放牧强度对华北农牧交错带典型草地土壤化学计量特征的短期影响  

Short-term effects of grazing intensity on soil stoichiometric characteristics of typical grassland in the agro-pastoral ecotone of northern China

作　　者：郑慧 薛江博 桂建华 秦加敏 郝杰[1,2] 陈晓鹏 王常慧 董宽虎[1,2] ZHENG Hui;XUE Jiang-bo;GUI Jian-hua;QIN Jia-min;HAO Jie;CHEN Xiao-peng;WANG Chang-hui;DONG Kuan-hu(College of Grassland Science,Shanxi Agricultural University,Jinzhong 030801,Shanxi,China;Youyu Loess Plateau Grassland Ecosystem Research Station of Shanxi Province,Youyu 037200,China;State Key Laboratory of Vegetation and Environmental Change,Institute of Botany,Chinese Academy of Sciences,Beijing 100093,China)

机构地区：[1]山西农业大学草业学院,山西晋中030801 [2]山西右玉黄土高原草地生态系统定位观测研究站,山西右玉037200 [3]中国科学院植物研究所植被与环境变化国家重点实验室,北京100093

出　　处：《应用生态学报》2021年第7期2433-2439,共7页Chinese Journal of Applied Ecology

基　　金：国家重点研发计划项目(2016YFC0500703);国家自然科学基金项目(31872406)资助。

摘　　要：放牧是天然草地的主要利用方式之一,不同放牧强度可能通过影响家畜的选择性采食、凋落物输入和微生物的组成及结构等影响草地土壤化学计量特征。本研究通过在华北农牧交错带典型草地一个连续3年(2017—2019年)的生长季放牧试验,测定了土壤全碳(TC)、全氮(TN)、可溶性有机碳(DOC)和可溶性氮(DN)含量,以及土壤微生物生物量碳(MBC)和微生物生物量氮(MBN),分析这些参数间的化学计量特征,研究放牧强度对该地区草地土壤计量化学特征的影响。结果表明:连续3年不同强度的放牧(1、2、4 sheep·0.2 hm^(-2))对土壤TC含量没有显著影响,2019年中度放牧显著降低了10~20 cm土层中TN含量,轻度、中度和重度放牧显著提高10~20 cm层土壤的C/N。连续3年不同强度的放牧对土壤DOC、DN含量以及DOC/DN均没有显著影响,而DOC和DN含量在2019年呈现出随放牧强度增加而减少的趋势,表明持续高强度的放牧可能会引起土壤可溶性养分减少。随着放牧年限的增长,轻度放牧显著增加了土壤MBC,重度放牧显著降低了土壤MBC,而土壤MBN及MBC/MBN在不同放牧强度下变化不显著。Grazing is the dominant land use way for natural grasslands.Different grazing intensities could affect soil stoichiometry in grasslands by influencing the selective feeding by livestock,litter input,and microbial community structure.In this study,a grazing experiment was carried out in a grassland of agro-pastoral ecotone in Northern China for three years(2017-2019).The concentrations of total carbon(TC),total nitrogen(TN),dissolved organic carbon(DOC),dissolved nitrogen(DN),microbial biomass carbon(MBC),and microbial biomass nitrogen(MBN)in soils were measured.We analyzed the stoichiometric characteristics of those parameters.The results showed that different grazing intensities(1,2,4 sheep·0.2 hm^(-2))had no significant effect on soil TC after three years.The moderate grazing intensity significantly reduced soil TN in 10-20 cm layer in 2019.The light,moderate,and heavy grazing intensities significantly increased soil C/N at 10-20 cm layer,while grazing intensities did not affect soil DOC,DN and DOC/DN.The soil DOC and DN content showed a decreasing trend with the increase of grazing intensity in 2019.It indicated that continuous high intensity grazing might reduce soil dissolved nutrients.The light grazing inten-sity increased soil MBC,while heavy grazing intensity reduced soil MBC significantly,with the increase of grazing year.Different grazing intensities did not affect soil MBN and MBC/MBN.

关 键 词：放牧强度 农牧交错带 土壤碳氮比 微生物生物量 

分 类 号：S812.2[农业科学—草业科学]