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林业科学 ›› 2018, Vol. 54 ›› Issue (2): 162-169.doi: 10.11707/j.1001-7488.20180219

• 研究简报 • 上一篇    下一篇

高寒沙地中间锦鸡儿和柠条锦鸡儿细根分解动态特征

何凌仙子1, 贾志清1,2, 刘涛3, 李清雪1,2, 张友焱1,2, 石坤4, 冯莉莉1, 杨凯悦1, 赵雪彬2   

  1. 1. 中国林业科学研究院荒漠化研究所 北京 100091;
    2. 青海共和荒漠生态系统定位观测研究站 共和 813005;
    3. 中国林业科学研究院林业研究所 北京 100091;
    4. 北京林业大学水土保持学院 北京 100083
  • 收稿日期:2017-06-21 修回日期:2018-01-09 出版日期:2018-02-25 发布日期:2018-03-30
  • 基金资助:
    林业公益性行业科研专项(201504420);国家自然科学基金项目(31670706,31600585)。

Dynamic Characteristics of Fine Root Decomposition of Two Caragana Species with in Alpine Sandy Land

He Lingxianzi1, Jia Zhiqing1,2, Liu Tao3, Li Qingxue1,2, Zhang Youyan1,2, Shi Kun4, Feng Lili1, Yang Kaiyue1, Zhao Xuebin2   

  1. 1. Institute of Desertification Studies, CAF Beijing 100091;
    2. Qinghai Gonghe Desert Ecosystem Research Station Gonghe 813005;
    3. Research Institute of Forestry, CAF Beijing 100091;
    4. College of Soil and Water Conservation, Beijing Forestry University Beijing 100083
  • Received:2017-06-21 Revised:2018-01-09 Online:2018-02-25 Published:2018-03-30

摘要: [目的]分析青海共和盆地1990年种植的中间锦鸡儿和柠条锦鸡儿人工灌丛的细根分解状况,探讨不同径级细根分解规律、元素释放规律及其影响因素,评价2种锦鸡儿人工灌丛在共和盆地的长期适应性,为长期研究高寒沙地土壤碳循环和养分循环规律提供理论依据。[方法]利用埋袋法,比较不同径级(0~0.5、0.5~1和1~2 mm)细根经历489天分解期后的质量损失率和元素(C、N、P和K)释放率,研究分解速率与初始元素含量的相关性,总结2种锦鸡儿细根分解动态特征;运用非线性指数衰减模型拟合估算细根分解系数及分解50%和95%所需时间。[结果]2种锦鸡儿细根在前60天均快速分解,各径级细根质量残留率为53.28%~66.34%,122~367天进入缓慢分解阶段,367~420天分解速率缓慢上升,420天后细根质量显著下降,残留率为39.94%~58.20%;树种、径级和分解时间对细根质量损失率影响显著;中间锦鸡儿0~0.5、0.5~1和1~2 mm细根质量损失95%所需时间分别为17.18、14.96和12.57年,柠条锦鸡儿所需时间分别为27.35、26.41和14.77年;分解489天后,中间锦鸡儿和柠条锦鸡儿细根C分别释放了56.34%~79.70%和44.37%~87.39%,N分别释放了62.73%~83.43%和54.41%~88.63%,树种、径级和分解时间的两两交互对元素释放率影响不显著。[结论]中间锦鸡儿各径级细根的分解速率和元素累积释放率均大于柠条锦鸡儿,即中间锦鸡儿的细根,尤其是1~2 mm细根向土壤中释放化学元素(C、N、P和K)的速率更快,更有利于土壤有机碳循环和养分循环,对高寒沙地土壤改良效益更显著。在高寒沙地应当选择中间锦鸡儿作为防风固沙、改良土壤的典型树种。

关键词: 高寒沙地, 锦鸡儿, 细根分解, 径级, 元素释放

Abstract: [Objective] Fine root decomposition law, element release rule and corresponding influencing factors were analyzed towards Caragana intermedia and Caragana korshinskii plantations in Qinghai alpine sandy land in 1990, which contributed to the evaluation of long-term adaptability of these two Caragana plantations in Gonghe Basin, and further provided theoretical basis on long-term research of Alpine sandy soil's carbon and nutrient cycle.[Method] The buried bag method was adopted in May 2015, and comparison was done on mass loss rate and element (C, N, P, K) release rate between the two Caragana species with fine roots of different diameters (1-2, 0.5-1,and 0-0.5 mm) during 489 days' decomposition process. The correlation between initial concentrations and mass loss rates was studied, and dynamic characteristics of fine root decomposition was analyzed. In addition, fine root decomposition coefficient and the time required for 50% and 95% decomposition were determined by nonlinear exponential regression.[Results] Mass residual rate was 53.28%-66.34% after 120 days' rapid decomposition process, followed by a slow decomposition phase (120-360 d) and slowly speeding period (360-489 d). Fine root mass of the two Caragana species experienced a remarkable drop after 489 days' decomposition, and mass residual rate achieved 39.94%-58.20%. Tree species, fine root diameter class and decomposition time had significant effect on fine root mass loss rate, respectively. Time for 95% decomposition was 17.18,14.96,and 12.57 a for Caragana intermedia with fine root diameter of 0-0.5, 0.5-1, and 1-2 mm, respectively, while 27.35, 26.41, and 14.77 a for Caragana korshinskii. Chemical elements release rate of C was 56.34%-79.70% and 44.37%-87.39% for Caragana intermedia and Caragana korshinskii, respectively, while the value of N achieved 62.73%-3.43% and 54.41%-8.63% after 489 days' decomposition. Pairwise interaction of tree species, fine root diameter class and decomposition time had non significant effect on element release rate.[Conclusion] In this study, fine root decomposition rate and cumulative element release rate of Caragana intermedia was larger than that of Caragana korshinskii. Fine root of Caragana intermedia, especially those with Ø1-2 m, released chemical elements (C, N, P, K) faster, which contributed to circulation of soil organic carbon and nutrients, and further benefited soil amelioration in alpine sandy area. Therefore, Caragana intermedia should be selected as typical tree species for wind break, sand fixation and soil reclamation.

Key words: alpine sandy land, Caragana, fine root decomposition, diameter, element release

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