Page 144 - 《广西植物》2023年第5期
P. 144

9 2 4                                  广  西  植  物                                         43 卷
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                                WU Dan ꎬ WEN Chen ꎬ WEI Wei ꎬ ZHANG Qindi
               ( 1. College of Life Sciencesꎬ Shanxi Normal Universityꎬ Taiyuan 030031ꎬ Chinaꎻ 2. State Key Laboratory of Urban and Regional Ecologyꎬ
                          Research Center for Eco ̄Environmental Sciencesꎬ Chinese Academy of Sciencesꎬ Beijing 100085ꎬ China )

                 Abstract: Soil nutrients and their stoichiometric characteristics are effective ways to evaluate the effect of vegetation
                 restoration in small watersheds on the Loess Plateau. The study aims to analyze different soil depths(0-20 cm、20-40
                 cm、40-60 cm) of Stipa bungeana communityꎬ Leymus secalinus communityꎬ Medicago sativa communityꎬ Caragana
                 korshinskii communityꎬ and Armeniaca sibirica community in three restoration types (natural grassꎬ natural restorationꎬ
                 manual restoration). The vertical variation characteristics of soil organic carbon (SOC)ꎬ total nitrogen (TN)ꎬ total
                 phosphorus (TP)ꎬ total potassium (TK) contents. Their ecological stoichiometry was analyzed utilizing variance analysis
                 and linear regressionꎬ and the coupling relationship among each index was discussed. The results were as follows: (1)
                 Soil SOCꎬ TNꎬ TP contents were affected by different communitiesꎬ and soil depth affected soil SOCꎬ TNꎬ TP and TK
                 contentsꎬ but only TN content was affected by their interaction. In the 0-20 cm soil layerꎬ soil SOC and TN contents in
                 Caragana korshinskii shrub were significantly higher than those in other communities (P<0.05). (2) In the vertical soil
                 profileꎬ except for C ∶ Nꎬ the soil stoichiometric ratios decreased gradually with soil depth deepening. In the soil layers
                 of 0-20 cm and 20-40 cmꎬ except for the soil C ∶ N which was the highest in Leymus secalinus community (P<0.05)ꎬ
                 the soil C ∶ Pꎬ N ∶ P and N ∶ K were all the highest in Caragana korshinskii communityꎻ In the 40-60 cm soil layerꎬ
                 the soil C ∶ K of the Armeniaca sibirica community was significantly lower than other communities (P<0.05). (3) Soil
                 SOCꎬ TNꎬ TP and TK contents were positively correlated under different communities. Among themꎬ SOC and TN
                 contentsꎬ TN and TP contentsꎬ SOC and TP contentsꎬ TN and TK contents reached significant levels in the five
                 communities (P<0.05). In different communitiesꎬ there was a significant positive correlation between soil C ∶ P and
                 C ∶ Kꎬ C ∶ K and N ∶ Kꎬ N ∶ P and N ∶ K (P<0.05)ꎬ while there was a negative correlation between C ∶ N and N ∶ Pꎬ
                 C ∶ N and N ∶ Kꎬ P ∶ K and C ∶ Pꎬ P ∶ K and N ∶ P. To sum upꎬ soil SOCꎬ TNꎬ TP and TK contents in different
                 communities gradually decrease with the soil depth deepening. The comprehensive ecological stoichiometry characteristics
                 of the Caragana korshinskii community are more substantialꎬ more conducive to improving the local soil quality.
                 Key words: loess watershedꎬ vegetation restorationꎬ soil nutrientꎬ vertical distributionꎬ ecological stoichiometry



                土壤是陆地生态系统的主要组成部分ꎬ同时                                近年来ꎬ陆地生态系统中关于不同植物群落
            也是植物生长发育所需养分的重要来源ꎬ影响着                              和不同恢复方式下 C、N、P、K 的生物地球化学循
            植物群落的组成、稳定及演替(Zeng et al.ꎬ 2017)ꎮ                  环和 生 态 化 学 计 量 特 征 的 研 究 受 到 广 泛 关 注
            碳(C)、氮(N)、磷( P)、钾( K) 元素是土壤中的关                     (Chen et al.ꎬ 2012ꎻWang et al.ꎬ 2014)ꎮ 周萍等
            键营养元素ꎬ影响着植物生长、凋落物分解及土壤                             (2008)研究发现植物群落组成影响土壤养分和有
            养分积累与循环( Griffiths et al.ꎬ 2012)ꎮ 此外ꎬ土             机质含量及分布ꎬ不同群落的根系深浅不同ꎬ对土
            壤营养元素的动态和演变在生态过程中是相互作                              壤养分的吸收强度和深度有所不同ꎮ 植物类型对
            用和耦合的( Tian et al.ꎬ 2010ꎻ陶冶等ꎬ2016)ꎬ元               不同元素的选择吸收也不同ꎬ从而导致不同群落
            素间的比例关系是反映生态系统结构和功能的重                              的土壤养分在垂直剖面上存在差异( 朱秋莲等ꎬ
            要指标( Liu et al.ꎬ 2017)ꎮ 生态化学计量学是研                  2013)ꎮ 薛箑等(2007) 研究发现黄土丘陵区纸坊
            究生态系统中营养元素的分布、循环、限制和平衡                             沟流域人工柠条林和刺槐林土壤 C 含量和 N 含量
            的重要方法( Elser et al.ꎬ 2000ꎻ贺金生等ꎬ2010ꎻ               高于天然草地ꎬ人工乔灌木林对土壤的改善作用
            Fang et al.ꎬ 2017)ꎬ采用其原理与手段研究土壤特                   优于天然草地ꎮ 另一些研究则认为ꎬ虽然人工恢
            征ꎬ可为评价土壤质量、阐明养分有效性提供建设                             复植被在一定范围内能改善土壤质量ꎬ但其改善
            性依据ꎬ对揭示陆地生态系统中土壤营养元素的                              作用比天然植被弱ꎮ 王国梁等(2002) 研究发现人
            循环和平衡机制具重要意义ꎮ                                      工种植的乔灌木林对 0 ~ 40 cm 土壤养分的提高作
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