Influence mechanism of calcium on soil organic nitrogen mineralization during calcareous soil evolvement in karst areas
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摘要: 选择桂林岩溶区不同演化阶段典型的黑色、棕色和红色石灰土为研究对象,采用改进的BCR方法测定石灰土不同钙形态含量,通过15N同位素标记技术结合MCMC氮素转化模型测定石灰土总有机氮矿化(MNorg)、易分解有机氮矿化(MNlab)和难分解有机氮矿化(MNrec)速率,探讨了岩溶区石灰土演化过程中钙影响土壤氮矿化的机制。结果表明:(1)岩溶区黑色和棕色石灰土各形态钙含量顺序均为交换态(ECa)>酸溶态(ASCa)>残渣态(RCa)>水溶态(WSCa)>有机结合态(OCCa),红色石灰土各形态钙含量大小顺序为ECa>RCa>ASCa>WSCa>OCCa,石灰土不同形态钙中以ECa含量最多,分别占黑色、棕色和红色石灰土全钙含量的80%、64%和48%,表明钙在石灰土中具有较高的活度;(2)MNorg和MNrec大小顺序均为黑色石灰土>棕色石灰土>红色石灰土,MNlab大小顺序为黑色石灰土<棕色石灰土<红色石灰土,黑色石灰土MNorg由MNrec主导,棕色和红色石灰土MNorg主要由MNlab控制,说明石灰土演化影响土壤有机氮的矿化过程,降低土壤无机氮供应能力;(3)除MNorg、MNlab和MNrec与OCCa和RCa的相关性不显著外,MNorg和MNrec分别与ECa、ASCa和WSCa含量呈显著正相关,MNlab则与之呈显著负相关,表明高含量有效态钙能促进土壤MNrec而抑制MNlab。ECa和ASCa作为石灰土钙的主要赋存形态因在土壤演化过程中受到强烈淋溶作用,促使MNrec显著降低,这是造成石灰土演化过程中土壤无机氮供应能力显著降低的重要原因。研究结果有助于更清晰地了解石灰土演化过程中钙的分布、迁移和氮矿化特征以及钙对氮矿化过程的影响,为深入理解岩溶区石灰土氮矿化过程的影响机制提供理论依据。Abstract:
Nitrogen (N) is an essential nutrient element for the normal growth and development of plants, and the major factor affecting the primary productivity of most terrestrial ecosystems. Studying the process of soil organic N mineralization on the basis of regional characteristics is of great significance for formulating reasonable fertilization measures, and optimizing soil environment and global N cycling. Karst is a unique ecological system restricted by N. In order to discuss the influence mechanism of calcium (Ca) in soil organic N mineralization during calcareous soil evolvement in karst areas, the typical black calcareous soil (BLCS), brown calcareous soil (BRCS) and red calcareous soil (RCS) at different soil evolvement stages in the karst areas in Guilin were selected as research objects. The BCR three-step sequential extraction procedure was used to determine Ca contents of different species, and the 15N tracing technology combined with the Markov Chain Monte Carlo (MCMC) algorithm-based numerical optimization model were adopted to investigate the mineralization of labile organic N (MNlab), recalcitrant organic N (MNrec) and organic N (MNorg) to NH$_4^{+}$ in calcareous soil. The results showed as follows: (1) The orders of the contents of Ca species of BLCS and BRCS were both listed as exchangeable Ca (ECa) > acid soluble Ca (ASCa) > residual Ca (RCa) > water soluble Ca (WSCa) > organic compound Ca (OCCa); the order of the contents of Ca species of RCS was: ECa > RCa > ASCa > WSCa > OCCa. The contents of ECa were the highest among the different species of Ca in BLCS, BRCS and RCS in karst areas, repectively accounting for 80%, 64% and 48% of the total Ca contents of these three calcareous soils, showing that Ca in calcareous soil presents high activity. (2) MNorg and MNrec of these three calcareous soils were listed as the following order: BLCS > BRCS > RCS; the order of MNlab: BLCS < BRCS < RCS. MNorg was dominated by MNrec in BLCS, while MNorg was mainly controlled by MNlab in both BRCS and RCS, showing that calcareous soil evolvement affected the mineralization process of soil organic N, and the soil inorganic N supply capacity decreased significantly during calcareous soil evolvement in karst areas. (3) Except the insignificant correlation between soil MNorg, MNlab and MNrec, and OCCa and RCa, MNorg and MNrec presented significantly positive correlation with the contents of ECa, ASCa and WSCa, respectively, while MNlab presented significantly negative correlation with these variables, which indicates that high contents of available Ca can promote MNrec but inhibit MNlab. As the main species of Ca in calcareous soil, ECa and ASCa were strongly leached during calcareous soil evolvement in karst areas, resulting in the significant decrease of soil MNrec, which was an important reason for the significant decrease of soil inorganic N supply capacity during calcareous soil evolvement. The study results will help us to clearly understand the characteristics of the distribution and migration of Ca, N mineralization and effect of Ca on N mineralization during calcareous soil evolvement in karst areas, and may provide the basic data for deep understanding of the influence mechanism of N mineralization process in calcareous soil. With the evolvement of calcareous soil, calcareous soil with high degree of evolvement in karst areas, such as BRCS and RCS, may be unfavorable for maintaining soil fertility and natural vegetation restoration due to low inorganic N supply capacity. Therefore, in the process of ecological restoration, for the karst areas with high degree of calcareous soil evolvement such as BRCS and RCS, improving the N content of calcareous soil can promote the effective supply of inorganic N in calcareous soil to create a soil environment conducive to vegetation restoration. This may be an effective strategy for rapid restoration of karst ecosystems. -
Key words:
- mineralization rate /
- soil calcium species /
- 15N tracing technology /
- calcareous soil /
- karst area
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图 2 石灰土不同演化阶段有机氮矿化速率
(图中小写字母表示不同石灰土难分解有机氮矿化间的差异达显著水平(P<0.05),不同大写字母表示不同石灰土易分解有机氮矿化间的差异达显著水平(P<0.05))
Figure 2. Nitrogen mineralization rates in soil at different stages of calcareous soil evolvement
(In the figure, different lowercase letters indicate significant differences in MNrec in different calcareous soils (P<0.05), and different uppercase letters indicate significant differences in MNlab in different calcareous soils (P<0.05)).
表 1 岩溶区石灰土不同演化阶段钙不同形态含量
Table 1. Contents of Ca species in soil at different stages of calcareous soil evolvement in karst areas
黑色石灰土 棕色石灰土 红色石灰土 水溶态钙(×10−3) 0.24±0.04a 0.14±0.04b 0.05±0.03c 交换态钙(×10−3) 20.4±3.72a 4.87±0.63b 1.34±0.09c 酸溶态钙(×10−3) 3.95±0.87a 1.25±0.65b 0.37±0.20b 有机结合态钙(×10−3) 0.14±0.07a 0.09±0.03a 0.04±0.01a 残渣态钙(×10−3) 0.88±0.12b 1.21±0.24a 0.99±0.01ab 全钙(×10−3) 25.7±4.50a 7.56±0.72b 2.79±0.24b 注:同行中不同字母表示同一指标差异达显著水平(p<0.05),数值表示平均值±标准偏差。
Note: Different letters in the same line indicate a significant level of difference in the same index (p<0.05), and the value represents the mean ± standard deviation.表 2 石灰土不同钙形态含量与总有机氮矿化(MNorg)、难分解有机氮矿化(MNrec)和易分解有机氮矿化(MNlab)速率的相关性
Table 2. Correlation coefficients between the mineralization rates of MNorg, MNrec and MNlab, and calcium species contents in calcareous soil
MNrec MNlab MNorg 水溶态钙 0.85** −0.68* 0.83** 交换态钙 0.94** −0.78** 0.92* 酸溶态钙 0.93** −0.85** 0.88** 有机结合态钙 0.50 −0.45 0.48 残渣态钙 −0.49 0.30 −0.52 全钙 0.94** −0.80** 0.91* 注:样本数n =9, *表示相关性达到P<0.05 显著水平,**表示相关性达到P<0.01 显著水平。
Note: Sample size n=9; * represents a significant correlation (P<0.05); ** represents a significant correlation (P<0.01). -
[1] Booth M S, Stark J M, Rastetter E. Controls on nitrogen cycling in terrestrial ecosystems: A synthetic analysis of literature data[J]. Ecological Monographs, 2005, 75(2): 139-157. doi: 10.1890/04-0988 [2] Yuan Daoxian. Karst of China[M]. Beijing: Geological Publishing House, 1991. [3] 胡宁, 马志敏, 蓝家程, 伍宇春, 陈高起, 傅瓦利, 文志林, 王文净. 石漠化山地植被恢复过程土壤团聚体氮分布及与氮素矿化关系研究[J]. 环境科学, 2015, 36(9):3411-3421.HU Ning, MA Zhimin, LAN Jiacheng, WU Yuchun, CHEN Gaoqi, FU Wali, WEN Zhilin, WANG Wenjing. Nitrogen fraction distributions and impacts on soil nitrogen mineralization in different vegetation restorations of karst rocky desertification[J]. Environmental Science, 2015, 36(9): 3411-3421. [4] 杨怡, 欧阳运东, 陈浩, 肖孔操, 李德军. 西南喀斯特区植被恢复对土壤氮素转化通路的影响[J]. 环境科学, 2018, 39(6):2845-2852.YANG Yi, OUYANG Yundong, CHEN Hao, XIAO Kongcao, LI Dejun. Effects of vegetation restoration on soil nitrogen pathways in a karst region of Southwest China[J]. Environmental Science, 2018, 39(6): 2845-2852. [5] Zhu Tongbin, Zeng Siman, Qin Hanlian, Zhou Kexin, Yang Hui, Lan Funing, Huang Fen, Cao Jianhua, Christoph Müller. Low nitrate retention capacity in calcareous soil under woodland in the karst region of Southwestern China[J]. Soil Biology and Biochemistry, 2016, 97: 99-101. doi: 10.1016/j.soilbio.2016.03.001 [6] Li Dejun, Yang Yi, Chen Hao, Xiao Kongcao, Song Tongqing, Wang Kelin. Soil gross nitrogen transformations in typical karst and nonkarst forests, Southwest China[J]. Journal of Geophysical Research: Biogeosciences, 2017, 122(11): 2831-2840. doi: 10.1002/2017JG003850 [7] 曾四满, 刘满强, 陈小云, 朱同彬, 曹建华, Christoph Müller. 岩溶区和碎屑岩区林地和农田土壤氮矿化过程对比研究[J]. 中国岩溶, 2016, 35(3):269-273.ZENG Siman, LIU Manqiang, CHEN Xiaoyun, ZHU Tongbin, CAO Jianhua, Christoph Müller. Comparative study on nitrogen mineralization of soil in woodland and cropland in karst and clasolite regions[J]. Carsologica Sinica, 2016, 35(3): 269-273. [8] 赖倩倩, 杨霖, 秦兴华, 田伟, 伍延正, 汤水荣, 解钰, Christoph Müller, 孟磊. 蔗渣生物质炭对喀斯特农田石灰性土壤氮转化过程的短期影响[J]. 中国岩溶, 2019, 38(3):450-457.LAI Qianqian, YANG Lin, QIN Xinghua, TIAN Wei, WU Yanzheng, TANG Shuirong, XIE Yu, Christoph Müller, MENG Lei. Study on short-term effects of sugarcane biochar on nitrogen transformation in calcareous soils in karst farmland[J]. Carsologica Sinica, 2019, 38(3): 450-457. [9] Song Min, He Tieguagn, Chen Hao, Wang Kelin, Li Dejun. Dynamics of soil gross nitrogen transformations during post-agricultural succession in a subtropical karst region[J]. Geoderma, 2019, 341: 1-9. doi: 10.1016/j.geoderma.2019.01.034 [10] Li Dejun, Liu Jing, Chen Hao, Zheng Liang, Wang Kelin. Soil gross nitrogen transformations in responses to land use conversion in a subtropical karst region[J]. Journal of Environmental Management, 2018, 212: 1-7. [11] 杨会, 朱同彬, 吴夏, 郝玉培, 吴华英. 岩溶区种植砂糖桔对石灰土有机氮矿化过程的影响[J]. 南方农业学报, 2020, 51(11):2665-2673. doi: 10.3969/j.issn.2095-1191.2020.11.008YANG Hui, ZHU Tongbin, WU Xia, HAO Yupei, WU Huaying. Effects of sugar orange plantation on organic nitrogen mineralization in different calcareous soils in karst region[J]. Journal of Southern Agriculture, 2020, 51(11): 2665-2673. doi: 10.3969/j.issn.2095-1191.2020.11.008 [12] 文冬妮, 杨程, 杨霖, 秦兴华, 孟磊, 何秋香, 朱同彬, Christoph Müller. 岩溶区农业种植对土壤有机氮矿化的影响[J]. 中国岩溶, 2020, 39(2):189-195.WEN Dongni, YANG Cheng, YANG Lin, QIN Xinghua, MENG Lei, HE Qiuxiang, ZHU Tongbin, Christoph Müller. Effects of agricultural cultivation on soil organic nitrogen mineralization in karst regions[J]. Carsologica Sinica, 2020, 39(2): 189-195. [13] 曹建华, 袁道先, 潘根兴. 岩溶生态系统中的土壤[J]. 地球科学进展, 2003, 18(1):37-44. doi: 10.3321/j.issn:1001-8166.2003.01.006CAO Jianhua, YUAN Daoxian, PAN Genxing. Some soil features in karst ecosystem[J]. Advances in Earth Science, 2003, 18(1): 37-44. doi: 10.3321/j.issn:1001-8166.2003.01.006 [14] 曹建华, 袁道先, 章程, 蒋忠诚. 受地质条件制约的中国西南岩溶生态系统[J]. 地球与环境, 2004, 32(1):1-8.CAO Jianhua, YUAN Daoxian, ZHANG Cheng, JIANG Zhongcheng. Karst ecosystem constrained by geological conditions in Southwest China[J]. Earth and Environment, 2004, 32(1): 1-8. [15] 张美良, 邓自强. 我国南方喀斯特地区的土壤及其形成[J]. 贵州工学院学报, 1994, 23(1):67-75.ZHANG Meiliang, DENG Ziqiang. The soil and soil-forming processes in karst area of South China[J]. Journal of Guizhou Institute of Technology, 1994, 23(1): 67-75. [16] 胡乐宁, 苏以荣, 何寻阳, 李扬, 黎蕾, 王媛华, 吴金水. 西南喀斯特石灰土中钙的形态与含量及其对土壤有机碳的影响[J]. 中国农业科学, 2012, 45(10):1946-1953. doi: 10.3864/j.issn.0578-1752.2012.10.007HU Lening, SU Yirong, HE Xunyang, LI Yang, LI Lei, WANG Yuanghua, WU Jinshui. The speciation and content of calcium in karst soils, and its effects on soil organic carbon in karst region of Southwest China[J]. Scientia Agricultura Sinica, 2012, 45(10): 1946-1953. doi: 10.3864/j.issn.0578-1752.2012.10.007 [17] 陈家瑞, 曹建华, 梁毅, 杨慧. 石灰土发育过程中土壤腐殖质组成及其与土壤钙赋存形态关系[J]. 中国岩溶, 2012, 31(1):7-11.CHEN Jiarui, CAO Jianhua, LIANG Yi, YANG Hui. Relationship of the humus components and the calcium form with the development of limestone soil[J]. Carsologica Sinica, 2012, 31(1): 7-11. [18] 梁建宏, 曹建华, 杨慧, 黄芬. 钙、铁、铝形态对岩溶石灰土磷有效性的影响[J]. 中国岩溶, 2016, 35(2):211-217. doi: 10.11932/karst20160211LIANG Jianhong, CAO Jianhua, YANG Hui, HUANG Fen. Effects of calcium, iron and aluminum fractions on the phosphorus bioavailability in limestone soil of karst region[J]. Carsologica Sinica, 2016, 35(2): 211-217. doi: 10.11932/karst20160211 [19] 余海, 王世杰. 土壤中钙形态的连续浸提方法[J]. 岩矿测试, 2007, 26(6):436-440.YU Hai, WANG Shijie. A new sequential extraction of calcium species in soil samples[J]. Rock and Mineral Analysis, 2007, 26(6): 436-440. [20] Bremner J M, Keeney D R. Determination and isotope-ratio analysis of different forms of nitrogen in soils: 3. Exchangeable ammonium, nitrate, and nitrite by extraction-distillation methods[J]. Soil Science Society of America Journal, 1966, 30(5): 577-582. doi: 10.2136/sssaj1966.03615995003000050015x [21] Müller C, Rütting T, Kattge J, Laughlin R J, Stevens R J. Estimation of parameters in complex 15N tracing models by Monte Carlo sampling[J]. Soil Biology and Biochemistry, 2007, 39(3): 715-726. doi: 10.1016/j.soilbio.2006.09.021 [22] Xie Yu, Yang Lin, Zhu Tongbin, Yang Hui, Zhang Jianbing, Yang Jinling, Cao Jianhua, Bai Bing, Jiang Zhongcheng, Liang Yueming, Lan Funing, Meng Lei, ChristophMüller. Rapid recovery of nitrogen retention capacity in a subtropical acidic soil following afforestation[J]. Soil Biology and Biochemistry, 2018, 120: 171-180. doi: 10.1016/j.soilbio.2018.02.008 [23] 宋照亮, 刘丛强, 彭渤, 杨成. 逐级提取(SEE)技术及其在沉积物和土壤元素形态研究中的应用[J]. 地球与环境, 2004, 32(2):70-77. doi: 10.3969/j.issn.1672-9250.2004.02.014SONG Zhaoliang, LIU Congqiang, PENG Bo, YANG Cheng. Sequential extraction (SEE) technology and its applications to sediment and soil element speciation studies[J]. Earth and Environment, 2004, 32(2): 70-77. doi: 10.3969/j.issn.1672-9250.2004.02.014 [24] 杨慧, 陈家瑞, 梁建宏, 曹建华. 桂林丫吉岩溶区土壤有机碳和pH值与钙形态分布的关系初探[J]. 地质论评, 2017, 63(4):1117-1126.YANG Hui, CHEN Jiarui, LIANG Jianhong, CAO Jianhua. Preliminary study on the relationship between soil organic carbon and pH value and calcium species in Yaji karst region, Guilin[J]. Geological Review, 2017, 63(4): 1117-1126. [25] Dahlqvist R, Benedetti M F, Andersson K, Turner D, Larsson T, Stolpe B, Ingri J. Association of calcium with colloidal particles and speciation of calcium in the Kalix and Amazon rivers[J]. Geochimica et Cosmochimica Acta, 2004, 68(20): 4059-4075. doi: 10.1016/j.gca.2004.04.007 [26] 蒋忠诚. 中国南方表层岩溶系统的碳循环及其生态效应[J]. 第四纪研究, 2000, 20(4):316-324. doi: 10.3321/j.issn:1001-7410.2000.04.002JIANG Zhongcheng. Carbon cycle and ecological effects in epi-karst systems in Southern China[J]. Quaternary Sciences, 2000, 20(4): 316-324. doi: 10.3321/j.issn:1001-7410.2000.04.002 [27] 李小方. 岩溶环境中土壤—植物系统钙元素形态分析及其生态意义[D]. 桂林:广西师范大学, 2006.LI Xiaofang. Speciation of calcium in soil and plants leaves in karst ecosystem and its ecological significance[D]. Guilin: Guangxi Normal University, 2006. [28] Yannikos N, Leinweber P, Helgason B L, Walley C, Van Rees F L, Ken C J. Impact of populus trees on the composition of organic matter and the soil microbial community in Orthic Gray Luvisols in Saskatchewan (Canada)[J]. Soil Biology & Biochemistry, 2014, 70(2): 5-11. [29] Jiang Zhongcheng, Lian Yanqing, Qin Xiaoqun. Rocky desertification in Southwest China: Impacts, causes, and restoration[J]. Earth-Science Reviews, 2014, 132(1): 1-12. [30] Tong Xiaowei, Martin Brandt, Yue Yuemin, et al. Forest management in Southern China generates short term extensive carbon sequestration[J]. Nature Communications, 2020, 11: 129. doi: 10.1038/s41467-019-13798-8