摘要
林分密度是影响人工林生态系统结构和功能的关键因素,其对土壤结构与养分循环的调控作用直接关系到森林的生产力与生态服务功能。为探究刺槐人工林密度对土壤稳定性和养分含量的影响,本研究在山西吉县蔡家川流域选取5种密度(800~1100、1100~1400、1400~1700、1700~2000、2000~2300株·hm^(-2))的刺槐林,测定0~10 cm表层和10~20 cm亚表层土壤的团聚体组成及养分含量特征。结果表明:当林分密度从800~1100株·hm^(-2)增加至2000~2300株·hm^(-2)时,土壤团聚体稳定性降低,养分含量下降,其中表层土壤大团聚体比例、平均重量直径(MWD)、几何平均直径(GMD)分别下降了2.3%、33.0%、19.4%,亚表层土壤分别下降了10.9%、25.3%、24.2%,分形维数(D)无明显变化规律。随林分密度增加,全氮(TN)、有机碳(SOC)含量总体呈下降趋势,全磷(TP)含量无明显变化规律;0.25~1 mm粒径团聚体TN、TP、SOC含量最高。表层土壤MWD、GMD、TN、TP和SOC含量显著高于亚表层。林分密度与土层的交互作用对GMD有显著负向影响,对D有极显著正向影响,二者共同解释了60.1%的土壤团聚体稳定性变异;TN含量与GMD呈显著正相关,与D呈显著负相关。本试验条件下800~1100株·hm^(-2)密度可有效维持刺槐林土壤结构稳定与碳氮固存。
Stand density is a key factor influencing forest structure and function.Its regulatory effects on soil structure and nutrient cycling are directly related to forest productivity and ecosystem functions.To investigate the effects of stand density of Robinia pseudoacacia plantation on soil stability and nutrient content,we selected stands with five density gradients(800-1100,1100-1400,1400-1700,1700-2000,2000-2300 plants·hm^(-2))in the Cai-jiachuan watershed of Ji County,Shanxi Province.The composition of soil aggregates and nutrient characteristics in the topsoil(0-10 cm)and subsurface layers(10-20 cm)were determined.The results showed that soil aggregate stability decreased and nutrient content declined as stand density increased from 800-1100 to 2000-2300 plants·hm^(-2).In the topsoil layer,the proportion of macroaggregates,mean weight diameter(MWD),and geometry mean diameter(GMD)decreased by 2.3%,33.0%,and 19.4%,respectively.In the subsurface layer,they decreased by 10.9%,25.3%,and 24.2%,respectively.The fractal dimension(D)showed no change.Total nitrogen(TN)and organic carbon(SOC)contents generally decreased with increasing stand density,but no significant trend was observed in the total phosphorus(TP)content.The aggregates with 0.25-1 mm size fraction had the highest contents of TN,TP,and SOC.The MWD,GMD,TN,TP,and SOC content in the topsoil were significantly higher than that in the subsurface soil.The interaction between stand density and soil layer had a significant negative effect on GMD,and a highly significant positive effect on D,collectively explaining 60.1%of the variation in soil aggregate stability.TN content was significantly positively correlated with GMD and negatively correlated with D.The stand density of 800-1100 plants·hm^(-2) could effectively maintain soil structural stability and carbon and nitrogen sequestration.
作者
刘瑞
赵藤彦
马淑敏
唐洁
凌喜乐
梁文俊
魏曦
LIU Rui;ZHAO Tengyan;MA Shumin;TANG Jie;LING Xile;LIANG Wenjun;WEI Xi(College of Forestry,Shanxi Agricultural University,Jinzhong 030801,Shanxi,China)
出处
《应用生态学报》
北大核心
2026年第1期73-81,共9页
Chinese Journal of Applied Ecology
基金
国家自然科学基金项目(32371970,31901365,31971644)资助。
关键词
刺槐
林分密度
养分含量
团聚体稳定性
Robinia pseudoacacia
stand density
nutrient content
aggregate stability
