氮磷添加对亚热带森林粗木质残体分解初期养分及化学计量特征的影响  

Effects of Nitrogen and Phosphorus Addition on Nutrient and Stoichiometric Characteristics of Coarse Woody Debris in Subtropical Forests During Early Decomposition

作　　者：徐乾 郑裕雄 何鲜 马龙龙 赵杼祺 冀翔宇 岳超 胡振宏 XU Qian;ZHENG Yu-xiong;HE Xian;MA Long-long;ZHAO Zhu-qi;JI Xiang-yu;YUE Chao;HU Zhen-hong(Key Laboratory of Green and Low-carbon Agriculture in Dryland of Northwest China,Ministry of Agriculture and Rural Affairs,College of Resources and Environment,Northwest Agriculture&Forestry University,Yangling 712100,China;State Key Laboratory of Soil Erosion and Dryland Agriculture on the Loess Plateau,Institute of Soil and Water Conservation,Northwest Agriculture&Forestry University,Yangling 712100,China;State Key Laboratory of Soil Erosion and Dryland Agriculture on the Loess Plateau,Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources,Yangling 712100,China)

机构地区：[1]西北农林科技大学资源环境学院农业农村部西北旱地农业绿色低碳重点实验室,陕西杨凌712100 [2]西北农林科技大学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 [3]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

出　　处：《土壤通报》2023年第6期1418-1428,共11页Chinese Journal of Soil Science

基　　金：国家自然科学基金(41903070);广东省基础与应用基础研究基金项目(2022A1515010663);中国高校基础研究基金(2452021127);陕西省气象局秦岭和黄土高原生态环境气象重点实验室开放基金课题(2020K-7,2021K-7)资助。

摘　　要：【目的】明确树种属性和养分添加对亚热带森林粗木质残体分解养分含量及化学计量的影响,为森林养分管理和碳循环提供理论依据。【方法】在浙江天童野外观测研究站森林选取6种典型树种粗木质残体,通过开展野外氮(N)磷(P)添加试验,设置对照(CK,蒸馏水)、氮添加(N,100 kg hm^(-2)a^(-1))、磷添加(P,15 kg hm^(-2)a^(-1))和氮+磷添加(N+P,N100 kg hm^(-2)a^(-1)+P15 kg hm^(-2)a^(-1))4种处理,测定粗木质残体分解初期(3年)N、P养分含量和生态化学计量比,分析树种属性和外源养分添加对粗木质残体养分含量和化学计量比的影响。【结果】与初始养分含量相比,分解三年后,CK处理的被子树种N、P含量显著增加,C/N显著降低,裸子树种P含量显著降低(P<0.05)。与CK相比,P和N+P添加处理显著增加了裸子树种P含量,增加幅度分别为57.29%和53.79%;N+P添加处理显著降低了裸子树种碳(C)含量、C/N、C/P,降低幅度分别为24.0%、30.58%和44.91%(P<0.05)。N+P添加处理对被子树种养分含量及化学计量比无显著影响。主成分分析表明,N+P添加处理对裸子树种C、N、P含量及其化学计量比的影响大于被子树种,P元素是影响粗木质残体养分及化学计量特征的主要因素。分解三年后粗木质残体的养分含量和初始密度显著正相关,而与初始C含量显著负相关。【结论】总体而言,由于粗木质残体养分含量和物理性质的差异,被子和裸子树种粗木质残体养分含量和化学计量比对氮磷添加的响应存在明显差异,其中初始养分含量较低的裸子树种粗木质残体养分含量及化学计量比受氮磷添加的影响较大。因此,未来研究气候变化(如氮磷沉降)对森林养分库和有机碳分解影响时应考虑粗木质残体树种属性的差异。[Objective]The paper aimed to investigate the effects of tree species traits and nutrient addition on the nutrient contents and stoichiometric ratios of coarse woody debris decomposition in subtropical forests,and to provide a theoretical basis for forest nutrient management and carbon(C)cycling.[Methods]Six typical tree species were selected from the forest of Tiantong Field Observation and Research Station in Zhejiang Province.The field experiment of nitrogen(N)and phosphorus(P)addition included four treatments:control(CK,distilled water),N addition(N,100 kg hm^(-2)a^(-1)),P addition(P,15 kg hm^(-2)a^(-1))and N+P addition(N+P,100 kg hm^(-2)a^(-1)+15 kg hm^(-2)a^(-1)).The nutrient contents and stoichiometric ratios of coarse woody debris were determined to analyze the effects of tree species traits and exogenous nutrient addition on endogenous nutrient contents and stoichiometric ratios at the initial stage of decomposition(3 years).[Results]Compared with the initial nutrient content,after three years of decomposition,the treatment of CK significantly increased N,P concentrations and decreased C/N under angiosperms,while P content was significantly decreased under gymnosperms(P<0.05).Compared with CK,P and N+P addition significantly increased the P content of gymnosperms by 57.29% and 53.79%,respectively.N+P addition significantly decreased the C content,C/N and C/P of gymnosperms by 24.0%,30.58% and 44.91%(P<0.05),respectively.N and P addition had no significant effects on the nutrient content and stoichiometric ratio of angiosperms.Principal component analysis showed that the effects of N and P addition on the contents of C,N and P and their stoichiometric ratios of gymnosperms were greater than those of angiosperms,and P element was the main factor affecting the nutrient and stoichiometric characteristics of coarse woody debris.After three years of decomposition,the nutrient content of coarse woody debris was positively correlated with the initial density,but negatively correlated with the initial C content.[

关 键 词：粗木质残体 树种属性 氮磷添加 养分含量 化学计量 

分 类 号：S713[农业科学—林学]