摘要
探明草地退化过程中土壤微生物量和酶的变化趋势及其化学计量学特征,对理解草地的退化机理有重要意义。本研究以青藏高原高寒草甸4种不同退化程度(未退化、轻度退化、中度退化、重度退化)草甸为研究对象,分析了土壤微生物量和酶化学计量学特征及其影响因素。结果表明,随草甸退化程度的加剧,土壤有机碳(Soil organic carbon,SOC)、全氮(Total nitrogen,TN)、速效钾(Available potassium,AK)、微生物量碳(Microbial biomass carbon,MBC)和微生物量氮(Microbial biomass nitrogen,MBN)含量显著降低;未退化草甸β-1,4-葡萄糖苷酶(β-1,4-Glucosidase,BG)和β-N-乙酰氨基葡萄糖苷酶(β-N-Acetylglucosaminidase,NAG)活性显著低于轻度、中度和重度退化;重度退化草甸土壤氮/磷、MBN/MBP显著低于未退化,ln(NAG+LAP)/lnALP取值范围为0.77~0.83,高于全球均值0.44,说明退化引起了该地区的土壤氮限制;相关分析表明微生物量和酶的化学计量比受有机碳和全氮的影响显著。综上,微生物量和酶的化学计量学特征对土壤养分变化响应敏感且能反映土壤养分限制情况。
Revealing the changes in soil microbial biomass and enzymes and their stoichiometric characteristics is of great significance to understand the degradation mechanism of degraded grassland.In the present study,we surveyed the soil in Qinghai-Tibetan alpine meadows and classified the extent of degradation as undegraded,lightly degraded,moderately degraded,and severely degraded to evaluate the changes in stoichiometric characteristics of microbial biomass and enzymes activities.Results showed that as the meadow degraded,the contents of soil organic carbon(SOC),total nitrogen(TN),available potassium(AK),microbial biomass carbon(MBC)and microbial biomass nitrogen(MBN)decreased significantly.Activities ofβ-1,4-Glucosidase(BG)andβ-N-Acetylglucosaminidase(NAG)of the degraded grasslands were significantly higher than that of the undegraded meadow.The ratios of N/P and MBN/MBP in severely degraded meadow were significantly lower than those in undegraded meadow,and ln(NAG+LAP)/lnALP ranged from 0.77 to 0.83,which was higher than the 0.44(global average value),indicating that the degradation aggravated the soil nitrogen limitation in the studied area.The correlation analysis showed soil microbial biomass,enzyme activities and ecological stoichiometric ratio were positively correlated with SOC and TN.In summary,soil microbial biomass,enzyme activities and ecological stoichiometric ratio were sensitive to soil nutrient change and could reflect soil nutrient limitations.
作者
喻岚晖
王杰
廖李容
张超
刘国彬
YU Lan-hui;WANG Jie;LIAO Li-rong;ZHANG Chao;LIU Guo-bin(Research Center of Soil and Water Conservation and Ecological Environment, Chinese Academy of Sciences and Ministry Education,Yangling, Shaanxi Province 712100, China;University of Chinese Academy of Sciences, Beijing 100049, China;Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi Province 712100, China)
出处
《草地学报》
CAS
CSCD
北大核心
2020年第6期1702-1710,共9页
Acta Agrestia Sinica
基金
中科院战略性先导专项(XDA20040200)
陕西省创新人才推进计划-青年科技新星项目(2019KJXX-081)
国家自然科学基金项目(41771554)共同资助。
关键词
高寒草甸
草地退化
微生物生物量
土壤酶
生态化学计量学
Alpine meadow
Grassland degradation
Microbial biomass
Soil enzyme
Ecological stoichiometric
