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林业科学 ›› 2015, Vol. 51 ›› Issue (7): 1-8.doi: 10.11707/j.1001-7488.20150701

• 论文与研究报告 • 上一篇    下一篇

湖南会同3个林龄杉木人工林土壤碳、氮、磷化学计量特征

曹娟1, 闫文德1,2,3, 项文化1,2,3, 谌小勇1,2,4, 雷丕锋1,2   

  1. 1. 中南林业科技大学 长沙 410004;
    2. 南方林业生态应用技术国家工程实验室 长沙 410004;
    3. 湖南会同杉木林生态系统国家野外科学观测研究站 会同 418307;
    4. 州长州立大学 伊利诺伊州 60484
  • 收稿日期:2014-06-17 修回日期:2015-05-13 出版日期:2015-07-25 发布日期:2015-08-14
  • 通讯作者: 谌小勇
  • 基金资助:

    国家林业公益性行业科研专项(201404316); 湖南省自然科学基金创新群体项目(湘基金委字[2013]7号); 城市森林生态湖南省重点实验室运行项目; 湖南省优势重点学科项目; 湖南省"百人计划"项目(0842); 中南林业科技大学研究生科技创新基金项目(CX2014A04); 国家林业局软科学研究项目(2013-R09); 中南林业科技大学青年科学基金项目"杉木林健康经营技术研究"。

Stoichiometry Characterization of Soil C, N, and P of Chinese Fir Plantations at Three Different Ages in Huitong, Hunan Province, China

Cao Juan1, Yan Wende1,2,3, Xiang Wenhua1,2,3, Chen Xiaoyong1,2,4, Lei Pifeng1,2   

  1. 1. Central South University of Forestry and Technology Changsha 410004;
    2. National Engineering Laboratory for Applied Technology of Forestry & Ecology in South China Changsha 410004;
    3. Huitong National Field Station for Scientific Observation and Research of Chinese Fir Plantation Ecosystem in Hunan Province Huitong 418307;
    4. Governors State University Illinois 60484
  • Received:2014-06-17 Revised:2015-05-13 Online:2015-07-25 Published:2015-08-14

摘要:

[目的] 研究不同林龄(7,17和25年生)杉木人工林土壤有机碳、全氮和全磷含量及其生态化学计量特征,探讨土壤层次分布规律及随年龄的变化规律,以期为杉木人工林可持续经营提供理论依据。[方法] 以湖南会同杉木林生态系统国家野外科学观测研究站基地内3块不同林龄的杉木人工林为研究对象,在每个林分内设置3块20 m×20 m样地,按照随机、等量和多点混合的原则,每块样地内采用"品"字形布点,按0~20, 20~40 和40~60 cm土层取样,测定土壤有机碳、全氮和全磷含量,并计算土壤碳、氮、磷之间的计量比。[结果] 7,17和25年生杉木人工林土壤有机碳含量为12.14~19.52 g·kg-1,全氮含量为1.43~1.89 g·kg-1,全磷含量为0.32~0.40 g·kg-1; 3个林分土壤有机碳含量和全氮含量随着土壤深度(0~60 cm)增加而逐渐降低, 全磷含量在土壤垂直结构上的差异不明显; 3个林龄杉木人工林的土壤C:N随林龄增加而下降,分别为11.73,8.70和8.52,对照样地炼山造林前土壤C:N为9.52,7年生幼龄林显著高于对照样地,对照样地显著高于17年生中龄林和25年生近熟林(P<0.05); 土壤C:P分别为57.42,36.27和40.54,对照样地为55.70,低于我国平均值61,7年生幼龄林、对照样地显著高于17年生中龄林和25年生近熟林(P<0.05); 土壤N:P分别为4.87,4.18,4.76,差异不显著(P>0.05),低于我国土壤平均值5.2,而炼山造林前为5.85,显著高于3个林龄杉木人工林土壤N:P(P<0.05); 3个林龄杉木人工林土壤C:N:P分别为56:5:1,36:4:1和41:5:1,炼山造林前为55:6:1,均低于我国平均值(60:5:1)。[结论] 通过对不同林龄杉木人工林土壤碳、氮、磷含量的研究发现,随着炼山后造林时间的推移,土壤有机碳、全氮、全磷含量逐渐得到恢复。本研究杉木人工林土壤中的氮含量相对较高,而磷含量较为缺乏,为了达到土壤中磷的相对平衡,在土壤C:P较低的情况下土壤微生物体有机磷会出现净矿化现象。3个林龄杉木人工林土壤C:N,N:P和C:P在不同土壤剖面深度上变化不大,相对稳定。该研究区土壤C:N和C:P主要受土壤有机碳的影响,因此在杉木人工林经营管理过程中如何调控土壤中机碳含量显得十分关键。

关键词: 杉木人工林, 土壤, 碳, 氮, 磷, 生态化学计量, 林分年龄

Abstract:

[Objective] Soil organic C,total N ,and total P were measured in Chinese fir plantations at 3 different ages (7-, 17-, and 25-year-old) and changes of these elements along soil profile were also investigated in these plantations, in order to provide a scientific basis for sustainable management of Chinese fir plantations. [Method] The study was conducted at the National Key Field Observation Station of Central South University of Forestry and Technology, located in Huitong, Hunan Province of China. Three plantations at different ages were selected within the station and three plots in size of 20 m×20 m were set up for each of the three plantations. Based on the principle of ‘random’, ‘equal’ and ‘pooled’, soil samples were collected from 0-20, 20-40, and 40-60 cm depths, respectively, at three sampling points with a triangle shape within each plot. Soil organic C, total N and total P were analyzed. C:N, C:P, N:P and C:N:P ratios were estimated. [Result] The contents of soil organic C,total N, and total P ranged 12.14-19.52, 1.43-1.89,and 0.32-0.40 g·kg-1 in the studied plantations, respectively. The contents of soil organic C and total N decreased with the increase of soil depths in 7-, 17-and 25-year-old stands. Total P contents did not significantly differ among soil depths in the studied stands. Soil C:N of the 3 plantations was respectively 11.73, 8.70, and 8.52, displaying a declining trend with aging.. In addition, soil C:N ratio was significantly higher in 7-year-old plantations (P<0.05) and significantly lower in 17- and 25-year-old plantations (P<0.05) when compared to the control plots (9.52) (plots with slash burning but before afforestation). Soil C:P ratios were 57.42, 36.27, and 40.54 in the studied plantations and 55.70 in the control, which were all lower than the national mean (61). Soil C:P ratios were significantly higher in 7-year-old plantations and the control plots than in 17- and 25-year old plantations. Soil N:P ratios were 4.87, 4.18 and 4.76 in the studied plantations and no significant differences from each other. But soil N:P ratios were lower in the studied plantations compared to the national mean (5.2), and significantly lower when compared to the control (5.85) (P<0.05). Soil C:N:P ratios were 56:5:1,36:4:1,41:5:1 in the three plantations and 55:6:1 in the control, all were lower than the national mean (60:5:1). [Conclusion] Soil C, N ,and P contents were gradually restored with the aging of plantations. Our study suggested that N was relatively adequate, but P was relatively lack in the studied sites. It was likely that net mineralization of soil microbial biomass P occurred in order to maintain a relative equilibrium of P in soils under low soil C:P ratio condition. Soil C:N, N:P ,and C:P ratios were in a relative steady state along soil profile in the plantations. Soil C:N and C:P ratios were mainly affected by soil total C in the study area. As a consequence, to regulate soil organic C content is a critical target in sustainable management of Chinese fir plantations.

Key words: Chinese fir plantation, soil, carbon, nitrogen, phosphorus, stoichiometry, plantation age

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