摘要
【目的】探究华西雨屏区不同林龄柳杉人工林根际与非根际土壤微生物生物量碳氮含量、活性氮含量和氮矿化速率的差异,为该区域柳杉人工林土壤氮素管理提供理论支持。【方法】以华西雨屏区中龄林(13 a)、成熟林(33 a)和过熟林(53 a)的柳杉人工林为研究对象,采集根际土和非根际土壤样品,测定微生物生物量碳、氮含量及氮矿化速率等指标。【结果】(1)柳杉成熟林根际土微生物生物量碳、氮含量整体显著高于中龄林和过熟林阶段,非根际土微生物生物量碳、氮含量随林龄增加呈降低趋势,而根际与非根际土微生物生物量碳氮比值均随林龄增加呈增加的趋势。(2)成熟林根际土与非根际土的铵态氮含量、铵态氮与硝态氮比值整体均显著高于中龄林和过熟林,而土壤硝态氮和无机氮含量随林龄增加均呈降低趋势,并且根际土铵态氮、硝态氮以及无机氮含量整体均高于非根际土。(3)成熟林根际土铵化速率及其根际效应显著高于其他林龄阶段;中龄林和成熟林根际土与非根际土的硝化速率和净氮矿化速率整体显著高于过熟林,并且根际土的硝化速率和净氮矿化速率整体均高于非根际土。(4)柳杉人工林土壤微生物生物量碳、氮含量和氮矿化速率与土壤理化性质密切相关。【结论】相较于中龄林和过熟林,柳杉成熟林根际土壤表现出更快的氮循环速率和更高的氮素有效性。因此,适当加强柳杉中龄林和过熟林氮肥管理可能更有利于提高柳杉人工林质量。
【Objective】Exploring the differences of microbial biomass carbon and nitrogen concentra-tion,active nitrogen concentration and nitrogen mineralization rate in rhizosphere and bulk soil of Crypto-meria japonica var.sinensis plantations of different ages in the Rainy Area of Western China to provide theoretical support for nitrogen management of C.japonica var.sinensis plantations in this region.【Method】Taking the C.japonica var.sinensis plantations of middle-aged forests(13 a),mature forests(33 a)and over-mature forests(53 a)in the Rainy Area of Western China as the research objects,samples were collected from root rhizosphere and bulk soil to determine a range of indexes such as soil mi-crobial biomass carbon,nitrogen concentration as well as nitrogen mineralization rates.【Result】①The carbon and nitrogen concentration of microbial biomass in root rhizosphere of C.japonica var.sinensis plantations of mature stages overall significantly higher than those in middle and over-mature stages.The carbon and nitrogen concentration of microbial biomass in bulk soil showed a decreasing trend with in-creasing stand age,while the microbial biomass carbon-to-nitrogen ratio in both root rhizosphere and bulk soil showed an increasing trend with increasing stand age.②The ammonium nitrogen concentration and the ratio of ammonium nitrogen to nitrate nitrogen in the root rhizosphere and bulk soils of mature for-ests were significantly higher than those of middle and over-mature forests.Both nitrate nitrogen and inor-ganic nitrogen concentration tended to decrease with increasing age.Moreover,the overall ammonium ni-trogen,nitrate nitrogen and inorganic nitrogen concentration in the root rhizosphere soils were higher than those in the bulk soils.③The rate of ammonification and its rhizosphere effect were significantly higher in the bulk soils of mature forests than in other forest age stages;the rates of nitrification and net nitrogen mineralization in the root rhizosphere and bulk soils of middle and mature forests were signifi-cantly higher overall than in over-mature forests,and the rates of nitrification and net nitrogen mineral-ization in the root rhizosphere soils were higher overall than in the bulk soils.④The carbon and nitrogen concentration of soil microbial biomass and the rate of nitrogen mineralization in Cryptomeria japonica var.sinensis plantations are closely related to soil physicochemical properties.【Conclusion】Compared to middle aged and over-mature stands,mature stands of C.japonica var.sinensis plantations show rapid turnover and higher effectiveness of root rhizosphere nitrogen.Therefore,it may be more beneficial to im-prove the quality of C.japonica var.sinensis plantations by appropriately enhancing the management of nitrogen fertilization in middle and over-mature stands.
作者
刘春燃
李婧
简毅
李晗
谭波
徐振锋
游成铭
LIU Chunran;LI Jing;JIAN Yi;LI Han;TAN Bo;XU Zhenfeng;YOU Chengming(Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province/National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River/Long-Term Research Station of Alpine Forest Ecosystems/College of Forestry,Sichuan Agricultural University,Chengdu 611130,China;Sichuan Academy of Forestry/Ecological Restoration and Conservation for Forest and Wetland Key Laboratory of Sichuan Province,Chengdu 610081,China)
出处
《四川农业大学学报》
CSCD
北大核心
2024年第4期836-846,共11页
Journal of Sichuan Agricultural University
基金
国家自然科学基金(32071745、31870602、31901295)
中国博士后科学基金(2022M722297)。
关键词
华西雨屏区
柳杉人工林
林龄
微生物生物量碳氮
氮矿化
Rainy Area of Western China
Cryptomeria japonica var.sinensis plantation
stand age
microbial biomass carbon and nitrogen concentration
nitrogen mineralization
