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草业学报 ›› 2017, Vol. 26 ›› Issue (8): 200-206.DOI: 10.11686/cyxb2016378

• 研究简报 • 上一篇    下一篇

沙地植物根系特征及其与土壤有机碳和总氮的关系

罗永清, 赵学勇, 王涛, 李玉强   

  1. 中国科学院西北生态环境资源研究院,甘肃 兰州 730000
  • 收稿日期:2016-10-09 出版日期:2017-08-20 发布日期:2017-08-20
  • 作者简介:罗永清(1984-),男,陕西宝鸡人,助理研究员,博士。E-mail:luoyongqing8401@sina.com
  • 基金资助:
    国家自然基金项目(31500369),中国科学院“百人计划”项目(Y551821001),国家科技基础资源调查专项(2017FY100200)和国家重点研发计划课题(2016YFC0500907)资助

Characteristics of the plant-root system and its relationships with soil organic carbon and total nitrogen in a degraded sandy grassland

LUO Yong-Qing, ZHAO Xue-Yong, WANG Tao, LI Yu-Qiang   

  1. Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
  • Received:2016-10-09 Online:2017-08-20 Published:2017-08-20

摘要: 以位于风沙活动剧烈的科尔沁沙地为研究区,通过对不同恢复阶段的流动沙丘、半固定沙丘、固定沙丘和封育草地4种生境的植物特征和土壤总有机碳(SOC)和总氮(TN)含量进行调查,分析了沙地不同恢复阶段土壤碳氮特征与植物的关系。结果表明,1)植物地上和地下生物量的变化随沙地恢复过程呈现不同的特征,地上生物量随沙地恢复表现为先增加后减小的趋势,地下生物量则为指数增加的特征,封育草地植物的根冠比显著高于其他恢复阶段;2)与生物量类似,根系长度和根表面积均随沙地恢复逐渐增加,生境间差异极显著,而根体积虽存在生境间差异,但随沙地恢复梯度的规律性不明显;3)SOC和TN的含量与储量均随沙地恢复逐渐增加,0~10 cm层SOC和TN含量高于10~20 cm层,但随沙地恢复过程,10~20 cm层的增幅高于0~10 cm层;4)地上生物量和地下生物量均与SOC和TN储量呈显著的线性回归关系,地下生物量与SOC和TN储量的回归系数均高于地上生物量;5)根系长度和根表面积与土壤碳氮的回归系数均高于生物量和体积。本研究表明,在风沙活动剧烈的沙地生境,植物根系与土壤碳氮的关系较地上部分更为紧密,根系活动可能是影响土壤碳氮积累的重要因素之一。

Abstract: Plants are the key component of ecosystems in terms of matter exchange and energy flux. The aboveground and belowground biomasses affect carbon and nitrogen feedback processes differently in the plant-soil system. In this study, the plant characteristics, soil organic carbon (SOC), soil total nitrogen (TN), and their relationships were investigated in four different habitats in the Horqin Sandy Land; mobile dune, semi-fixed dune, fixed dune, and fenced grassland. These four habitats represent four consecutive stages of the restoration process. The results showed that plant aboveground biomass and belowground biomass varied among the habitats. Aboveground biomass initially increased and then decreased during the restoration process, while the belowground biomass showed an exponential increase during restoration. The root to shoot ratio was significantly higher in fenced grassland than in the other three habitats. Similarly to biomass, the length and surface area of plant roots significantly increased during restoration, but there was no obvious trend in the change in root volume, although it differed significantly among the four habitats. Both the contents and storage of SOC and TN increased during the restoration process. The contents of both SOC and TN were higher in the 0-10 cm soil layer than in the 10-20 cm soil layer, however, their rates of increase were higher in the 10-20 cm soil layer than in the 0-10 cm soil layer. Both the aboveground biomass and belowground biomass showed significant linear relationships with SOC and TN storage, while the regression coefficient was higher for belowground biomass than for aboveground biomass. From the perspective of plant root morphology, root length and root surface area were more strongly related than root biomass to SOC and TN. In conclusion, plant roots were more strongly related to SOC and TN than was aboveground biomass. Therefore, root activities may be an important factor for carbon and nitrogen accumulation in soil, especially in barren soils in environments with strong winds and sand-moving processes.