植物生态学报 ›› 2021, Vol. 45 ›› Issue (3): 309-320.DOI: 10.17521/cjpe.2020.0264

• 研究论文 • 上一篇    

降水量变化与氮添加下荒漠草原土壤酶活性及其影响因素

朱湾湾1,2, 王攀2, 许艺馨2, 李春环2, 余海龙2, 黄菊莹1,*()   

  1. 1宁夏大学生态环境学院, 西北土地退化与生态恢复国家重点实验室培育基地, 西北退化生态系统恢复与重建教育部重点实验室, 银川 750021
    2宁夏大学地理科学与规划学院, 银川 750021
  • 收稿日期:2020-08-03 接受日期:2020-12-22 出版日期:2021-03-20 发布日期:2021-05-17
  • 通讯作者: 黄菊莹
  • 作者简介:* 黄菊莹: ORCID:0000-0002-1351-7282 (juyinghuang@163.com)
  • 基金资助:
    宁夏高等学校一流学科建设(生态学)项目(NXYLXK2017B06);国家自然科学基金(31760144);国家自然科学基金(41961001)

Soil enzyme activities and their influencing factors in a desert steppe of northwestern China under changing precipitation regimes and nitrogen addition

ZHU Wan-Wan1,2, WANG Pan2, XU Yi-Xin2, LI Chun-Huan2, YU Hai-Long2, HUANG Ju-Ying1,*()   

  1. 1School of Ecology and Environmental Sciences, Ningxia University, Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwestern China, Key Laboratory for Restoration and Reconstruction of Degraded Ecosystems in Northwestern China of Ministry of Education, Yinchuan 750021, China
    2School of Geography Science and Planning, Ningxia University, Yinchuan 750021, China
  • Received:2020-08-03 Accepted:2020-12-22 Online:2021-03-20 Published:2021-05-17
  • Contact: HUANG Ju-Ying
  • Supported by:
    Project of First-Class Discipline Construction (Ecology) for Ningxia Higher Education(NXYLXK2017B06);National Natural Science Foundation of China(31760144);National Natural Science Foundation of China(41961001)

摘要:

土壤酶主要由植物根系和微生物分泌产生, 参与有机质降解和元素循环等重要过程。研究降水量变化和氮(N)添加下土壤酶活性及其与植物群落组成以及微生物活动间的联系, 可为深入理解全球变化背景下植被-土壤系统中元素的循环与转化机制提供科学依据。该研究基于2017年在宁夏荒漠草原设立的降水量变化(减少50%、减少30%、对照、增加30%以及增加50%)和N添加(0和5 g·m-2·a-1)的野外试验, 研究了2018-2019年土壤蔗糖酶、脲酶和磷酸酶活性的变化, 分析了其与植物群落组成、微生物生态化学计量特征的关系。结果表明: 与减少降水量相比, 增加降水量对3种酶活性的影响较大, 但其效应与N添加以及年份存在交互作用。2018年增加降水量对3种酶活性的影响缺乏明显的规律性。2019年增加降水量不同程度地提高了3种酶活性。N添加对3种酶活性影响较小(尤其2019年); 草木樨状黄耆(Astragalus melilotoides)生物量与脲酶和磷酸酶活性负相关。糙隐子草(Cleistogenes squarrosa)生物量与3种酶活性正相关。除Patrick丰富度指数外, 植物群落多样性指数普遍与3种酶活性负相关; 对酶活性影响较大的因子包括土壤pH、土壤全磷(P)含量和微生物生物量碳(C):N:P。因此, 短期内降水量变化及N添加对荒漠草原土壤酶的影响较小(尤其在减少降水量条件下); 降水量增加及N添加通过提高植物生物量、改变植物多样性、调节微生物生物量元素平衡以及增强土壤P有效性, 直接影响着土壤酶活性。鉴于土壤酶种类的多样化和功能的复杂性, 今后还需结合多种酶活性的长期变化规律, 深入分析全球变化对酶活性的影响机制。

关键词: 干旱半干旱区, 降水格局改变, 大气氮沉降增加, 微生物生态化学计量特征, 植物群落多样性

Abstract:

Aims Soil enzymes, which are mainly produced by plant roots and soil microbes, involve in the organic matter degradation and element cycling and other key processes in plant-soil systems. Study on the relationships between soil enzyme activity and plant community composition and microbial activity under changing precipitation pattern and increasing nitrogen (N) deposition can provide a new insight for evaluating the influencing mechanism of global change on the biogeochemical cycling in plant-soil systems.
Methods Based on a field experiment involving five precipitation treatments (50% reduction, 30% reduction, natural precipitation, 30% increase, and 50% increase) and two N addition treatments (0 and 5 g·m-2·a-1) conducted in a desert steppe of Ningxia since 2017, the changes of soil enzyme activities (sucrase, urease, and phosphatase) were studied and their relationships with plant community composition and microbial ecological stoichiometry were analyzed in 2018 and 2019.
Important findings Compared with decreasing precipitation, increasing precipitation had greater impacts on the three enzyme activities, but its effects were interacted with N addition and sampling year. Increasing precipitation had no significant impacts on the three enzyme activities in 2018, but enhanced them in 2019. By contrast, N addition had less influences on the three enzyme activities, especially in 2019. The biomass of Astragalus melilotoides was negatively correlated with urease and phosphatase activities, while the biomass of Cleistogenes squarrosa had positive correlation with the three enzyme activities. Except the Patrick richness index, plant community diversity indices were generally negatively correlated with the three enzyme activities. Soil enzyme activities were more greatly affected by soil pH, soil total phosphorus (P), and microbial biomass carbon (C):N:P. Therefore, short-term precipitation change and N addition have little effects on the soil enzymes in the studied desert steppe (especially under reducing precipitation); increasing precipitation and N addition could pose direct influences on soil enzyme activities by increasing plant biomass, changing plant diversity, regulating microbial biomass ecological stoichiometry, and enhancing soil P availability. Given the diversity and functional complexity of soil enzymes, it is necessary to deeply analyze the influencing mechanism of global change on enzyme activities by measuring the long-term responses of various enzyme activities.

Key words: arid and semi-arid region, changing precipitation regimes, increasing atmospheric nitrogen deposition, microbial ecological stoichiometry, plant community diversity