苔藓结皮及其下层土壤的胞外酶活性与微生物CUE特征  

Extracellular Enzyme Activities and Microbial CUE Characteristics of Mossy Crust and Soil Substratum

作　　者：张尚鹏 王百群[1,2] 晁赫嵘 王雨涵 ZHANG Shangpeng;WANG Baiqun;CHAO Herong;WANG Yuhan(State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Soil and Water Conservation,Chinese Academy of Sciences,Ministry of Water Resources,Yangling,Shaanxi 712100,China;University of Chinese Academy of Sciences,Beijing 100049,China;College of Natural Resources and Environment,Northwest A&F University,Yangling,Shaanxi 712100,China)

机构地区：[1]中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨凌712100 [2]中国科学院大学,北京100049 [3]西北农林科技大学资源环境学院,陕西杨凌712100

出　　处：《水土保持研究》2022年第2期106-111,共6页Research of Soil and Water Conservation

基　　金：国家自然科学基金(41561144011,40301024)。

摘　　要：为进一步明确苔藓结皮对下层土壤养分的影响及微生物对养分的利用特征,以黄土丘陵区典型退耕地上发育的苔藓结皮及其下层土壤(0—2 cm,2—5 cm,10—20 cm)为研究对象,分析在剖面尺度下土壤碳(C)、氮(N)、磷(P)养分状况、胞外酶活性以及微生物CUE特征。结果表明:苔藓结皮显著提高了表层土壤养分含量,结皮层的SOC,TN,TP,DOC,DON和Olsen-P含量分别是10—20 cm土壤养分的2.58,2.34,1.13,2.30,4.30,7.36倍。与养分含量特征一致,微生物生物量随土层深度的增加逐渐降低。在整个剖面尺度上,微生物群落存在较为稳定的元素内稳态以保持自身C,N,P的计量平衡。参与C,N,P循环的相关胞外酶活性在剖面尺度上表现出差异,β-1,4-葡萄糖苷酶(BG)随深度增加逐渐降低,而β-1,4-N-乙酰氨基葡萄糖苷酶(NAG)和碱性磷酸酶(AP)则表现为先降低后增加的趋势,底层土壤较高的NAG和AP酶活性反映出N,P养分的匮乏。微生物CUE在剖面尺度上表现为先降低后增加的趋势,平均水平为0.25,表明表层与深层土壤更有助于C的固存。此外,方差分解(VPA)和线性模型结果均指出养分状况和土壤酶是影响微生物CUE的关键因素。总的来说,苔藓结皮对表层土壤的养分和微生物代谢产生积极作用,尽管底层土壤养分匮乏,但仍保持较高的微生物C利用效率。To further clarify the influence of mossy crust on nutrients and the characteristics of microbial utilization of nutrients in soil substratum,the mossy crust and its soil substratum(0—2 cm,2—5 cm,10—20 cm)developed on the typical abandoned cropland in the loess hilly region were selected as the research samples,the status of carbon(C),nitrogen(N),phosphorus(P),extracellular enzyme activities and microbial CUE characteristics were analyzed.The results showed that the moss crust significantly improved the nutrient status of surface soil,and the contents of SOC,TN,TP,DOC,DON and Olsen-P in the crust layer were 2.58,2.34,1.13,2.30,4.30 and 7.36 times of those in 10—20 cm soil layer,respectively.Consisting with the characteristics of nutrient contents,the microbial biomass decreased gradually with the increase of soil depth.In the whole soil profile,the microbial community had a relatively stable element homeostasis to maintain its C,N,P equilibrium.The extracellular enzyme activities involved in C,N,and P cycles were significantly different in different soil depths.β-1,4-glucosidase(BG)decreased with increase of soil depth,whileβ-1,4-N-acetylglucosaminosidase(NAG)and alkaline phosphatase(AP)showed a trend of decreasing first and increasing afterwards.The higher activities of NAG and AP in the soil substratum reflected the deficiency of N and P.Microbial CUE decreased at first and increased afterwars along the soil profile,with an average level of 0.25,reflecting that the habitat was more conducive to C sequestration in surface and deep soil.In addition,the results of variance decomposition(VPA)and linear model indicated that nutrient status and soil enzymes were the key factors affecting microbial CUE.In general,in different soil depths,mossy crusts have a positive effect on the nutrients and microbial metabolism of the topsoil,and the soil substratum maintains a high microbial C utilization efficiency despite the insufficiency of nutrients.

关 键 词：苔藓结皮 剖面 养分 胞外酶活性 微生物碳利用效率 

分 类 号：S154.1[农业科学—土壤学] S158.2[农业科学—农业基础科学]