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针阔凋落叶混合分解过程中可溶性有机碳释放的动态特征 |
李 勋1, 张 艳1, 宋思梦1, 周 扬1, 张 健2*
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1. 四川民族学院, 横断山区生态修复与特色产业培育研究中心, 四川 康定 626001;2. 四川农业大学 林学院
生态林业研究所, 生态林业工程重点实验室, 长江上游生态安全协同创新中心, 成都 611130
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摘要: |
为了调整低效马尾松(Pinus massoniana, P)人工纯林的林分结构,探明其与乡土阔叶树种凋落叶混合分解过程中的可溶性有机碳(DOC)释放规律,该研究以马尾松、香樟(Cinnamomum camphora, C)和香椿(Toona sinensis, T)的凋落叶为研究对象,将其按照不同树种和质量比例组合为15个处理(3个单一树种处理 + 12个混合处理)后进行野外凋落叶分解实验,并探讨DOC释放最佳的凋落叶树种组合以及混合比例。结果表明:(1)马尾松和大部分混合处理凋落叶(除了PT64)在分解初期(0~6个月)的DOC含量均显著升高,出现富集现象,之后随着分解时间的延长而降低,在分解中后期(12~18个月)或分解末期(18~24个月)再次出现小幅度的碳富集现象。阔叶所占比例越高,其后期DOC含量越低。(2)分解前期(0~6个月)凋落叶DOC释放的拮抗效应较强(58.33%),仅有8.33%(1/12)的混合处理表现出协同效应。之后(6~18个月)其协同效应逐渐增强(91.67%),分解末期(18~24个月)凋落叶的协同效应有所减弱(66.67%)。在所有混合处理中,PT64在整个分解期间均出现协同效应,其次为PT73、PCT622和PCT613在大部分分解时期(3/4)出现协同效应。(3)偏最小二乘法(PLS)回归分析表明,凋落叶初始质量因子中N含量、P含量、木质素含量、缩合单宁含量、C/N、C/P、木质素/N以及木质素/P是影响该研究区域中凋落物DOC释放的重要因素。总体而言,马尾松与阔叶凋落叶混合后的DOC释放受到树种、混合比例及分解时间的共同影响。相对于其他混合处理,阔叶占比大于等于30.00%且含有香椿(T)的凋落叶混合处理(PT64、PT73、PCT622和PCT613)更能促进DOC的释放。 |
关键词: 马尾松, 乡土阔叶树种, 混合凋落叶, 可溶性有机碳, 协同效应, 拮抗效应 |
DOI:10.11931/guihaia.gxzw202305020 |
分类号:Q945.1 |
文章编号:1000-3142(2024)07-1205-13 |
Fund project:四川省科技计划项目(2023NSFSC1168); 四川省科技支撑计划项目(12ZC0017); 甘孜州科技计划项目(220030)。 |
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Dynamic characteristics of dissolved organic carbon release from the mixed leaf litter decomposition of coniferous and broad-leaved tree species |
LI Xun1, ZHANG Yan1, SONG Simeng1, ZHOU Yang1, ZHANG Jian2*
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1. Research Center for Ecological Restoration and Characteristic Industry Cultivation in Hengduan Mountains Region, Sichuan Minzu College,
Kangding 626001, Sichuan, China;2. Key Laboratory of Forestry Ecological Engineering in Sichuan, Collaborative Innovation Center
of Ecological Security in the Upper Reaches of Yangtze River, Institute of Foresty Ecological, College
of Forestry, Sichuan Agricultural University, Chengdu 611130, China
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Abstract: |
In order to adjust the structure of inefficient Pinus massoniana(P)forest and explore the dynamic changes for dissolved organic carbon(DOC)during the mixed decomposition process of P. massoniana and native broad-leaved tree species. Our research focuses on the leaf litter of P. massoniana, Cinnamomum camphora(C)and Toona sinensis(T), and combine them into the 15 treatments(3 single tree treatments + 12 mixed treatments)according to different tree species combinations and mass proportions, and then conducted field decomposition experiments to further explore the optimal tree species combination and the proportion of mixed planting for DOC release. The results were as follows:(1)DOC content of Pinus massoniana and most of mixed treatments(except for PT64)significantly increased during the early stages of decomposition(0-6 months), leading to carbon enrichment. The DOC content of leaf litter decreased with the extension of decomposition time, and also exhibited carbon enrichment in small degree during the middle to late stages of decomposition(12-18 months)or the late stages of decomposition(18-24 months). Mixed leaf litter showed that the higher the proportion of broad-leaved, the lower the DOC content in the later stage.(2)The antagonistic effect of DOC release rate in the early stage of decomposition(0-6 months)was strong(58.33%), and only 8.33%(1/12)of mixed treatments showed the synergistic effect. Its synergistic effect gradually strengthened(91.67%)after 6-18 months, but the synergistic effect of leaf litter(66.67%)during the late stage of decomposition weakened(18-24 months). Among all mixed treatments, PT64 exhibited synergistic effects throughout the entire decomposition stage, followed by PT73, PCT622 and PCT613(3/4).(3)Partial least-squares(PLS)regression showed that N content, P content, lignin content, condensed tannin content, C/N, C/P, lignin/N, and lignin/P were important quality factors affecting the release of DOC from litter in this study area. Overall, the DOC release from mixed Pinus massoniana and broad-leaved leaf litter is affected by tree species, mixed proportion and decomposition time. Compared to other mixed treatments, the proportion of broad-leaved greater is than or equal to 30.00% and the mixed leaf litter treatments including Toona sinensis(PT64, PT73, PCT622 and PCT613)show strong synergistic effects for DOC release. |
Key words: Pinus massoniana, native broad-leaved tree species, mixed leaf litter, dissolved organic carbon, synergistic effects, antagonistic effects |
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