细根性状对土壤养分有效性的直接影响与机制——以亚热带杉阔混交林为例  

The direct effect and mechanism of fine root traits on soil nutrient availability:A case study of subtropical Chinese fir and broad-leaved mixed forest

作　　者：金朝斌 魏晓梦 徐海东 庞丹波 王聪 申卫军 JIN Chao-bin;WEI Xiao-meng;XU Hai-dong;PANG Dan-bo;WANG Cong;SHEN Wei-jun(College of Forestry,Guangxi University,Guangxi Key Laboratory of Forest Ecology and Conservation,State Key Laboratory of Conservation and Utilization of Biological Resources in Subtropical Agriculture,Nanning,Guangxi 530004,China;Changsha Research Station for Agricultural and Environmental Monitoring,Key Laboratory of Agro-ecological Processes in Subtropical Region,Institute of Subtropical Agriculture,Chinese Academy of Sciences,Changsha,Hunan 410125,China;College of Natural Resources and Environment,Northwest A&F University,Yangling,Shaanxi 712100,China;Shandong Key Laboratory of Eco-Environmental Science for the Yellow River Delta,Shandong University of Aeronautics,Binzhou Shandong,256600,China;School of Ecology and Environment,Ningxia University,Yinchuan,Ningxia 750021,China)

机构地区：[1]广西大学林学院,广西森林生态与保育重点实验室,亚热带农业生物资源保护与利用国家重点实验室,广西南宁530004 [2]长沙农业环境监测研究站,中国科学院亚热带农业生态过程重点实验室,中国科学院亚热带农业生态研究所,湖南长沙410125 [3]西北农林科技大学资源环境学院,陕西杨凌712100 [4]山东省黄河三角洲生态环境科学重点实验室,山东航空学院,山东滨州256600 [5]宁夏大学生态环境学院,宁夏银川750021

出　　处：《农业现代化研究》2024年第3期520-530,共11页Research of Agricultural Modernization

基　　金：国家自然科学基金项目(42107369,32271847);广西森林生态与保护重点实验室开放基金(20221204);广西科技计划项目(AD20238040,AD23026326)。

摘　　要：细根性状对土壤养分有效性的影响由微生物介导或由细根与土壤的直接互作而发生,然而前者受到了大量关注,后者却鲜有报道。本研究以亚热带杉阔混交林中6个混交树种(资源获取和资源保守型各3种)为研究对象,采用原位网袋试验,研究了细根对土壤氮、磷有效性的直接、间接和总体效应,及其与细根性状的关系。结果显示,在两种资源利用策略下,细根与土壤直接接触均能提高土壤氮和磷的有效性;获取型树种对土壤磷的影响更为显著,表现为更强的直接、间接和总体效应,而保守型树种对土壤氮的间接效应更强。细根碳氮比是调控其对土壤氮、磷有效性影响的首要因素。资源利用策略对氮有效性的直接影响差异主要取决于对养分摄取的强弱,间接影响则由有机氮矿化主导。低碳氮比的细根提高了磷有效性,该影响通过产生更多的磷酸酶直接产生,或通过降低土壤pH而间接实现。本研究丰富了细根性状对土壤养分有效性的调控机制,并为杉阔混交林伴生树种选择提供了理论支撑。The effect of fine root traits on soil nutrient availability is mediated by microorganisms or by direct interaction between fine roots and soil.However,the former has received a lot of attention,while the latter has rarely been reported.In this study,six mixed tree species(3 resource-acquisitive and 3 resource-conservative)in a subtropical Chinese fir-broadleaf mixed forest were used as the research object.The direct,indirect,and overall effects of fine roots on soil nitrogen and phosphorus availability and the relationship between fine root traits and them were studied by an in-situ net bag test.The results showed that fine root direct contact with soil could improve the availability of soil N and P under both resource utilization strategies.The effect of acquisitive tree species on soil phosphorus was more significant,showing stronger direct,indirect,and overall effects,while the indirect effect of conservative tree species on soil nitrogen was stronger.Moreover,the C/N ratio of fine roots is the primary factor regulating its effect on soil N and P availability.The direct effect of resource utilization strategies on nitrogen availability mainly depends on the strength of nutrient uptake,and the indirect effect is dominated by organic nitrogen mineralization.Fine roots with a low C/N ratio directly promote P availability by producing more phosphatases or indirectly promote P availability by reducing soil pH.This study enriched the regulatory mechanism of fine root traits on soil nutrient availability and provided theoretical support for the selection of associated tree species in mixed forests.

关 键 词：细根性状 资源利用策略 直接效应 土壤氮有效性 土壤磷有效性 酶活性 

分 类 号：S714.2[农业科学—林学]