欢迎访问林业科学,今天是

林业科学 ›› 2022, Vol. 58 ›› Issue (6): 13-22.doi: 10.11707/j.1001-7488.20220602

•   • 上一篇    下一篇

青海高寒区4种人工林细根生物量及其养分储量变化特征

张雪,王冬梅*,温文杰,刘若莎   

  1. 北京林业大学水土保持学院 北京 100083
  • 收稿日期:2021-01-03 出版日期:2022-06-25 发布日期:2022-09-24
  • 通讯作者: 王冬梅
  • 基金资助:
    国家重点研发计划"高寒丘陵区林草植被的结构优化与功能提升技术和示范"(2017YFC0504604)

Seasonal Patterns in Fine Root Biomass and Nutrient Storage of Four Plantations in the Alpine Region of Qinghai Province

Xue Zhang,Dongmei Wang*,Wenjie Wen,Ruosha Liu   

  1. School of Soil and Water Conservation, Beijing Forestry University Beijing 100083
  • Received:2021-01-03 Online:2022-06-25 Published:2022-09-24
  • Contact: Dongmei Wang

摘要:

目的: 研究青海高寒区4种人工林的细根生物量及其养分储量时空变化特征, 为该地区植被恢复和人工林经营提供理论依据。方法: 在青海高寒区选择白桦、青杨、华北落叶松和青海云杉4种典型人工纯林, 2019年5—10月采集0~60 cm土层细根样品, 测定细根生物量及其C、N、P含量, 通过方差分析探究季节、树种和土层对细根生物量及其养分储量的影响。结果: 白桦、青杨、华北落叶松和青海云杉4种人工林0~60 cm土层的细根生物量分别为7.63、6.89、6.11和19.31 t·hm-2, 青海云杉林细根生物量显著高于其他林分(P<0.05)。各林分细根生物量季节差异显著(P<0.05), 均表现为秋季>夏季>春季。细根生物量主要分布在表层土壤, 0~20 cm土层占比超过68%, 随土层加深呈指数型降低。阔叶林细根的养分含量高于针叶林, 阔叶林生长表现出较高的养分需求。各林分细根C含量表现为秋季>夏季>春季, N、P含量总体表现为夏季显著低于春季和秋季(P<0.05)。细根C、N和P含量总体上随土层加深而减小。青海云杉林细根C、N、P储量在各季节均显著高于其他树种; 秋季细根C、N和P储量显著高于春季和夏季(P<0.05)。结论: 青海高寒区4种人工林细根生物量和C、N、P含量及储量存在明显的季节变化和垂直分布特征, 秋季细根生物量最高, 细根主要分布在表层土壤并随土层加深呈指数型减少趋势; 细根的C、N、P储量时空变化规律与细根生物量一致, 在4种人工林中以青海云杉林最高。青海高寒区人工林经营应结合季节特征, 在生长季初期通过合理经营措施促进细根生长发育, 并注重保护表层细根资源以提高植被恢复力。

关键词: 人工林, 细根, 细根生物量, 细根养分储量, 青海高寒区

Abstract:

Objective: Due to the special geographical location, the ecological environment of alpine region in Qinghai Province is fragile and the growth of vegetation is poor. The objective of this research was to investigate seasonal variation and vertical distribution of fine root biomass and nutrient storage of typical plantations in this region. The result would provide a theoretical basis for vegetation restoration and plantation management in alpine region in Qinghai Province. Method: Four typical plantations namely Betula platyphylla, Populus cathayana, Larix principis-rupperchii, and Picea crassifolia were selected in the Taergou watershed of Datong County, Qinghai Province. Samples of fines roots in 0-60 cm soil layer were collected from May to October in 2019 from each plantation type. The fine root biomass and their C (carbon), N (nitrogen), and P (phosphorus) contents were analyzed. We used variance analysis to explore the effect of seasons, plantation types and soil layers on fine root biomass and nutrient storage. Result: During the growing season, the fine root biomass of B. platyphylla, P. cathayana, L. principis-rupperchii, and P. crassifolia in the 0-60 cm soil layer was 7.63, 6.89, 6.11, and 19.31 t·hm-2, respectively. The fine root biomass of P. crassifolia was significantly higher than that of the other plantations. The fine root biomass of the four plantations were all decreased in the order of autumn > summer > spring, with significant difference between seasons (P < 0.05). With the increase of depth of the soil layer, the fine root biomass of the four plantations decreased exponentially. Fine root biomass mainly concentrated in the surface soil layer (0-20 cm), accounting for more than 68% of the total for all the four plantations. The fine root nutrient content of broad-leaved forest was relatively higher than that in coniferous forest, indicating that broad-leaved forest needs more nutrients for its growth. The fine root C content of the four plantations were all decreased in the order of autumn > summer > spring, while the fine root N and P contents in autumn were significantly higher during the growing season (P < 0.05). In vertical variation, the fine root nutrient content generally showed a trend of decreasing with the increase of soil depth. The fine root nutrient storage of P. crassifolia was significantly higher than that of the other species during the growing season. The fine root nutrient storage was the highest in autumn. Conclusion: The fine root biomass, fine root nutrient content and storage of the four plantations in the alpine region of Qinghai Province had significant seasonal variation and vertical distribution pattern. The fine root biomass in autumn was the highest. The fine roots were mainly concentrated in the surface soil layer and decreased with the depth of soil layer, showing an obvious property of surface-aggregation. The seasonal variation and vertical distribution of fine root C, N, and P storage were consistent with the fine root biomass. Among the four plantations, the fine root C, N, and P storage of P. crassifolia were relatively high. Therefore, we suggested that the plantation management in this area should be combined with seasonal characteristics. It is important to promote the growth and development of fine roots by reasonable management measures in the early growing seasons, and to protect the accumulation of surface fine roots in order to ensure vegetation resilience can be improved.

Key words: plantations, fine root, fine root biomass, nutrient storage of fine root, the alpine region of Qinghai Province

中图分类号: