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草业学报 ›› 2021, Vol. 30 ›› Issue (4): 46-57.DOI: 10.11686/cyxb2020195

• 研究论文 • 上一篇    下一篇

宁夏东部荒漠草原向灌丛地转变过程土壤微生物响应

顾继雄1(), 郭天斗2, 王红梅1,2(), 李雪颖2, 梁丹妮2, 杨青莲2, 高锦月2   

  1. 1.宁夏大学农学院,宁夏 银川 750021
    2.西北退化生态系统恢复与重建教育部重点实验室,宁夏 银川 750021
  • 收稿日期:2020-04-28 修回日期:2020-08-04 出版日期:2021-04-20 发布日期:2021-03-16
  • 通讯作者: 王红梅
  • 作者简介:Corresponding author. E-mail: whm_826@163.com
    顾继雄(1995-),男,宁夏固原人,在读本科。E-mail: 1132526599@qq.com
  • 基金资助:
    国家自然科学基金项目(31860677);宁夏科技支撑计划项目(2015惠民计划)和宁夏高等学校一流学科建设项目(NXYLXK2017A01)

Responses of soil microbes across an anthropogenic transition from desert steppe grassland to shrubland in eastern Ningxia

Ji-xiong GU1(), Tian-dou GUO2, Hong-mei WANG1,2(), Xue-ying LI2, Dan-ni LIANG2, Qing-lian YANG2, Jin-yue GAO2   

  1. 1.School of Agriculture,Ningxia University,Yinchuan 750021,China
    2.Key Laboratory of Restoration and Reconstruction of Degraded Ecosystems in Northwest China,Ministry of Education,Yinchuan 750021,China
  • Received:2020-04-28 Revised:2020-08-04 Online:2021-04-20 Published:2021-03-16
  • Contact: Hong-mei WANG

摘要:

为探究荒漠草原向灌丛地人为转变过程中土壤微生物及其酶活性的响应特征,选取宁夏东部荒漠草原近30年典型草地-灌丛地镶嵌体区域的荒漠草地、草地边缘、灌丛边缘、灌丛地为研究样地,开展各样地不同微生境(植丛和空斑)下的0~20 cm土层土壤理化性质、微生物数量、微生物生物量及其酶活性特征研究。结果显示:随转变过程各样地土壤水分、土壤有机碳、全碳、全氮以及全磷含量分别由6.84%、8.54 g·kg-1、22.67 g·kg-1、0.85 g·kg-1、0.32 g·kg-1显著下降至1.78%、5.85 g·kg-1、6.63 g·kg-1、0.16 g·kg-1、0.23 g·kg-1P<0.05),pH无明显变化。细菌数量呈先降后升变化,荒漠草地略高于灌丛地,真菌数量呈“下降-上升-再下降”非线性变化,灌丛地略高于荒漠草地,放线菌数量下降趋势明显。微生物生物量碳、氮含量分别由87.66、5.94 mg·kg-1显著下降至9.94、1.85 mg·kg-1P<0.05)。过氧化氢酶、碱性磷酸酶、蔗糖酶和脲酶活性呈显著波动或线性下降趋势,荒漠草地均显著大于灌丛地(P<0.05)。土壤微生物特性和酶活性在各样地不同微生境均表现为植丛显著大于空斑(P<0.05)。随着植被转变过程土壤水分、全碳、全氮与土壤微生物(放线菌、土壤微生物量碳氮、过氧化氢酶、脲酶、碱性磷酸酶)呈极显著正相关(P<0.01),土壤有机碳、全磷与土壤微生物量碳、脲酶呈显著正相关(P<0.05),pH与土壤微生物无显著关系(P>0.05);放线菌数量、过氧化氢酶、碱性磷酸酶和脲酶活性与微生物量碳、氮呈极显著正相关(P<0.01),细菌、真菌数量和蔗糖酶活性与微生物量碳、氮呈正相关(P>0.05)。荒漠草原向灌丛地过渡转变过程,虽各指标存在升高、降低或过渡边界效应,但当过渡到灌丛地均显著低于荒漠草地,表明该年限灌丛地土壤微生物活性显著降低。

关键词: 荒漠草原, 灌丛地, 人为转变, 土壤微生物数量, 土壤微生物生物量, 土壤微生物酶

Abstract:

This research investigated the impacts on soil microbes and their enzyme activities, of the anthropogenic transition process from desert steppe to shrubland vegetation. Four site categories: desert grassland (DG), grassland edge (GE), shrubland edge (SE) and shrubland (SL) in grassland-shrubland mosaic were selected to represent the transition process, and soil properties, microbial population counts, microbial biomass and enzyme activity in the 0-20 cm soil layer under vegetation patches (VP) and bare interspaces (BI) at each site were measured. It was found that soil moisture, soil organic carbon, total carbon, total nitrogen and total phosphorus decreased from 6.84%, 8.54 g·kg-1, 22.67 g·kg-1, 0.85 g·kg-1, 0.32 g·kg-1 in DG to 1.78%, 5.85 g·kg-1, 6.63 g·kg-1, 0.16 g·kg-1, 0.23 g·kg-1 in SL, respectively (P<0.05), while pH was not significantly changed. Across the transition, bacteria numbers were lowest at GE and SE sites, and slightly lower in SL than DG. Fungi showed a “decrease-rise-decrease” trend, with slightly higher population numbers in SL than in DG. Actinomycete population numbers decreased significantly in SL, compared to DG. The amount of microbial biomass carbon and nitrogen decreased from 87.66 and 5.94 mg·kg-1 in DG, to 9.94 and 1.85 mg·kg-1 in SL, respectively (P<0.05). The activities of catalase, alkaline phosphatase and sucrase showed a significant “decrease-rise-decrease” decline trend in the transition from DG to SL, and urease activity was significantly lower in DG than in SL (P<0.05). The soil microbe characteristics and enzyme activities were significantly higher under VP than in BI (P<0.05). Across the vegetation transition, soil moisture, total carbon and total nitrogen were positively correlated with soil microbe-related parameters (actinomycete numbers, soil microbial biomass carbon and nitrogen, and catalase, urease, alkaline phosphatase activities) (P<0.01), and soil organic carbon and total phosphorus were significantly correlated with soil microbial biomass carbon and urease activity (P<0.05), while pH was not significantly correlated with soil microbe-related parameters (P>0.05). Actinomycete numbers, and the enzymatic activities of catalase, alkaline phosphatase and urease were positively correlated with microbial biomass carbon and nitrogen (P<0.01). However, the numbers of bacteria and fungi and sucrase activities were not significantly correlated with microbial biomass carbon and nitrogen. Across the DG-SL ecological boundary transition (established nearly 30 years), the indexes observed differed between DG and SL, with SL being significantly lower than DG in most cases, showing that the soil microbial activity of DG is significantly decreased after 30 years as shrubland.

Key words: desert steppe, shrubland, anthropogenic transition, soil microbial quantity, soil microbial biomass, soil microbial enzyme