岩溶区开荒退耕对土壤碳氮耦合关系的影响及作用机制

doi:10.13745/j.esf.sf.2024.11.76

地学前缘 ›› 2025, Vol. 32 ›› Issue (5): 524-533.DOI: 10.13745/j.esf.sf.2024.11.76

岩溶区开荒退耕对土壤碳氮耦合关系的影响及作用机制

吴泽燕¹^,²^,³(), 李强¹^,²^,³, 章程¹^,²^,³^,^*(), 蒋忠诚¹^,²^,³, 罗为群¹^,²^,³, 胡兆鑫¹^,²^,³, 涂纯¹^,²^,³

1.中国地质科学院岩溶地质研究所, 广西桂林 541004
2.广西平果喀斯特生态系统国家野外科学观测研究站/百色平果喀斯特生态系统野外科学观测研究站, 广西平果 531406
3.自然资源部、广西岩溶动力学重点实验室/联合国教科文组织国际岩溶研究中心, 广西桂林 541004

收稿日期:2024-07-02 修回日期:2024-12-02 出版日期:2025-09-25 发布日期:2025-10-14
通信作者: 章程
作者简介:吴泽燕(1990—),女,博士,助理研究员,从事岩溶退化生态系统碳氮循环。E-mail: wuzeyan@mail.cgs.gov.cn
基金资助:
广西科技基地和人才专项(桂科AD23026022);桂林市创新平台和人才计划项目(20220125-6);中国地质科学院岩溶地质研究所基本科研业务费项目(2023001);中国地质科学院岩溶地质研究所基本科研业务费项目(2023020);中国地质调查局地质调查项目(DD20230453)

The Impact and Mechanism of land reclamation and retirement on the coupling relationship between soil carbon and nitrogen in Karst areas

WU Zeyan¹^,²^,³(), LI Qiang¹^,²^,³, ZHANG Cheng¹^,²^,³^,^*(), JIANG Zhongcheng¹^,²^,³, LUO Weiqun¹^,²^,³, HU Zhaoxin¹^,²^,³, TU Chun¹^,²^,³

1. Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin 541004, China
2. Pingguo Guangxi, Karst Ecosystem, National Observation and Research Station/Pingguo Baise, Karst Ecosystem, Guangxi Observation and Research Station, Pingguo 531406, China
3. Key Laboratory of Karst Dynamics Ministry of Natural Resources, Guangxi/International Research Center on Karst under the Auspices of United Nations Educational, Scientific and Cultural Organization, Guilin 541004, China

Received:2024-07-02 Revised:2024-12-02 Online:2025-09-25 Published:2025-10-14
Contact: ZHANG Cheng

摘要/Abstract

摘要：

岩溶区生态恢复过程中,大部分退耕地具有深翻耕的开荒历史,但较少被关注,对是否引起土壤碳氮耦合关系变化的认识不足。本文在石漠化生态修复示范区内选择典型开荒退耕地,并以传统耕地作为对比,采集从地表到基岩的土壤样品共计39个,分析土壤有机碳(SOC)含量、全氮(TN)含量、土壤稳定同位素¹³C的自然丰度(δ¹³C_SOC)和碳氮比(C/N)。通过相关性分析和主成分分析研究土壤垂直剖面碳氮耦合关系及其作用机制。研究结果表明,传统耕地土壤剖面碳氮呈耦合变化,主要受植被源碳输入和微生物分解碳的程度调控,随着土壤深度增加,植被源碳氮输入逐渐减少,微生物碳分解活动受碳氮供应不足限制(即“碳氮限制”),符合一般规律。相比之下,开荒退耕地SOC含量和TN含量均值分别为2.23%±0.33%和0.25%±0.03%,分别比耕地高出74.2%和66.7%。SOC与TN含量不具相关性,且δ¹³C_SOC与SOC之间为正相关,呈现明显的碳氮“解耦合”特征。主要原因是开荒导致表层与深层土壤置换,原深层贫氮土壤在表层得到大气氮沉降和岩石氮额外补充,原表层富氮土壤又补充了深层土壤氮,解除了“氮限制”;原表层富碳土壤埋藏在深部(45~65 cm)后分解速率降低,解除了“碳限制”。本文研究成果丰富了岩溶土壤碳氮耦合关系理论,为生态修复下的岩溶石山区碳氮分布格局和存储评价等提供重要参考。

关键词: 岩溶, 开荒退耕, 土壤有机碳, 总氮, 土壤有机碳稳定碳同位素, 碳氮比

Abstract:

During the process of ecological restoration in karst areas, most of the retired croplands were reclaimed in the past and subjected to deep tillage. But this has received relatively little attention, and there is a lack of understanding of whether it causes changes in the soil carbon-nitrogen coupling relationship. In this paper, typical reclaimed croplands were selected within the demonstration area for ecological restoration of rocky desertification, with traditional croplands as a comparison. A total of 39 soil samples were collected from the surface to the bedrock, and the soil organic carbon content (SOC), total nitrogen content (TN), the natural abundance of soil stable isotope ¹³C (δ¹³C_SOC), and the carbon-to-nitrogen ratio (C/N) were analyzed. Correlation analysis and principal component analysis were used to study the soil carbon-nitrogen coupling relationship and its mechanism. The study shows that the soil carbon and nitrogen of traditional croplands exhibit coupled changes, mainly regulated by the input of vegetation-derived carbon and the degree of microbial decomposition of carbon. As soil depth increases, the input of carbon and nitrogen from vegetation sources gradually decreases, and microbial carbon decomposition activities are limited by the insufficient supply of carbon and nitrogen (known as “carbon-nitrogen limitation”). This is consistent with general patterns. In contrast, the mean contents of SOC and TN in the reclaimed slope croplands were 2.23%±0.33% and 0.25%±0.03%, respectively, which were 74.2% and 66.7% higher than those in the traditional croplands. There was no correlation between SOC and TN contents, and a positive correlation between δ¹³C_SOC and SOC, showing a clear “decoupling” characteristic of soil carbon and nitrogen. The main reason is that land reclamation led to the replacement of surface and deep soils. Deep, originally nitrogen-poor soils receive additional atmospheric nitrogen deposition and nitrogen from rocks in the surface layer, while the originally nitrogen-rich surface soils replenish the nitrogen in the deeper soils. This lifted the “nitrogen limitation”. And the decomposition rate of the originally carbon-rich surface soil decreases after being buried at a depth of 45 to 65cm, lifting the “carbon limitation”. These findings of this study enrich the theory of soil carbon-nitrogen coupling in karst areas and provide an important reference for the evaluation of carbon and nitrogen distribution and storage under ecological restoration in karst rocky mountainous areas.

Key words: Karst, land reclamation and conversion, soil organic carbon, total nitrogen, ¹³C stable isotope, C/N

中图分类号:

吴泽燕, 李强, 章程, 蒋忠诚, 罗为群, 胡兆鑫, 涂纯. 岩溶区开荒退耕对土壤碳氮耦合关系的影响及作用机制[J]. 地学前缘, 2025, 32(5): 524-533.

WU Zeyan, LI Qiang, ZHANG Cheng, JIANG Zhongcheng, LUO Weiqun, HU Zhaoxin, TU Chun. The Impact and Mechanism of land reclamation and retirement on the coupling relationship between soil carbon and nitrogen in Karst areas[J]. Earth Science Frontiers, 2025, 32(5): 524-533.

图/表 10

图1 研究区采样点示意图

Fig.1 Distribution of soil sampling sites in the study area

表1 RRF与CF样地土壤剖面碳氮指标统计值

Table 1 Statistics of carbon and nitrogen indicators in RRF and CF soil profile

样地	指标	最大值	最小值	平均值	标准差	变异系数^*
RRF	SOC含量/%	2.71	1.51	2.23	0.33	0.15
	δ¹³C_SOC值/‰	-16.14	-20.28	-18.50	1.30	-0.07
	TN含量/%	0.30	0.21	0.25	0.03	0.15
	C/N值	13.14	6.86	8.85	1.66	0.19
CF	SOC含量/%	1.92	0.96	1.28	0.22	0.17
	δ¹³C_SOC值/‰	-15.87	-20.83	-17.84	1.42	-0.08
	TN含量/%	0.22	0.11	0.15	0.03	0.11
	C/N值	11.04	6.71	8.40	1.37	0.16

表2 RRF样地土壤剖面碳氮指标相关性

Table 2 Correlation between carbon and nitrogen indicators in RRF soil profile

指标	SOC含量	TN含量	δ¹³C_SOC值	C/N值
SOC含量	1
TN含量	0.190	1
δ¹³C_SOC值	0.563^*	-0.254	1
C/N值	0.739^**	-0.506^*	0.619^*	1

表3 CF样地土壤剖面碳氮指标相关性分析

Table 3 Correlation between carbon and nitrogen indicators in CF soil profile

指标	SOC含量	TN含量	δ¹³C_SOC值	C/N值
SOC含量	1
TN含量	0.642^**	1
δ¹³C_SOC值	-0.486^*	-0.944^**	1
C/N值	0.251	-0.569^*	0.685^**	1

图2 CF样地土壤剖面各个碳氮指标变化曲线

Fig.2 Curves of various carbon and nitrogen indicators in the soil profile of CF sites

图3 CF样地两个主成分的因子载荷和样本得分 a—4个因子两个主成分上的载荷,绝对值越大,说明解释度越大;b—各个深度样本主成分得分。

Fig.3 Factor loading of two principal components and sample scores of CF site

图4 CF样地土壤剖面SOC含量、δ13CSOC值和TN含量散点图 a—CF样地SOC含量与δ13CSOC值的拟合;b—CF样地SOC含量与TN含量的拟合;c—CF样地TN含量与δ13CSOC值的拟合。

Fig.4 Scatter plot of soil SOC,δ13CSOC, and TN in CF site

图5 RRF样两个主成分的因子载荷和样本得分 a—4个因子在两个主成分上的载荷,绝对值越大,说明解释度越大;b—各个深度样本主成分得分。

Fig.5 Factor loading of two principal components and sample scores of RRF site

图6 RRF样地土壤剖面各个碳氮指标变化曲线

Fig.6 Curves of various carbon and nitrogen indicators in the soil profile of RRF plot

图7 RRF样地土壤剖面SOC含量、δ13CSOC值和TN含量散点图 a—RRF样地SOC含量与δ13CSOC值不存在拟合关系;b—RRF样地SOC含量与TN含量不存在拟合关系;c—RRF样地TN含量与δ13CSOC值不存在拟合关系。

Fig.7 Scatter plot of soil SOC,δ13CSOC, and TN in RRF site

参考文献 36

[1]	WANG J X, LAN J C, LONG Q X, et al. Soil organic carbon transfer in aggregates subjected to afforestation in Karst region as indicated by ¹³C natural abundance[J]. Forest Ecology and Management, 2023, 531: 120798.
[2]	YU P J, LI Y X, LIU S W, et al. Afforestation influences soil organic carbon and its fractions associated with aggregates in a Karst region of Southwest China[J]. Science of the Total Environment, 2022, 814: 152710.
[3]	李发东, 栗照鑫, 乔云峰, 等. 土壤有机碳同位素组成在农田生态系统碳循环中的应用进展[J]. 中国生态农业学报(中英文), 2023, 31(2): 194-205.
[4]	HU P L, LIU S J, YE Y Y, et al. Soil carbon and nitrogen accumulation following agricultural abandonment in a subtropical Karst region[J]. Applied Soil Ecology, 2018, 132: 169-178.
[5]	QIN C Q, LI S L, YU G H, et al. Vertical variations of soil carbon under different land uses in a Karst critical zone observatory (CZO), SW China[J]. Geoderma, 2022, 412: 115741.
[6]	LAN J C, HU N, FU W L. Soil carbon-nitrogen coupled accumulation following the natural vegetation restoration of abandoned farmlands in a Karst rocky desertification region[J]. Ecological Engineering, 2020, 158: 106033.
[7]	LI S L, LIU C Q, CHEN J N, et al. Karst ecosystem and environment: characteristics, evolution processes, and sustainable development[J]. Agriculture, Ecosystems & Environment, 2021, 306: 107173.
[8]	JIANG Z C, LIAN Y Q, QIN X Q. Rocky desertification in Southwest China: impacts, causes, and restoration[J]. Earth-Science Reviews, 2014, 132: 1-12.
[9]	蒋忠诚, 罗为群, 童立强, 等. 21世纪西南岩溶石漠化演变特点及影响因素[J]. 中国岩溶, 2016, 35(5): 461-468.
[10]	YUE Y M, QI X K, WANG K L, et al. Large scale rocky desertification reversal in South China Karst[J]. Progress in Physical Geography: Earth and Environment, 2022, 46(5): 661-675.
[11]	LV Y, ZHANG L, LI P, et al. Ecological restoration projects enhanced terrestrial carbon sequestration in the Karst region of Southwest China[J]. Frontiers in Ecology and Evolution, 2023, 11: 1179608.
[12]	SCHIEDUNG M, TREGURTHA C S, BEARE M H, et al. Deep soil flipping increases carbon stocks of New Zealand grasslands[J]. Global Change Biology, 2019, 25(7): 2296-2309.
[13]	ALCÁNTARA V, DON A, WELL R, et al. Deepploughing increases agricultural soil organic matter stocks[J]. Global Change Biology, 2016, 22(8): 2939-2956.
[14]	KIRSCHBAUM M U F, DON A, BEARE M H, et al. Sequestration of soil carbon by burying it deeper within the profile: a theoretical exploration of three possible mechanisms[J]. Soil Biology and Biochemistry, 2021, 163: 108432.
[15]	BURGER D J, SCHNEIDER F, BAUKE S L, et al. Fifty years after deep-ploughing: effects on yield, roots, nutrient stocks and soil structure[J]. European Journal of Soil Science, 2023, 74(6): e13426.
[16]	刘娅. 喀斯特小流域土壤碳氮耦合与沉积有机质来源研究[D]. 贵阳: 贵州师范大学, 2023.
[17]	HAN G L, TANG Y, LIU M, et al. Carbon-nitrogen isotope coupling of soil organic matter in a Karst region under land use change, Southwest China[J]. Agriculture, Ecosystems & Environment, 2020, 301: 107027.
[18]	POAGE M A, FENG X H. A theoretical analysis of steady state δ¹³C profiles of soil organic matter[J]. Global Biogeochemical Cycles, 2004, 18(2): GB2016.
[19]	景建生, 刘子琦, 罗鼎, 等. 喀斯特洼地土壤有机碳分布特征及影响因素[J]. 森林与环境学报, 2020, 40(2): 133-139.
[20]	ABDALLA K, MUTEMA M, HILL T. Soil and organic carbon losses from varying land uses: a global meta-analysis[J]. Geographical Research, 2020, 58(2): 167-185.
[21]	LI C F, WANG Z C, LI Z W, et al. Soil erosion impacts on nutrient deposition in a typical Karst watershed[J]. Agriculture, Ecosystems & Environment, 2021, 322: 107649.
[22]	李强. 岩溶土壤有机碳库分配、更新及其维持的微生物机制[J]. 微生物学报, 2022, 62(6): 2188-2197.
[23]	PUENTE M E, LI C Y, BASHAN Y. Rock-degrading endophytic bacteria in cacti[J]. Environmental and Experimental Botany, 2009, 66(3): 389-401.
[24]	LOPEZ-LOZANO N E, CARCAÑO-MONTIEL M G, BASHAN Y. Using native trees and cacti to improve soil potential nitrogen fixation during long-term restoration of arid lands[J]. Plant and Soil, 2016, 403(1): 317-329.
[25]	PIOTROWSKA-DŁUGOSZ A, DŁUGOSZ J, FRĄC M, et al. Enzymatic activity and functional diversity of soil microorganisms along the soil profile: a matter of soil depth and soil-forming processes[J]. Geoderma, 2022, 416: 115779.
[26]	LIAO C, CHANG K K, WU B Y, et al. Divergence in soil particulate and mineral-associated organic carbon reshapes carbon stabilization along an elevational gradient[J]. Catena, 2024, 235: 107682.
[27]	HICKS PRIES C E, RYALS R, ZHU B, et al. The deep soil organic carbon response to global change[J]. Annual Review of Ecology, Evolution, and Systematics, 2023, 54: 375-401.
[28]	崔雅如, 牟长城, 姬文慧, 等. 长白山月亮湾亚高山湿地生态系统碳氮储量沿水分梯度空间分异规律及机制[J]. 生态学报, 2024, 44(18): 7977-7990.
[29]	MAYER S, KÜHNEL A, BURMEISTER J, et al. Controlling factors of organic carbon stocks in agricultural topsoils and subsoils of Bavaria[J]. Soil and Tillage Research, 2019, 192: 22-32.
[30]	ALCÁNTARA V, DON A, VESTERDAL L, et al. Stability of buried carbon in deep-ploughed forest and cropland soils: implications for carbon stocks[J]. Scientific Reports, 2017, 7(1): 5511.
[31]	CHAOPRICHA N T, MARÍN-SPIOTTA E. Soil burial contributes to deep soil organic carbon storage[J]. Soil Biology and Biochemistry, 2014, 69: 251-264.
[32]	HICKS PRIES C E, SULMAN B N, WEST C, et al. Root litter decomposition slows with soil depth[J]. Soil Biology and Biochemistry, 2018, 125: 103-114.
[33]	KRÜGER N, FINN D R, DON A. Soil depth gradients of organic carbon-13: a review on drivers and processes[J]. Plant and Soil, 2024, 495(1): 113-136.
[34]	HU L N, LI Q, YAN J H, et al. Vegetation restoration facilitates below ground microbial network complexity and recalcitrant soil organic carbon storage in Southwest China Karst region[J]. Science of the Total Environment, 2022, 820: 153137.
[35]	HOULTON B Z, MORFORD S L, DAHLGREN R A. Convergent evidence for widespread rock nitrogen sources in Earth’s surface environment[J]. Science, 2018, 360(6384): 58-62.
[36]	MORFORD S L, HOULTON B Z, DAHLGREN R A. Direct quantification of long-term rock nitrogen inputs to temperate forest ecosystems[J]. Ecology, 2016, 97(1): 54-64.

岩溶区开荒退耕对土壤碳氮耦合关系的影响及作用机制

The Impact and Mechanism of land reclamation and retirement on the coupling relationship between soil carbon and nitrogen in Karst areas

RichHTML

PDF (PC)

可视化

摘要/Abstract

引用本文

使用本文

图/表 10

参考文献 36

相关文章 15

编辑推荐

Metrics

本文评价

[1]	陈伟志, 陶兰初, 李静婷, 张亚, 巴永, 宋琳. 高原湿地纳帕海流域地表水水化学特征及控制因素[J]. 地学前缘, 2025, 32(5): 493-510.
[2]	杨德彬, 高济元, 张恒, 蔡忠贤, 吕艳萍, 张娟, 汪彦. 塔里木盆地塔河油田奥陶系大型岩溶暗河类型、发育特征及其形成条件[J]. 地学前缘, 2025, 32(4): 483-496.
[3]	李凤磊, 林承焰, 王蛟, 任丽华, 张国印, 朱永峰, 李世银, 张银涛, 关宝珠. 超深层断缝带岩溶缝洞体储层结构分析与智能预测[J]. 地学前缘, 2025, 32(2): 311-331.
[4]	马海陇, 杨德彬, 王震, 张娟, 巫波, 张世亮, 袁飞宇. 塔河油田走滑断裂与古岩溶耦合关系研究及其对奥陶系储层发育的影响[J]. 地学前缘, 2024, 31(5): 227-246.
[5]	曹建华, 杨慧, 黄芬, 张春来, 张连凯, 朱同彬, 周孟霞, 袁道先. 岩溶碳汇原理、过程与计量[J]. 地学前缘, 2024, 31(5): 358-376.
[6]	张春来, 杨慧, 黄芬, 邱成, 朱同彬. 亚热带季风区边缘坡立谷河流水化学特征及外源水的增汇效应:以广西马山县清波河流域为例[J]. 地学前缘, 2024, 31(5): 377-386.
[7]	黄思宇, 蒲俊兵, 潘谋成, 李建鸿, 张陶. 岩溶水库藻源性有机质来源对表层沉积物有机碳矿化过程的影响[J]. 地学前缘, 2024, 31(5): 387-396.
[8]	吴庆, 黄芬, 郭永丽, 肖琼, 孙平安, 杨慧, 白冰. 西南岩溶小流域水体中微量元素地球化学特征及其指示意义[J]. 地学前缘, 2024, 31(5): 397-408.
[9]	孙彩云, 郑冰清, 李俊, 符洪铭, 孙荣卿, 刘红豪, 廖祖莹, 江红生, 吴振斌, 夏世斌, 王培. 沉水植物对岩溶碳汇稳定性影响研究[J]. 地学前缘, 2024, 31(5): 430-439.
[10]	李凤磊, 林承焰, 任丽华, 张国印, 关宝珠. 塔里木盆地塔北地区多期断裂差异匹配控制下超深岩溶缝洞储层成藏特征[J]. 地学前缘, 2024, 31(4): 219-236.
[11]	吕良华, 王水. 耦合CO₂脱气的岩溶地热水结垢趋势定量分析[J]. 地学前缘, 2024, 31(3): 402-409.
[12]	金燕林, 张慧涛, 刘遥, 吉玉雯. 塔河油田层控岩溶型储集体发育特征及典型岩溶模式探讨[J]. 地学前缘, 2023, 30(6): 125-134.
[13]	鲁鹏达, 李泽奇, 田腾振, 吴娟, 孙玮, 乔占峰, 王永生, 刘树根, 邓宾. 四川盆地震旦系灯影组二段葡萄-花边结构成因及其对储层控制作用[J]. 地学前缘, 2023, 30(6): 14-31.
[14]	李毕松, 金民东, 朱祥, 代林呈, 杨毅. 川东北地区灯四段储层成岩作用及孔隙演化[J]. 地学前缘, 2023, 30(6): 32-44.
[15]	尤东华, 彭守涛, 何治亮, 刘永立, 韩俊, 肖重阳, 李映涛. 塔里木盆地阿-满过渡带北部深循环岩溶作用的范围与机制[J]. 地学前缘, 2023, 30(6): 69-79.