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应用生态学报 ›› 2019, Vol. 30 ›› Issue (7): 2267-2274.doi: 10.13287/j.1001-9332.201907.001

• 研究报告 • 上一篇    下一篇

放牧高寒嵩草草地不同演替阶段土壤酶活性及养分演变特征

李茜, 孙亚男, 林丽, 李以康, 杜岩功, 郭小伟, 杨永胜, 曹广民*   

  1. 中国科学院西北高原生物研究所, 青海省寒区恢复生态学重点实验室/高原生物适应与进化重点实验室, 西宁 810008
  • 收稿日期:2018-11-26 出版日期:2019-07-15 发布日期:2019-07-15
  • 通讯作者: * E-mail: caogm@nwipb.cas.cn
  • 作者简介:李茜,女,1986年生,博士,助理研究员.主要从事高寒草地土壤养分循环及微生物研究.E-mail:liqian@nwipb.cas.cn
  • 基金资助:
    青海省自然科学基金项目(2016-ZJ-923Q)、国家自然科学基金项目(31400483)、国家重点基础研究发展计划项目(2014CB954002)、青海省创新平台建设专项(2017-ZJ-Y20)和中国科学院西部之光B类项目: 三江源退化高寒草甸恢复过程中的水分效应研究

Changes of soil enzyme activities and nutrients across different succession stages of grazing alpine Kobresia grassland.

LI Qian, SUN Ya-nan, LIN Li, LI Yi-kang, DU Yan-gong, GUO Xiao-wei, YANG Yong-sheng, CAO Guang-min*   

  1. Qinghai Province Key Laboratory of Restoration Ecology for Cold Regions/Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China.
  • Received:2018-11-26 Online:2019-07-15 Published:2019-07-15
  • Contact: * E-mail: caogm@nwipb.cas.cn

摘要: 以高寒草地演替序列禾草-矮嵩草群落、矮嵩草群落、加厚期小嵩草群落、开裂期小嵩草群落和杂类草-黑土型次生裸地为对象,研究多稳态放牧高寒草地土壤酶活性演变及其与养分的关联性.结果表明: 随退化演替推进,植被盖度和地上生物量依次降低,而地下生物量在加厚期和开裂期小嵩草群落达到高峰.土壤蔗糖酶、脲酶、纤维素酶、碱性磷酸酶和芳基硫酸酯酶活性在土壤表层(0~10 cm)高于亚表层(10~20 cm),而几丁质酶相反;纤维素酶、碱性磷酸酶和芳基硫酸酯酶在禾草-矮嵩草群落最高,杂类草-黑土型次生裸地最低,加厚期小嵩草群落略有升高;几丁质酶在中间3个阶段均显示较高活性;脲酶和蔗糖酶在后期杂类草-黑土型次生裸地阶段明显升高.土壤水分、铵态氮、碱解氮、全氮、全碳和有机碳随退化演替依次递减,但硝态氮和速效磷在后期两阶段回升.除几丁质酶外,其他酶均与速效磷、铵态氮、碱解氮、全碳和有机碳呈正相关,与pH呈负相关;纤维素酶、碱性磷酸酶和芳基硫酸酯酶还与土壤水分和全氮呈正相关;影响土壤酶活性的主控因子为速效磷和铵态氮.高寒草地土壤酶受放牧退化演替影响呈现不同演变趋势,酶活性与土壤养分存在相互协同作用,但重度退化的极端环境也可能会激发与氮、碳养分转化相关的土壤酶活性.

Abstract: The variation of soil enzyme activity and relevance with soil nutrients was examined in multistable grazing alpine Kobresia grassland, including Gramineae-Kobresia humilis community, K. humilis community, K. pygmaea community at thickened stage, K. pygmaea community at cracked stage and forb-black soil type secondary bare land. The results showed that the vegetation coverage and aboveground biomass successively decreased with degenerative succession. The belowground biomass was the highest in the K. pygmaea community at thickened and cracked stages. The activities of soil sucrase, urease, cellulase, alkaline phosphatase and aryl sulfatase were higher at the surface soil layer (0-10 cm) than those at the subsurface soil layer (10-20 cm), while the pattern of chitinase activity was contrary. The activities of cellulase, alkaline phosphatase and aryl sulfatase were the highest in the Gramineae-K. humilis community and the lowest at the forb-black soil type secondary bare land, and they slightly increased during the thickened stage of K. pygmaea community. Chitinase activity was relatively high at the middle three stages, while urease and sucrase activity had an obvious increase in the forb-black soil type secondary bare land. Soil moisture, ammonium, alkali-hydrolyzable nitrogen, total nitrogen, total carbon and organic carbon successively decreased with degenerative succession, whereas the concentrations of nitrate and available phosphorus increased at the latter two succession stages. The activities of the other enzymes, except for chitinase, were significantly positively correlated with the soil available phosphorus, ammonium, alkali-hydrolyzed nitrogen, total carbon, and organic carbon, and negatively correlated with soil pH. The activities of cellulose, alkaline phosphatase and aryl sulfatase were significantly positively correlated with soil moisture and total nitrogen. The main factors affecting soil enzyme activity were available phosphorus and ammonium. Soil enzymes showed different evolutionary trends influenced by grazing degradation succession in the alpine grassland, with a synergistic effect with soil nut-rients. Moreover, severely degraded extreme environments may stimulate soil enzyme activities related to nitrogen and carbon transformation.