,长期施化肥,特别是单施氮肥,对各颗粒中有机碳含量影响较小。【本研究切入点】新疆位于中国西部内陆干旱荒漠区,屯垦戍边以来,耕作方式与时间、施肥方式与水平、土壤性质以及气候条件等因素均影响土壤有机碳、全氮数量和质量变化,以及土壤有机碳、全氮的周转和储量。然而,对于耕作导致的土壤有机碳、全氮的差异性,特别是长期耕作对不同粒径颗粒中有机碳、全氮组分的影响作用,亟需进行深入分析。【拟解决的关键问题】本研究选择新疆干旱荒漠区南北疆不同耕作年限的棉田土壤为研究对象,利用基于土壤颗粒粒径物理分组法将土壤分为不同颗粒组分,研究耕作对不同颗粒组分中有机碳、全氮的变化规律,揭示长期耕作对土壤碳氮循环的影响机制,为我国区域农田土壤碳氮变化规律研究和农业土壤固碳潜力与生产力长期稳定机制提供参考。1 材料与方法
1.1 样品采集
选择冲积平原区成土条件一致、灌溉、耕作方式和栽培模式相近的3个典型绿洲区：昌吉回族自治州兰州湾镇（86°05′—86°06′ E,44°29′—44°30′ N）、巴音郭楞蒙古自治州普惠农场（85°50′—85°52′ E,41°24′—41°26′ N）以及新疆生产建设兵团第二师31团（86°54′—86°59′ E,40°50′—40°54′ N）,研究区自然植被以荒漠和荒漠草原植被为主,兰州湾镇主要有芨芨草、骆驼刺、红柳等,普惠农场和31团主要是红柳、芦苇等植物。3个绿洲区种植作物均为棉花,采用膜下滴灌栽培模式和秋深翻、秸秆还田的耕作方式,土壤类型分别为灰漠土、潮土和灌淤土,土壤基本理化性质见表1。以不同耕作年限（5、10、15和20 a）的农田作为采样点,以相邻未耕作土壤作为对照,每个采样点选择3—5块样地进行采样,每块样地采集耕层（0—30 cm）土壤样品5—7个,采用多点混合四分法留取土壤样品1.00 kg左右,带回实验室,去除肉眼能看到的有机残体,自然风干后,研磨过2 mm和0.25 mm筛,用于土壤颗粒组分分离和土壤理化性质测定。Table 1
表1
表1土壤基本理化性质
Table 1
| 采样点 Sampling site | pH | 容重 Bulk density (g·cm-3) | 碱解氮 Available N (mg·kg-1) | 速效磷 Available P (mg·kg-1) | 速效钾 Available K (mg·kg-1) | 电导率 EC (mS·cm-1) | 阳离子交换量 CEC (cmol·kg-1) |
|---|---|---|---|---|---|---|---|
| 兰州湾 Lanzhouwan | 8.18±0.19 | 1.41±0.18 | 53.33±45.97 | 14.07±21.43 | 380.00±144.00 | 1.66±0.69 | 11.31±9.11 |
| 31团 31 corps | 8.03±0.09 | 1.41±0.19 | 50.25±6.32 | 28.72±8.21 | 135.00±9.40 | 0.58±0.09 | 10.56±1.26 |
| 普惠农场 Puhui farm | 7.92±0.13 | 1.47±0.13 | 47.35±10.32 | 60.09±28.17 | 128.40±23.84 | 1.21±0.51 | 9.37±1.86 |
新窗口打开|下载CSV
1.2 分析方法
上述过2 mm筛的土壤样品,采用武天云等[5]的Ander-son和Tiessen改进法进行不同颗粒组分的分离,将土壤样品分离出不同粒径（>50 μm,2—50 μm,<2 μm）土壤颗粒组分,分离得到的不同粒径的土壤颗粒组分先在60℃的水浴锅上蒸干,再在60℃的烘箱中烘干12 h,冷却,称重。将烘干的不同粒径土壤颗粒研磨过0.25 mm筛,用于测定不同颗粒组分中有机碳和全氮含量。土壤有机碳、全氮以及不同颗粒组分中有机碳、全氮含量均按照《土壤农业化学常规分析方法》中方法测定[21]。
1.3 数据处理
采用WPS 2016和SAS8.0统计分析软件进行试验数据分析和绘图,多重比较用LSD法。2 结果
2.1 不同耕作年限土壤有机碳和全氮含量变化
与未耕作土壤相比,耕作5 a土壤有机碳含量增加迅速,兰州湾镇、普惠农场和31团分别提高了76.4%、286.2%和145.6%（图1）,耕作5 a后,土壤有机碳含量增加趋势变缓。与耕作5—15 a相比,耕作20 a后兰州湾镇、普惠农场和31团的土壤有机碳含量分别增加了10.5%、20.1%和43.5%,年均增速为0.04、0.10和0.16 g·kg-1。耕作0—20 a对兰州湾土壤全氮含量的影响相对较小,年均增加0.02 g·kg-1。耕作初期（0—5 a）31团和普惠农场对其全氮含量的影响较大,年均分别增加了0.086和0.090 g·kg-1,耕作5 a后增速逐渐趋于平缓。图1
新窗口打开|下载原图ZIP|生成PPT图1不同耕作年限土壤有机碳和全氮含量的变化
Fig. 1Change of the content of SOC and TN in different tillage years
2.2 不同耕作年限土壤颗粒组分中有机碳和全氮含量及其占比
不同颗粒中有机碳、全氮是土壤有机碳、全氮的重要组成部分,直接反映了土壤有机碳、全氮的有效性,对环境或管理措施的响应极其敏感。从表2中可知,各组分中砂粒中有机碳、全氮含量最小,在0.32—2.05 g·kg-1和0.02—0.51 g·kg-1之间,但随着耕作时间的延长,砂粒中有机碳、全氮含量呈现不同的变化趋势。耕作0—5 a间,砂粒中有机碳含量快速增加,兰州湾、31团和普惠农场分别年均增加0.14、0.20和 0.22 g·kg-1,耕作10—15 a间砂粒中有机碳含量达到峰值,随后出现下降的趋势。砂粒中全氮含量则呈现逐步增加趋势,与未耕作土壤相比,耕作20 a后兰州湾、普惠农场和31团砂粒中全氮含量分别增加了0.24、0.4和0.29 g·kg-1。Table 2
表2
表2不同耕作年限土壤颗粒组分中有机碳和全氮含量
Table 2
| 采样区 Sampling site | 耕作年限 Tillage year （a） | 砂粒 Sand（>50 μm） | 粉粒 Silt（2-50 μm） | 黏粒 Clay（<2 μm） | |||
|---|---|---|---|---|---|---|---|
| 有机碳 Organic carbon (g·kg-1) | 全氮 Total nitrogen (g·kg-1) | 有机碳 Organic carbon (g·kg-1) | 全氮 Total nitrogen (g·kg-1) | 有机碳 Organic carbon (g·kg-1) | 全氮 Total nitrogen (g·kg-1) | ||
| 兰州湾 Lanzhouwan | 0 | 0.40±0.12c | 0.07±0.00d | 1.57±0.50c | 0.56±0.05ab | 1.65±0.20d | 0.37±0.01d |
| 5 | 1.10±0.57b | 0.09±0.00d | 2.95±0.59b | 0.52±0.03b | 2.34±0.13bc | 0.56±0.07ab | |
| 10 | 1.25±0.74a | 0.16±0.02c | 3.03±0.35b | 0.49±0.04b | 2.48±0.47ab | 0.62±0.05bc | |
| 15 | 1.02±0.38b | 0.24±0.01b | 3.11±0.86b | 0.61±0.07ab | 2.88±0.22a | 0.48±0.05a | |
| 20 | 1.03±0.58b | 0.31±0.07a | 3.96±0.49a | 0.69±0.10a | 2.07±0.21c | 0.40±0.04cd | |
| 31团 31 corps | 0 | 0.32±0.18d | 0.02±0.00d | 1.02±0.70d | 0.53±0.02a | 0.57±0.20c | 0.16±0.01c |
| 5 | 1.34±0.34b | 0.14±0.01c | 3.39±0.49c | 0.42±0.07a | 2.61±0.69b | 0.59±0.11ab | |
| 10 | 1.52±0.78a | 0.21±0.03b | 3.72±0.91b | 0.38±0.01a | 2.54±0.37b | 0.65±0.09a | |
| 15 | 1.31±0.50bc | 0.25±0.01ab | 4.15±0.58a | 0.47±0.06a | 2.77±0.18b | 0.54±0.03b | |
| 20 | 1.21±0.96c | 0.31±0.05a | 4.41±0.47a | 0.54±0.03a | 3.21±0.32a | 0.49±0.07b | |
| 普惠农场 Puhui farm | 0 | 0.42±0.44c | 0.04±0.00d | 1.04±0.17d | 0.32±0.00b | 0.77±0.29c | 0.23±0.01d |
| 5 | 1.51±0.96b | 0.19±0.01c | 2.39±0.51c | 0.41±0.05b | 1.59±0.29b | 0.39±0.04b | |
| 10 | 1.72±0.11ab | 0.36±0.03b | 2.41±0.50c | 0.43±0.03b | 1.75±0.24ab | 0.44±0.03a | |
| 15 | 2.05±0.79a | 0.42±0.02ab | 3.41±0.70b | 0.58±0.09a | 2.00±0.23ab | 0.36±0.01c | |
| 20 | 1.98±0.17a | 0.51±0.06a | 3.76±0.76a | 0.64±0.11a | 2.13±0.47a | 0.25±0.00d | |
新窗口打开|下载CSV
粉粒有机碳是土壤颗粒组分中固持有机碳最主要碳库,其含量在1.02—4.41 g·kg-1之间,是砂粒中有机碳含量的2—3倍,相比未耕作土壤,兰州湾、31团和普惠农场土壤粉粒中有机碳含量随耕作时间的延长而增加,耕作20 a分别显著增加152.2%、332.4%和261.5%。相比未耕作土壤,耕作0—10 a间兰州湾和31团土壤粉粒中全氮含量呈现下降趋势,10 a后开始增加;普惠农场粉粒中全氮含量则随耕作时间呈持续增加趋势,耕作20 a显著增加一倍,耕作15—20 a后,粉粒中全氮含量成为土壤全氮含量最大的组分。
黏粒中有机碳含量介于砂粒和粉粒中有机碳含量之间,与耕作年限关系不显著,但随耕作年限延长而增加,相比未耕作土壤,耕作20 a后,兰州湾、31团和普惠农场黏粒中有机碳分别显著增加25.5%、463.2%和176.6%;黏粒中全氮含量呈倒“V”字形变化,相比未耕作土壤,耕作0—10 a间,黏粒中全氮含量快速增加,兰州湾、31团和普惠农场分别提高了67.6%、306.3%和91.3%,耕作10 a后开始下降,耕作20 a相比耕作10 a分别降低了35.5%、24.6%和34.1%,除31团外,基本接近于未耕作土壤黏粒中全氮含量。
耕作改变了不同颗粒中有机碳、全氮含量在土壤有机碳和全氮含量中的分配比例（图2）,粉粒中有机碳含量占比最大,在43.3%—56.1%之间,砂粒中有机碳含量占比最小,在11.0%—29.3%之间,黏粒中有机碳含量占比为26.9%—41.1%,粉粒和黏粒中有机碳含量成为土壤有机碳分配主体,增强了对土壤有机碳的固持和保护。不同颗粒组分中全氮分配比例中,粉粒中全氮含量占比最大,为30.2%—72.2%,砂粒中全氮含量占比最小,为2.4%—35.9%。砂粒中有机碳含量占比总体表现为耕作0—10 a 间逐渐增加,在10—20 a间呈降低趋势,砂粒中全氮含量占比则随耕作时间表现出递增趋势。耕作20 a间,兰州湾、31团和普惠农场,砂粒中全氮占比分别从6.4%、2.4%和6.9%增加到21.2%、22.2%和35.9%,分别增加了14.8%、19.8%和29.0%。由此可见,耕作改变了砂粒中有机碳、全氮含量在土壤有机碳和全氮含量中的分配比例,增加了对土壤有机碳、全氮的贡献程度,同时砂粒中全氮含量占比随耕作时间的延长呈增加趋势。
图2
新窗口打开|下载原图ZIP|生成PPT图2不同耕作年限土壤有机碳和全氮在不同颗粒组分中的分配
Fig. 2Distribution of SOC and TN in different particle fractions in different tillage years
土壤有机碳、全氮始终处于动态变化之中,土壤有机碳、全氮与不同颗粒组分中有机碳、全氮之间的耦合关系更能全面反映土壤有机碳、全氮的转化变异特征[22]。从图3可以看出,土壤有机碳、全氮含量与不同颗粒组分中有机碳、全氮含量呈显著正相关关系,但兰州湾和31团全氮含量与黏粒中全氮含量以及普惠农场全氮含量与粉粒中全氮含量之间差异不显著,说明不同颗粒组分中有机碳和砂粒中全氮含量随土壤有机碳、全氮含量的增加而增加。
图3
新窗口打开|下载原图ZIP|生成PPT图3土壤有机碳或全氮与不同颗粒组分中碳或氮的关系
Fig. 3Relationship between SOC or TN and carbon or nitrogen in different particle fractions
2.3 不同耕作年限土壤不同颗粒组分碳氮比变化
土壤有机碳和全氮比值（C/N）是土壤质量的敏感指标,该比值的改变可引起微生物活性的变化进而影响土壤质量和土壤碳氮循环[23]。土壤中有机碳的分解受土壤和微生物碳氮平衡的影响,碳氮比值在很大程度上影响其分解速率。耕作提高了土壤碳氮比,耕作0—5 a间,土壤中碳氮比迅速提高40.3%— 142.9%（表3）,5 a后,碳氮比值变化不明显,但碳氮比仍高于未耕作土壤,说明微生物活性降低,减缓有机碳和有机氮分解矿化,土壤固碳能力提高。除兰州湾外,耕作5 a后,砂粒中有机碳氮比迅速降低,31团和普惠农场显著降低了48.1%和20.4%;粉粒中碳氮比快速增加,兰州湾、31团和普惠农场分别显著提高了102.8%、320.6%和78.4%。同时,耕作也改变了土壤各颗粒组分中碳氮比的分配比例,表现为耕作0—5a间,砂粒中的碳氮比高于粉粒和黏粒中的碳氮比,5 a后粉粒中碳氮比最高。Table 3
表3
表3不同耕作年限土壤及其颗粒组分碳氮比
Table 3
| 采样区 Sampling site | 耕作年限 Tillage year （a） | 土壤碳氮比 C/N | 颗粒组分碳氮比C/N in particle fractions | ||
|---|---|---|---|---|---|
| 砂粒Sand (>50 μm) | 粉粒Silt (2-50 μm) | 黏粒Clay (<2 μm) | |||
| 兰州湾 Lanzhouwan | 0 | 3.55±0.97b | 6.14±0.12bc | 2.82±0.55b | 4.41±0.21bc |
| 5 | 5.46±0.70a | 12.22±0.57a | 5.72±0.62a | 4.16±0.20c | |
| 10 | 5.24±0.78a | 7.81±0.76b | 6.16±0.39a | 4.00±0.52c | |
| 15 | 5.23±0.86a | 4.32±0.39cd | 5.08±0.93a | 6.00±0.27a | |
| 20 | 4.77±0.95ab | 3.28±0.65d | 5.71±0.59a | 5.16±0.25ab | |
| 31团 31 corps | 0 | 2.61±0.36b | 18.16±0.18a | 1.94±0.72c | 3.46±0.21d |
| 5 | 6.34±0.62a | 9.43±0.35b | 8.16±0.56b | 4.46±0.80c | |
| 10 | 6.14±0.73a | 7.12±0.81c | 9.71±0.92ab | 3.88±0.46cd | |
| 15 | 6.10±0.40a | 5.23±0.51cd | 8.77±0.64ab | 5.17±0.21b | |
| 20 | 6.31±0.38a | 3.89±1.01d | 8.12±0.50b | 6.53±0.35a | |
| 普惠农场 Puhui farm | 0 | 3.72±0.48c | 10.14±0.44a | 3.28±0.17b | 3.38±0.30d |
| 5 | 5.22±0.32ab | 8.07±0.97b | 5.85±0.56a | 4.07±0.33c | |
| 10 | 4.78±0.46b | 4.78±0.14c | 5.60±0.53a | 3.96±0.27c | |
| 15 | 5.43±0.58ab | 4.88±0.81c | 5.86±0.79a | 5.59±0.24b | |
| 20 | 5.54±0.73a | 3.88±0.23b | 5.84±0.87a | 8.41±0.47a | |
新窗口打开|下载CSV
3 讨论
3.1 长期耕作对土壤有机碳和全氮含量的影响
在新疆干旱荒漠条件下,土壤有机碳初始值很低的土壤耕作后,土壤有机碳呈现增加趋势,增加了绿洲生态系统土壤有机碳的固定,从而在我国陆地碳循环过程中增加了有机碳的储量。本文的研究结果与草地[24]、林地开垦耕作[25]以及东北黑土地区耕作[26]后有机碳下降有明显的区别,这可能由地理位置、气候条件及作物种类的差异,以及未耕作土壤有机碳初始值不同引起的。全氮表现出与总有机碳相似的规律,随耕作年限的延长呈递增趋势,说明土壤有机碳和全氮的变化趋势具有一致性[27]。土壤有机碳、全氮是评价农田土壤质量和肥力以及农业生产可持续性的重要因子,但其库容大、变异小,不能快速反映土壤有机碳水平和供氮能力变化[20]。基于土壤物理分组的有机碳、全氮组分,可反映土壤有机碳、全氮的抗氧化程度,利用的难易程度以及非均匀分布的性质或功能,对耕作和农田管理反映较为敏感[28],其中颗粒有机碳、全氮组分容易被微生物利用分解[29]和作物吸收利用,一定程度上能够提高土壤养分的有效性。研究区域不同,农田管理措施的差异,对不同有机碳、全氮组分的影响作用并不一致[16-19,30]。本研究表明,在干旱荒漠区,长期耕作提高了砂粒和粉粒中有机碳、全氮含量,并随耕作时间的延长而增加,这与于维水等[31]的研究结果一致,究其原因一方面可能是由于干旱荒漠区未耕作土壤有机碳、全氮含量相对较低,长期耕作增加了土壤有机物的输入,特别是耕作初期增加了土壤微生物和动物的活性[32],耕作20 a,兰州湾、31团和普惠农场土壤脲酶活性、蔗糖酶活性显著增强（附表1）,相比未耕作土壤分别显著提高了85.4%、60.4%、131.7%和101.5%、79.3%和116.8%,同时植物残体和根系分泌物增加,从而增加了土壤砂粒中有机碳、全氮组分含量。另一方面,长期耕作促进土壤团聚体的形成[33]和土壤砂粒含量的增加[34],使更多的有机碳、全氮被土壤团聚体固持,耕作20 a,兰州湾、31团和普惠农场>53 μm的团聚体含量显著增加（附表1）,相比未耕作土壤分别显著增加了46.5%、81.2%和87.3%,从而增加砂粒中有机碳、全氮的含量[35]。长期耕作也改变了不同颗粒中有机碳、全氮组分的分配比例,这是可能是有机碳、全氮累积速率及其被矿化的难易程度共同作用的结果。于维水等[31]指出,长期耕作施肥影响土壤有机碳、全氮组分分配,黑土和潮土粉粒和黏粒中全氮占比较大,且长期耕作秸秆还田提高了砂粒中全氮在土壤全氮的比例分配,本研究发现类似现象,在不同颗粒全氮组分中,粉粒中全氮占比最大,在30.2%— 72.2%,砂粒中全氮占比最小,在2.4%—35.9%,但砂粒中全氮所占比例随耕作时间延长而增加,其对全氮的贡献度增加[18],从而促进了氮的活化和转化利用,有利于土壤微生物分解利用和提高氮的利用率。
3.2 长期耕作对土壤碳氮比变化的影响
土壤碳氮比通常被认为是土壤碳矿化能力的标志,低的碳氮比可以加快微生物的分解和氮的矿化速率[8,9,10],不利于碳的固存。陈洁等[18]指出长期施肥条件下,土壤碳氮比低于10,李彤等[15]研究认为长期耕作条件下难降解组分颗粒组分碳氮比比值为8.4— 9.4,低于森林土壤和草地。本研究结果表明,长期耕作条件下土壤总的碳氮比比值为4.7—6.4,耕作提高了土壤总的碳氮比,与雷军等[36]、黄彩变等[37]研究结果类似。这是因为相比未耕作土壤,总体上长期耕作增加了凋落物和根系残留有机物的输入,表层土壤有机碳增加速度大于全氮的增加速度,提高了土壤总的碳氮比。砂粒中碳氮比的降低,可能是由于随着耕作时间延长,土壤氮投入量持续增加,加快了砂粒中微生物分解和氮的矿化速率[10],加快了有机物的分解矿化速度,不利于砂粒有机碳的累积。耕作0—5 a,砂粒中的碳氮比高于粉粒和黏粒中的碳氮比,但是5 a后粉粒中碳氮比最高,主要是耕作初期砂粒中微生物活性较低,减弱了原有有机碳和新鲜有机碳的分解矿化[24],增加了砂粒中有机碳的积累,而随着耕作时间的延长,土壤机械破碎水平和频度的提高,加速了大团聚体向小团聚体和微团聚体的转化,耕作20 a,兰州湾、31团和普惠农场53—250 μm的小微团聚体（附表1）,相比未耕作土壤显著增加37.4%、111.6%和121.7%,造成土壤各组分中碳氮比分配比例的变化。4 结论
新疆干旱荒漠区长期耕作增加了土壤有机碳、全氮和不同颗粒中有机碳、全氮含量。不同颗粒组分中,以粉粒中的有机碳和全氮含量最高,砂粒中的有机碳和全氮含量最低。耕作改变了各颗粒组分中有机碳或全氮含量在土壤有机碳或全氮中的占比,其中粉粒中有机碳、全氮含量成为土壤有机碳、全氮分配的主体,分别占土壤有机碳的43.3%—56.1%和全氮的30.2%—72.2%;同时,耕作提高了土壤中和粉粒中碳氮比,降低了砂粒中碳氮比。长期耕作增加了新疆干旱荒漠区农田生态系统土壤有机碳和全氮的累积,该措施有助于干旱荒漠区农业土壤固碳减排与生产力的长期稳定。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
DOI:10.5846/stxb201310212541URL [本文引用: 1]
土壤固碳功能和固碳潜力已成为全球气候变化和陆地生态系统研究的重点。草地土壤有机碳库,作为陆地土壤有机碳库的重要组成部分,其较小幅度的波动,将会影响整个陆地生态系统碳循环,进而影响全球气候变化。因此,深入研究草地土壤固碳功能和固碳潜力对于适应和减缓气候变化具有重要意义。在土壤固碳潜力相关概念界定基础上,结合《2006年IPCC国家温室气体清单指南》,从样点及区域尺度上综述了目前关于草地土壤固碳潜力的一般估算方法,同时对各类方法的特点及适用性进行了评述,提出了草地生态系统固碳潜力研究概念模型。最后在对草地土壤固碳的影响因素及固碳措施总结的基础上,阐明了草地土壤有机碳固定研究中存在的问题和发展前景。
DOI:10.5846/stxb201310212541URL [本文引用: 1]
土壤固碳功能和固碳潜力已成为全球气候变化和陆地生态系统研究的重点。草地土壤有机碳库,作为陆地土壤有机碳库的重要组成部分,其较小幅度的波动,将会影响整个陆地生态系统碳循环,进而影响全球气候变化。因此,深入研究草地土壤固碳功能和固碳潜力对于适应和减缓气候变化具有重要意义。在土壤固碳潜力相关概念界定基础上,结合《2006年IPCC国家温室气体清单指南》,从样点及区域尺度上综述了目前关于草地土壤固碳潜力的一般估算方法,同时对各类方法的特点及适用性进行了评述,提出了草地生态系统固碳潜力研究概念模型。最后在对草地土壤固碳的影响因素及固碳措施总结的基础上,阐明了草地土壤有机碳固定研究中存在的问题和发展前景。
URL [本文引用: 1]
0-20 cm soil samples were collected from an 18-year wheat-maize rotation field on the North China Plain to study the effects of long-term fertilization on the contents and storages of soil particulate organic carbon (POC), particulate organic nitrogen (PON), incorporated organic carbon (IOC), and incorporated organic nitrogen (ION). The long-term fertilization experiment was designed to include 7 treatments, i.e., chemical NPK (NPK), organic manure (OM), 1/2 organic manure plus 1/2 chemical NPK (1/2OMN), chemical NP (NP), chemical PK (PK), chemical NK (NK), and control (CK). After 18 years experiment, all the fertilization treatments showed higher contents of soil POC, PON, IOC and ION, higher proportions of soil POC to soil total organic carbon (TOC) and of soil PON to soil total nitrogen (TON), and higher C/N ratio of soil particulate organic matter. The storages of soil POC and PON under fertilization treatments were increased by 11.7%-196.8% and 13.0%-152.2%, respectively, compared with the control. The contribution of soil POC to the increased storage of soil TOC ranged from 31.5% to 67.3%, and that of soil PON to the increased storage of soil TON ranged from 14.3% to 100.0%. The storages of soil IOC and ION under fertilization treatments increased by 2.0%-75.0% and 0.0%-69.8%, respectively, compared with the control. Among the fertilization treatments, treatment OM had the highest storages of soil POC, PON, IOC and ION, followed by treatment 1/2OMN, and the treatments of applying chemical fertilizers alone. Balanced application of chemical fertilizers (treatment NPK) showed higher storages of soil POC, PON, IOC and ION than imbalanced application (treatments NP, PK, and NK). It was suggested that applying organic manure or its combination with chemical NPK and the balanced application of chemical NPK could be the keys for the increase of soil POC, PON, IOC and ION contents and storages.
URL [本文引用: 1]
0-20 cm soil samples were collected from an 18-year wheat-maize rotation field on the North China Plain to study the effects of long-term fertilization on the contents and storages of soil particulate organic carbon (POC), particulate organic nitrogen (PON), incorporated organic carbon (IOC), and incorporated organic nitrogen (ION). The long-term fertilization experiment was designed to include 7 treatments, i.e., chemical NPK (NPK), organic manure (OM), 1/2 organic manure plus 1/2 chemical NPK (1/2OMN), chemical NP (NP), chemical PK (PK), chemical NK (NK), and control (CK). After 18 years experiment, all the fertilization treatments showed higher contents of soil POC, PON, IOC and ION, higher proportions of soil POC to soil total organic carbon (TOC) and of soil PON to soil total nitrogen (TON), and higher C/N ratio of soil particulate organic matter. The storages of soil POC and PON under fertilization treatments were increased by 11.7%-196.8% and 13.0%-152.2%, respectively, compared with the control. The contribution of soil POC to the increased storage of soil TOC ranged from 31.5% to 67.3%, and that of soil PON to the increased storage of soil TON ranged from 14.3% to 100.0%. The storages of soil IOC and ION under fertilization treatments increased by 2.0%-75.0% and 0.0%-69.8%, respectively, compared with the control. Among the fertilization treatments, treatment OM had the highest storages of soil POC, PON, IOC and ION, followed by treatment 1/2OMN, and the treatments of applying chemical fertilizers alone. Balanced application of chemical fertilizers (treatment NPK) showed higher storages of soil POC, PON, IOC and ION than imbalanced application (treatments NP, PK, and NK). It was suggested that applying organic manure or its combination with chemical NPK and the balanced application of chemical NPK could be the keys for the increase of soil POC, PON, IOC and ION contents and storages.
[本文引用: 1]
[本文引用: 1]
[本文引用: 1]
[本文引用: 1]
URLPMID:15228001 [本文引用: 2]
According to the rotor size of Mandal RC5C and Stoks' law, a segregation procedure for soil particle size fractionation was designed, and used for the particle separation of Huangmian soil(Calcaric cambisols, FAO), Huihe soil (Haplic greyxems, FAO), and Helu soil(Calcic kastanozems, FAO) in the Loess Plateau of China, and of Orthic Brown Chernozem, and Orthic Black Chernozem in Canadian Prairie. The fractionation results of the 5 soils by using this procedure were in line with those of the standard pipette method.
URLPMID:15228001 [本文引用: 2]
According to the rotor size of Mandal RC5C and Stoks' law, a segregation procedure for soil particle size fractionation was designed, and used for the particle separation of Huangmian soil(Calcaric cambisols, FAO), Huihe soil (Haplic greyxems, FAO), and Helu soil(Calcic kastanozems, FAO) in the Loess Plateau of China, and of Orthic Brown Chernozem, and Orthic Black Chernozem in Canadian Prairie. The fractionation results of the 5 soils by using this procedure were in line with those of the standard pipette method.
[本文引用: 1]
DOI:10.1016/j.fcr.2013.08.007URL [本文引用: 1]
DOI:10.1007/s003740050019URL [本文引用: 2]
Most models for the turnover of soil organic matter (SOM) include a compartment that is either considered inert, or has a very slow turnover time (refractory SOM; RSOM). The RSOM content of soils varies markedly between sites, and knowledge of its size and variability are essential for determining whether soils behave as sources or sinks of atmospheric CO2. It has also been suggested that the accurate specification of RSOM pools is essential to modelling studies, and that uncertainty in estimates of the size of RSOM pool could be a major source of error in modelling soil organic C. In this paper, current SOM models are reviewed, and approaches to modelling RSOM and its significance are discussed. Simulations of SOM turnover for the Rothamsted Broadbalk winter wheat experiment using the Rothamsted C model and CENTURY are presented as examples.
DOI:10.5846/stxb201302130263URL [本文引用: 2]
利用67个样点数据,研究了青藏高原高寒草原生态系统土壤碳氮比的分布特征.结果表明:(1)在水平方向上,土壤碳氮比呈现出西北高、东南低的总体态势和斑块状交错分布的格局,碳氮比的高值区主要集中在藏北高原腹地和喜马拉雅山北麓湖盆区,不同草地型和不同自然地带土壤碳氮比差异显著;(2)土壤剖面自上而下,不同草地型碳氮比可分为低-高-低型、由高到低型、由低到高型、高-低-高-低型和高-低-高型等5个类型.表土层(0-20 cm)与底土层(30-40 cm)土壤碳氮比差异显著;(3)土壤碳氮比与与最冷月均气温、年均蒸发量、年均相对湿度和土壤全氮含量呈极显著正相关关系,而与年均日照时数、年均气温、速效钾含量呈极显著负相关关系,这些环境因素对土壤碳氮比影响从大到小的顺序是年均相对湿度 > 年均日照时数 > 最冷月均气温 > 年均气温 > 年均蒸发量 > 土壤全氮含量 > 土壤速效钾含量.
DOI:10.5846/stxb201302130263URL [本文引用: 2]
利用67个样点数据,研究了青藏高原高寒草原生态系统土壤碳氮比的分布特征.结果表明:(1)在水平方向上,土壤碳氮比呈现出西北高、东南低的总体态势和斑块状交错分布的格局,碳氮比的高值区主要集中在藏北高原腹地和喜马拉雅山北麓湖盆区,不同草地型和不同自然地带土壤碳氮比差异显著;(2)土壤剖面自上而下,不同草地型碳氮比可分为低-高-低型、由高到低型、由低到高型、高-低-高-低型和高-低-高型等5个类型.表土层(0-20 cm)与底土层(30-40 cm)土壤碳氮比差异显著;(3)土壤碳氮比与与最冷月均气温、年均蒸发量、年均相对湿度和土壤全氮含量呈极显著正相关关系,而与年均日照时数、年均气温、速效钾含量呈极显著负相关关系,这些环境因素对土壤碳氮比影响从大到小的顺序是年均相对湿度 > 年均日照时数 > 最冷月均气温 > 年均气温 > 年均蒸发量 > 土壤全氮含量 > 土壤速效钾含量.
[本文引用: 3]
[本文引用: 3]
DOI:10.11674/zwyf.2015.0211URL [本文引用: 1]
【目的】秸秆还田作为一种有效的秸秆处理方式不仅能够提高土壤肥力，增加作物产量，还可以缓解农田生态压力。研究稻麦轮作系统下不同秸秆还田量对土壤活性有机碳库、酶活性和作物产量的短期影响，可为提出适宜当地生产的秸秆还田量提供理论依据。【方法】利用稻麦轮作农田定位试验进行了研究。采用随机区组设计，设7个处理，以稻麦季秸秆均不还田为对照处理(CK)，6个不同秸秆还田量处理。测定了秸秆还田后土壤活性有机碳库和土壤酶活性的变化，稻麦产量以及三者之间的相关关系。【结果】 1)与秸秆不还田处理相比，试验范围内的秸秆还田量能在一定程度上提高土壤活性碳组分的含量和土壤酶活性，并能增加水稻和小麦的产量及其构成因素;2)土壤总有机碳和微生物生物量碳的含量随着秸秆还田量增加，增幅呈先增大后减小的趋势，以连续两季50%秸秆还田量处理下显著较高，而水溶性有机碳、活性有机碳含量和碳库管理指数在连续两季25%秸秆还田量处理下最高;3)相比秸秆不还田处理，连续两季25%秸秆还田量对土壤脲酶、过氧化氢酶和蔗糖酶活性的影响均最显著;4)水稻和小麦的产量均为在连续两季25%和50%秸秆还田量处理下增产较显著，与秸秆不还田相比，水稻增产达9.0%，小麦增产达11.45%;5)土壤碳库、土壤酶活性以及水稻和小麦产量之间均存在显著相关。【结论】在本试验条件下，连续两季25%和50%秸秆还田量表现出显著提高土壤碳汇能力和增加作物产量的优势。
DOI:10.11674/zwyf.2015.0211URL [本文引用: 1]
【目的】秸秆还田作为一种有效的秸秆处理方式不仅能够提高土壤肥力，增加作物产量，还可以缓解农田生态压力。研究稻麦轮作系统下不同秸秆还田量对土壤活性有机碳库、酶活性和作物产量的短期影响，可为提出适宜当地生产的秸秆还田量提供理论依据。【方法】利用稻麦轮作农田定位试验进行了研究。采用随机区组设计，设7个处理，以稻麦季秸秆均不还田为对照处理(CK)，6个不同秸秆还田量处理。测定了秸秆还田后土壤活性有机碳库和土壤酶活性的变化，稻麦产量以及三者之间的相关关系。【结果】 1)与秸秆不还田处理相比，试验范围内的秸秆还田量能在一定程度上提高土壤活性碳组分的含量和土壤酶活性，并能增加水稻和小麦的产量及其构成因素;2)土壤总有机碳和微生物生物量碳的含量随着秸秆还田量增加，增幅呈先增大后减小的趋势，以连续两季50%秸秆还田量处理下显著较高，而水溶性有机碳、活性有机碳含量和碳库管理指数在连续两季25%秸秆还田量处理下最高;3)相比秸秆不还田处理，连续两季25%秸秆还田量对土壤脲酶、过氧化氢酶和蔗糖酶活性的影响均最显著;4)水稻和小麦的产量均为在连续两季25%和50%秸秆还田量处理下增产较显著，与秸秆不还田相比，水稻增产达9.0%，小麦增产达11.45%;5)土壤碳库、土壤酶活性以及水稻和小麦产量之间均存在显著相关。【结论】在本试验条件下，连续两季25%和50%秸秆还田量表现出显著提高土壤碳汇能力和增加作物产量的优势。
[本文引用: 1]
DOI:10.1016/j.soilbio.2012.11.009URL [本文引用: 1]
DOI:10.1016/j.soilbio.2016.03.011URL [本文引用: 1]
DOI:10.3864/j.issn.0578-1752.2017.05.009URL [本文引用: 2]
【Objective】Conservation tillage has been applied widely in the arid region of Northwest China, it is an important technical measure of agricultural production, explorating the effect of conservation tillage on soil fertility and soil microbial community structure and will help the sustainable development of agricultural production. This experiment from the angle of the combination of soil physico-chemical properties and microorganism to investigate the effect of conservation tillage on soil microbial spatial structure, and the relevance of abundance of microbial communities and soil physico-chemical properties of dryland wheat field, providing a theoretical basis and practical support measures for the promotion of conservation tillage.【Method】In this experiment, the soil of arid region in Northwest China was used as the research object, compared to conservational plow tillage (PT), two kinds of conservation tillage methods, including chisel plow tillage(CPT) and zero tillage(ZT) were designed, the indicators of soil physico-chemical properties and the abundance of microbial communities were measured by using real-time PCR, and the relations between the spatial distribution of microbial communities and soil physico-chemical properties and conservation tillage were analyzed.【Result】Long-term conservation tillage had a significant effect on the environment of dryland wheat field, the abundance of soil fungi and bacterial communities had different effects with different tillage methods, they showed different levels of response to the three tillages. In different tillage methods, the spatial distribution of soil microbe was uneven, continuity was poor, higher spatial variability, and showed a strong spatial aggregated distribution. There were also significant effects of tillage method on soil physico-chemical properties and enzyme activities, compared with traditional tillage, chisel plow tillage and zero tillage could significantly improve soil clay, water, total nitrogen, ammonium nitrogen content and urease and invertase activities. The results of canonical principal component analysis (CPCA) showed that the changes of soil microbial community abundance and physico-chemical properties were mainly affected by tillage methods, and the soil microbial community abundance is closely related to physico-chemical properties, under the zero tillage mode, the content of soil clay, water and ammonium nitrogen significantly affected the distribution of soil bacterial community, and under chisel plow tillage mode, the content of soil soluble carbon and the activity of catalase significantly affected the distribution of soil fungal communities.【Conclusion】Using conservation tillage in dryland wheat field could affect the abundance and the spatial distribution of soil microbial communities, and significantly affected soil physico-chemical properties, and then affecting the spatial structure of soil microbes. Simultaneously, soil moisture and the contents of carbon and nitrogen were respectively significantly affected soil bacteria and fungi community abundance.
DOI:10.3864/j.issn.0578-1752.2017.05.009URL [本文引用: 2]
【Objective】Conservation tillage has been applied widely in the arid region of Northwest China, it is an important technical measure of agricultural production, explorating the effect of conservation tillage on soil fertility and soil microbial community structure and will help the sustainable development of agricultural production. This experiment from the angle of the combination of soil physico-chemical properties and microorganism to investigate the effect of conservation tillage on soil microbial spatial structure, and the relevance of abundance of microbial communities and soil physico-chemical properties of dryland wheat field, providing a theoretical basis and practical support measures for the promotion of conservation tillage.【Method】In this experiment, the soil of arid region in Northwest China was used as the research object, compared to conservational plow tillage (PT), two kinds of conservation tillage methods, including chisel plow tillage(CPT) and zero tillage(ZT) were designed, the indicators of soil physico-chemical properties and the abundance of microbial communities were measured by using real-time PCR, and the relations between the spatial distribution of microbial communities and soil physico-chemical properties and conservation tillage were analyzed.【Result】Long-term conservation tillage had a significant effect on the environment of dryland wheat field, the abundance of soil fungi and bacterial communities had different effects with different tillage methods, they showed different levels of response to the three tillages. In different tillage methods, the spatial distribution of soil microbe was uneven, continuity was poor, higher spatial variability, and showed a strong spatial aggregated distribution. There were also significant effects of tillage method on soil physico-chemical properties and enzyme activities, compared with traditional tillage, chisel plow tillage and zero tillage could significantly improve soil clay, water, total nitrogen, ammonium nitrogen content and urease and invertase activities. The results of canonical principal component analysis (CPCA) showed that the changes of soil microbial community abundance and physico-chemical properties were mainly affected by tillage methods, and the soil microbial community abundance is closely related to physico-chemical properties, under the zero tillage mode, the content of soil clay, water and ammonium nitrogen significantly affected the distribution of soil bacterial community, and under chisel plow tillage mode, the content of soil soluble carbon and the activity of catalase significantly affected the distribution of soil fungal communities.【Conclusion】Using conservation tillage in dryland wheat field could affect the abundance and the spatial distribution of soil microbial communities, and significantly affected soil physico-chemical properties, and then affecting the spatial structure of soil microbes. Simultaneously, soil moisture and the contents of carbon and nitrogen were respectively significantly affected soil bacteria and fungi community abundance.
DOI:10.3864/j.issn.0578-1752.2018.19.009URL [本文引用: 2]
【Objective】 Land use conversion from native vegetation to cropland has a great impact on soil organic carbon (SOC) storage. Recently, the area of croplands that converted from native forests or grasslands increases gradually in the southeastern part of Tibetan Plateau, yet its influence on SOC fractionation and turnover remains unknown. It is therefore in great need to understand the extent and mechanisms that difference in land use type has exerted on SOC storage, which will provide scientific basis for sustainable management of agricultural soils in southeastern Tibet. 【Method】In the present study, soil samples were collected from cropland that had been cultivated for more than 50 years, as well as adjacent native forest and grassland. A combination of physical and chemical method was conducted to partition the SOC into different fractions. For each SOC fractions, the present in soil mass, SOC content and stable carbon isotope composition (δ13C) were analyzed to investigate the differences in SOC fractionation and turnover under different land use types. 【Result】 The SOC that stored in top 20 cm soil of cropland was (39.4±2.0) Mg C·hm-2, which was 52% and 45% lower than native forest ((81.5±8.5) Mg C·hm-2) and grassland ((71.4±7.3) Mg C·hm-2), respectively. Compared to native forests and grasslands, long-term cultivation led to a decrease of 63.4%-70.8% in the mass of coarse particulate organic matter (cPOM), whereas the mass of microaggregate (μagg) and easily dispersed silt and clay (dSilt+Clay) increased 10.0%—25.9% and 65.7%-86.2%, respectively. The C content in each SOC fraction was significantly lower in cropland soils than that in forest and grassland soils. SOC content in cropland soils was 51.7%-58.1% lower than that in forest and grassland soils. The SOC contents of unprotected C, physically protected C and biochemically protected C pool reduced 79.8%-86.3%, 72.4%-73.1% and 32.4%-39.8% in cropland soils, respectively, and were positively correlated with changes in total SOC content following land use conversion. The SOC content in chemically protected C pool, however, was not affected by land use conversion. The C/N ratio and δ13C differed among different SOC fractions and three land use types. The C/N ratio of cPOM in cropland soils (10.0±0.5) was significantly lower than forest soils (13.5±0.4), whereas its δ13C value ((-21.6±0.5) ‰) was significantly higher than forest soils (-23.6±0.4) ‰. The δ13C values of microaggregate-protected particulate organic matter (iPOM) and non-hydrolyzable fraction (NH-dSilt+Clay and NH-μSilt+Clay) were comparably lower (-25.3‰- -27.2‰) than other SOC fractions, and had significantly lower C/N ratio in cropland soils (8.4-9.4) compared to forest soils (13.5-15.9). 【Conclusion】Results of the present study indicated that long-term cultivation had resulted in c.a. 50% reduce in SOC stock compared to native vegetation in southeastern Tibet. Agricultural cultivation strongly promoted the turnover of unprotected particulate organic matter, and suppressed the formation of more stabilized SOC, such as microaggregate-protected SOC fraction, which contributed great proportions to the dramatic decrease in SOC storage. Therefore, implement of no-tillage or other protective management would be necessary to reduce the negative influence of agricultural land use on SOC storage and to maintain the sustainable utilization of natural soil sources in southeastern Tibet.
DOI:10.3864/j.issn.0578-1752.2018.19.009URL [本文引用: 2]
【Objective】 Land use conversion from native vegetation to cropland has a great impact on soil organic carbon (SOC) storage. Recently, the area of croplands that converted from native forests or grasslands increases gradually in the southeastern part of Tibetan Plateau, yet its influence on SOC fractionation and turnover remains unknown. It is therefore in great need to understand the extent and mechanisms that difference in land use type has exerted on SOC storage, which will provide scientific basis for sustainable management of agricultural soils in southeastern Tibet. 【Method】In the present study, soil samples were collected from cropland that had been cultivated for more than 50 years, as well as adjacent native forest and grassland. A combination of physical and chemical method was conducted to partition the SOC into different fractions. For each SOC fractions, the present in soil mass, SOC content and stable carbon isotope composition (δ13C) were analyzed to investigate the differences in SOC fractionation and turnover under different land use types. 【Result】 The SOC that stored in top 20 cm soil of cropland was (39.4±2.0) Mg C·hm-2, which was 52% and 45% lower than native forest ((81.5±8.5) Mg C·hm-2) and grassland ((71.4±7.3) Mg C·hm-2), respectively. Compared to native forests and grasslands, long-term cultivation led to a decrease of 63.4%-70.8% in the mass of coarse particulate organic matter (cPOM), whereas the mass of microaggregate (μagg) and easily dispersed silt and clay (dSilt+Clay) increased 10.0%—25.9% and 65.7%-86.2%, respectively. The C content in each SOC fraction was significantly lower in cropland soils than that in forest and grassland soils. SOC content in cropland soils was 51.7%-58.1% lower than that in forest and grassland soils. The SOC contents of unprotected C, physically protected C and biochemically protected C pool reduced 79.8%-86.3%, 72.4%-73.1% and 32.4%-39.8% in cropland soils, respectively, and were positively correlated with changes in total SOC content following land use conversion. The SOC content in chemically protected C pool, however, was not affected by land use conversion. The C/N ratio and δ13C differed among different SOC fractions and three land use types. The C/N ratio of cPOM in cropland soils (10.0±0.5) was significantly lower than forest soils (13.5±0.4), whereas its δ13C value ((-21.6±0.5) ‰) was significantly higher than forest soils (-23.6±0.4) ‰. The δ13C values of microaggregate-protected particulate organic matter (iPOM) and non-hydrolyzable fraction (NH-dSilt+Clay and NH-μSilt+Clay) were comparably lower (-25.3‰- -27.2‰) than other SOC fractions, and had significantly lower C/N ratio in cropland soils (8.4-9.4) compared to forest soils (13.5-15.9). 【Conclusion】Results of the present study indicated that long-term cultivation had resulted in c.a. 50% reduce in SOC stock compared to native vegetation in southeastern Tibet. Agricultural cultivation strongly promoted the turnover of unprotected particulate organic matter, and suppressed the formation of more stabilized SOC, such as microaggregate-protected SOC fraction, which contributed great proportions to the dramatic decrease in SOC storage. Therefore, implement of no-tillage or other protective management would be necessary to reduce the negative influence of agricultural land use on SOC storage and to maintain the sustainable utilization of natural soil sources in southeastern Tibet.
URL [本文引用: 1]
【目的】为阐明长期施肥对红壤和潮土不同大小颗粒有机碳含量和分布的影响，探讨土壤持续利用培肥模式。【方法】采集17年长期施用不同肥料后的红壤和潮土，通过物理分组方法得到砂粒、粗粉粒、细粉粒、粗黏粒及细黏粒，观测了不同颗粒有机碳含量和分布的状况。【结果】与不施肥（CK）相比，施用有机肥（M、NPKM）和秸秆还田（NPKS）均可显著增加红壤和潮土总有机碳及不同颗粒有机碳组分的含量，其中以配施有机肥效果最为明显。施化肥有利于增加细黏粒的有机碳含量。各级颗粒中以砂粒的有机碳（POC）含量增幅最高，在红壤和潮土中分别增加1.7～3.8倍和1.9～2.8倍，对施肥最敏感。施肥使红壤和潮土有机碳在砂粒中的分布比例分别提高了37.7%～91.5%和63.6%；黏粉粒中有机碳的分布比例因颗粒大小不同而有差异，但总体上施肥降低了黏粉粒中矿物结合态有机碳（MOC）的分布比例，相应地施肥提高了POC与MOC的比率（WPOC/WMOC），改良了土壤有机碳性质。【结论】长期施肥下壤质红壤比轻质潮土固存了更多的有机碳。配施有机肥和秸秆还田是提高两种土壤不同颗粒有机碳含量的有效措施。
URL [本文引用: 1]
【目的】为阐明长期施肥对红壤和潮土不同大小颗粒有机碳含量和分布的影响，探讨土壤持续利用培肥模式。【方法】采集17年长期施用不同肥料后的红壤和潮土，通过物理分组方法得到砂粒、粗粉粒、细粉粒、粗黏粒及细黏粒，观测了不同颗粒有机碳含量和分布的状况。【结果】与不施肥（CK）相比，施用有机肥（M、NPKM）和秸秆还田（NPKS）均可显著增加红壤和潮土总有机碳及不同颗粒有机碳组分的含量，其中以配施有机肥效果最为明显。施化肥有利于增加细黏粒的有机碳含量。各级颗粒中以砂粒的有机碳（POC）含量增幅最高，在红壤和潮土中分别增加1.7～3.8倍和1.9～2.8倍，对施肥最敏感。施肥使红壤和潮土有机碳在砂粒中的分布比例分别提高了37.7%～91.5%和63.6%；黏粉粒中有机碳的分布比例因颗粒大小不同而有差异，但总体上施肥降低了黏粉粒中矿物结合态有机碳（MOC）的分布比例，相应地施肥提高了POC与MOC的比率（WPOC/WMOC），改良了土壤有机碳性质。【结论】长期施肥下壤质红壤比轻质潮土固存了更多的有机碳。配施有机肥和秸秆还田是提高两种土壤不同颗粒有机碳含量的有效措施。
DOI:10.1002/(ISSN)1522-2624URL [本文引用: 3]
[本文引用: 2]
[本文引用: 2]
DOI:10.1007/BF00341480URL [本文引用: 2]
[本文引用: 1]
[本文引用: 1]
[本文引用: 1]
[本文引用: 1]
DOI:10.11820/dlkxjz.2006.04.007URL [本文引用: 1]
Terrestrial carbon cycle and nitrogen cycle are closely coupled. Some factors, such as temperature, water and CO2 concentration, were more considered in the previous carbon researches than the nitrogen because of the complexity of nitrogen cycle, but this situation has changed in recent years. Nitrogen has great effects on the plant photosynthesis, organic matter decomposition, carbon allocation and the responses of ecosystem when the atmospheric CO2 concentration increases. There are generally three types of carbon models to consider nitrogen limitation on carbon assimilation: (1) static models: these type models usually use a constant soil fertility index or leaf nitrogen concentration and are fit for a site or district where the nitrogen variability can be neglected; (2) soil nitrogen limitation models: these models can maintain stable nitrogen budgets and dynamic soil nitrogen can turn the potential NPP to actual NPP; (3) leaf nitrogen limitation models: such models are similar to soil nitrogen limitation but feature a further dynamic leaf- level nitrogen regulation of NPP. The common approach uses relative leaf nitrogen concentration to scale down proportionally either the maximum Rubisco or the NPP. Although the three type models all consider the nitrogen effects on carbon cycle, they may produce great uncertainty in carbon research because of the partly understanding of the interaction between carbon and nitrogen. Future studies should focus on both the experiment and observation about the nitrogen feedbacks on carbon cycle and the development of integrated dynamic ecosystem models that can describe the interaction of carbon and nitrogen cycle, contributing to decreasing the uncertainty in the carbon research.
DOI:10.11820/dlkxjz.2006.04.007URL [本文引用: 1]
Terrestrial carbon cycle and nitrogen cycle are closely coupled. Some factors, such as temperature, water and CO2 concentration, were more considered in the previous carbon researches than the nitrogen because of the complexity of nitrogen cycle, but this situation has changed in recent years. Nitrogen has great effects on the plant photosynthesis, organic matter decomposition, carbon allocation and the responses of ecosystem when the atmospheric CO2 concentration increases. There are generally three types of carbon models to consider nitrogen limitation on carbon assimilation: (1) static models: these type models usually use a constant soil fertility index or leaf nitrogen concentration and are fit for a site or district where the nitrogen variability can be neglected; (2) soil nitrogen limitation models: these models can maintain stable nitrogen budgets and dynamic soil nitrogen can turn the potential NPP to actual NPP; (3) leaf nitrogen limitation models: such models are similar to soil nitrogen limitation but feature a further dynamic leaf- level nitrogen regulation of NPP. The common approach uses relative leaf nitrogen concentration to scale down proportionally either the maximum Rubisco or the NPP. Although the three type models all consider the nitrogen effects on carbon cycle, they may produce great uncertainty in carbon research because of the partly understanding of the interaction between carbon and nitrogen. Future studies should focus on both the experiment and observation about the nitrogen feedbacks on carbon cycle and the development of integrated dynamic ecosystem models that can describe the interaction of carbon and nitrogen cycle, contributing to decreasing the uncertainty in the carbon research.
URL [本文引用: 2]
A paired-site design was adopted to quantitatively evaluate and compare the changes of soil properties between reclaimed lands from zonal and intrazonal grasslands, which would be applied to develop scientific strategies and programs for land use in the agro-pastoral ecotone of northern China. The results showed that the soil texture became coarse after reclamation, accordingly, soil bulk density increased and soil water holding capacity reduced;The contents of soil organic carbon, dissoluble organic carbon, available phosphorus, available kalium and soil available trace elements decreased. The reclamation of zonal grassland led to the shortage of available Fe and Mn in the soil. It would make a strong impact on growth of crop. Based on the analysis and comparison of soil properties changes of reclamation land in the zonal and intrazonal grasslands, it was concluded that the farmers should reserve high crop residue in the farmland, postpone properly the ploughing time for the sake of reducing wind erosion, and improve soil quality through returning straw to field and applying organic fertilizer. Meanwhile it would be important measures to stop reclaiming zonal grassland, to return the crop field into grassland and scientifically use the intrazonal grassland in agro-pastoral ecotone of northern China.
URL [本文引用: 2]
A paired-site design was adopted to quantitatively evaluate and compare the changes of soil properties between reclaimed lands from zonal and intrazonal grasslands, which would be applied to develop scientific strategies and programs for land use in the agro-pastoral ecotone of northern China. The results showed that the soil texture became coarse after reclamation, accordingly, soil bulk density increased and soil water holding capacity reduced;The contents of soil organic carbon, dissoluble organic carbon, available phosphorus, available kalium and soil available trace elements decreased. The reclamation of zonal grassland led to the shortage of available Fe and Mn in the soil. It would make a strong impact on growth of crop. Based on the analysis and comparison of soil properties changes of reclamation land in the zonal and intrazonal grasslands, it was concluded that the farmers should reserve high crop residue in the farmland, postpone properly the ploughing time for the sake of reducing wind erosion, and improve soil quality through returning straw to field and applying organic fertilizer. Meanwhile it would be important measures to stop reclaiming zonal grassland, to return the crop field into grassland and scientifically use the intrazonal grassland in agro-pastoral ecotone of northern China.
[本文引用: 1]
[本文引用: 1]
[本文引用: 1]
DOI:10.2136/sssaj2004.5070URL [本文引用: 1]
DOI:10.1016/j.still.2017.02.001URL [本文引用: 1]
DOI:10.1016/0038-0717(94)90086-8URL [本文引用: 1]
URL [本文引用: 1]
URL [本文引用: 1]
DOI:10.3864/j.issn.0578-1752.2015.15.010URL [本文引用: 2]
【Objective】Labile nitrogen (Lab-N) and recalcitrant nitrogen (Rec-N) are two important components of soil nitrogen, and their ratio has an effect on nitrogen turnover and sequestration properties. Therefore, it is important to study the characteristics of Lab-N and Rec-N under different long-term fertilization systems for better nitrogen management and soil fertility improvement. 【Method】Lab-N, Rec-N and their ratio were studied by particle size-density separation method under four long-term fertilizer treatments, namely no fertilizer (CK), chemical fertilizer (NPK), chemical fertilizer combined with straw (NPKS), and chemical fertilizer combined with manure (NPKM), of three upland soils (Gongzhuling black soil, Zhengzhou fluvo-aquic soil and Qiyang red soil) and Wangcheng paddy soil that collected from east China. 【Result】 The average Lab-N in upland soils was 0.15 g·kg-1, much lower than that of paddy soil (0.22 g·kg-1). While Lab-N/TN in upland soils was much higher than that in paddy soil. After 23 years, the Total N (TN) of the upland soils under CK treatment decreased significantly (7.5%-9.7%) compared with the start of the experiment, while in the paddy soil the TN increased by 11.5%. The TN contents in all soils under NPK treatment were significantly higher than that of CK treatment. The Lab-N of red soil under NPK treatment was significantly lower than that of CK treatment, while for other soils there were no significant differences under two treatments. The TN contents of all soils under NPKS treatment increased significantly compared with CK treatment, while there was no significant difference in the Lab-N and Lab-N/TN between black soil and paddy soil. The Lab-N of red soil under NPKS treatment decreased significantly compared with CK treatment, while the Lab-N of fluvo-aquic soil increased significantly. The TN, Lab-N and the Lab-N/TN in the upland soils under NPKM treatment increased significantly. And the black soil increased the most by 85.0%, 106.0% and 4.2%; there was no significant difference in the Lab-N and Lab-N/TN in the paddy soil between NPKM and CK treatments. Both the Rec-N and the TN in four soils under four different treatments were in the order of NPKM>NPKS>NPK>CK. The Rce-N/TN under NPKM decreased significantly compared with CK treatment. 【Conclusion】 Both the Lab-N and the Lab-N/TN in upland soils were more susceptible to fertilizer application compared with paddy soil. The TN, Lab-N and Lab-N/TN all increased significantly under NPKM treatment, and the improvement effect was in the order of NPKM>NPKS>NPK.
DOI:10.3864/j.issn.0578-1752.2015.15.010URL [本文引用: 2]
【Objective】Labile nitrogen (Lab-N) and recalcitrant nitrogen (Rec-N) are two important components of soil nitrogen, and their ratio has an effect on nitrogen turnover and sequestration properties. Therefore, it is important to study the characteristics of Lab-N and Rec-N under different long-term fertilization systems for better nitrogen management and soil fertility improvement. 【Method】Lab-N, Rec-N and their ratio were studied by particle size-density separation method under four long-term fertilizer treatments, namely no fertilizer (CK), chemical fertilizer (NPK), chemical fertilizer combined with straw (NPKS), and chemical fertilizer combined with manure (NPKM), of three upland soils (Gongzhuling black soil, Zhengzhou fluvo-aquic soil and Qiyang red soil) and Wangcheng paddy soil that collected from east China. 【Result】 The average Lab-N in upland soils was 0.15 g·kg-1, much lower than that of paddy soil (0.22 g·kg-1). While Lab-N/TN in upland soils was much higher than that in paddy soil. After 23 years, the Total N (TN) of the upland soils under CK treatment decreased significantly (7.5%-9.7%) compared with the start of the experiment, while in the paddy soil the TN increased by 11.5%. The TN contents in all soils under NPK treatment were significantly higher than that of CK treatment. The Lab-N of red soil under NPK treatment was significantly lower than that of CK treatment, while for other soils there were no significant differences under two treatments. The TN contents of all soils under NPKS treatment increased significantly compared with CK treatment, while there was no significant difference in the Lab-N and Lab-N/TN between black soil and paddy soil. The Lab-N of red soil under NPKS treatment decreased significantly compared with CK treatment, while the Lab-N of fluvo-aquic soil increased significantly. The TN, Lab-N and the Lab-N/TN in the upland soils under NPKM treatment increased significantly. And the black soil increased the most by 85.0%, 106.0% and 4.2%; there was no significant difference in the Lab-N and Lab-N/TN in the paddy soil between NPKM and CK treatments. Both the Rec-N and the TN in four soils under four different treatments were in the order of NPKM>NPKS>NPK>CK. The Rce-N/TN under NPKM decreased significantly compared with CK treatment. 【Conclusion】 Both the Lab-N and the Lab-N/TN in upland soils were more susceptible to fertilizer application compared with paddy soil. The TN, Lab-N and Lab-N/TN all increased significantly under NPKM treatment, and the improvement effect was in the order of NPKM>NPKS>NPK.
[本文引用: 1]
[本文引用: 1]
URL [本文引用: 1]
土壤有机碳是土壤质量变化的重要指标，土壤活性有机碳组分在土壤质量变化方面发挥重要作用。采用有机碳分组技术，研究了干旱荒漠区自然土壤开垦对绿洲农田土壤有机碳活性组分及团聚体稳定性的影响。结果表明：低有机碳含量的自然土壤垦殖后，有利于干旱荒漠区绿洲棉田土壤有机碳的积累，且垦殖（0-5a）增加显著，年均增加在0.65 g kg-1以上，上升幅度为76%-286%，5a后维持在相对平衡的水平；土壤活性有机碳、轻组有机碳在垦殖0-5a显著增加，平均增加72%和99%，5a后下降；颗粒有机碳则表现出垦殖0-10a明显增加，增加在275%以上，10a后下降；土壤水稳性团聚体含量随垦殖年限的延长显著增加，0-20a内较自然土壤提高了75%。垦殖可能是干旱区绿洲农田潜在碳汇的重要影响因素；但随垦殖年限延长，土壤有机碳活性组分下降，土壤质量又存在一定的退化风险。
URL [本文引用: 1]
土壤有机碳是土壤质量变化的重要指标，土壤活性有机碳组分在土壤质量变化方面发挥重要作用。采用有机碳分组技术，研究了干旱荒漠区自然土壤开垦对绿洲农田土壤有机碳活性组分及团聚体稳定性的影响。结果表明：低有机碳含量的自然土壤垦殖后，有利于干旱荒漠区绿洲棉田土壤有机碳的积累，且垦殖（0-5a）增加显著，年均增加在0.65 g kg-1以上，上升幅度为76%-286%，5a后维持在相对平衡的水平；土壤活性有机碳、轻组有机碳在垦殖0-5a显著增加，平均增加72%和99%，5a后下降；颗粒有机碳则表现出垦殖0-10a明显增加，增加在275%以上，10a后下降；土壤水稳性团聚体含量随垦殖年限的延长显著增加，0-20a内较自然土壤提高了75%。垦殖可能是干旱区绿洲农田潜在碳汇的重要影响因素；但随垦殖年限延长，土壤有机碳活性组分下降，土壤质量又存在一定的退化风险。
[本文引用: 1]
[本文引用: 1]
[本文引用: 1]
[本文引用: 1]
[本文引用: 1]
URL [本文引用: 1]
以新疆策勒绿洲近百年来不同开垦年限农田为研究对象,采用空间序列换算时间序列的方法,研究绿洲农田开垦过程中土壤有机碳和全氮密度、碳氮比(C/N)及速效氮含量的垂直变化特征,并探讨了农田土壤碳氮变化与作物产量的关系。结果表明:荒漠土壤开垦后,显著增加了表层土壤(0-20 cm)有机碳和全氮密度,随开垦年限延长对深层土壤(40-200 cm)有机碳密度也有一定的影响,如在开垦30 a左右时下降了36.4%,但在100 a左右时则增加了52.0%。耕层土壤C/N随开垦年限延长而明显增加,深层土壤除100 a农田外其它均有不同程度下降;不同土层C/N与速效氮含量呈负相关关系,仅在开垦初期(0-10 a)达到显著水平。不同年限农田的玉米产量存在显著差异,且和有机碳及全氮密度(0-200 cm)均呈显著正相关;棉花除100和10 a农田产量差异较小外,在其它农田间均达显著水平,但和有机碳及全氮密度无明显相关性。由此可见,在现有投入条件下,提高土壤碳氮累积量对增加玉米产量仍有十分重要作用,但对棉花产量的影响不明显。
URL [本文引用: 1]
以新疆策勒绿洲近百年来不同开垦年限农田为研究对象,采用空间序列换算时间序列的方法,研究绿洲农田开垦过程中土壤有机碳和全氮密度、碳氮比(C/N)及速效氮含量的垂直变化特征,并探讨了农田土壤碳氮变化与作物产量的关系。结果表明:荒漠土壤开垦后,显著增加了表层土壤(0-20 cm)有机碳和全氮密度,随开垦年限延长对深层土壤(40-200 cm)有机碳密度也有一定的影响,如在开垦30 a左右时下降了36.4%,但在100 a左右时则增加了52.0%。耕层土壤C/N随开垦年限延长而明显增加,深层土壤除100 a农田外其它均有不同程度下降;不同土层C/N与速效氮含量呈负相关关系,仅在开垦初期(0-10 a)达到显著水平。不同年限农田的玉米产量存在显著差异,且和有机碳及全氮密度(0-200 cm)均呈显著正相关;棉花除100和10 a农田产量差异较小外,在其它农田间均达显著水平,但和有机碳及全氮密度无明显相关性。由此可见,在现有投入条件下,提高土壤碳氮累积量对增加玉米产量仍有十分重要作用,但对棉花产量的影响不明显。
