氮磷添加对亚热带常绿阔叶林凋落物产量及其养分含量的影响  

Effects of nitrogen and phosphorus additions on litterfall production and nutrient dynamics in evergreen broad-leaved forests

作　　者：赵晓雅 关梦冉 孙孟瑶 王泽夫[1] 徐小牛[1] ZHAO Xiaoya;GUAN Mengran;SUN Mengyao;WANG Zefu;XU Xiaoniu(School of Forestry&Landscape of Architecture,Anhui Agricultural University,Hefei 230036,China)

机构地区：[1]安徽农业大学林学与园林学院,安徽合肥230036

出　　处：《南京林业大学学报（自然科学版）》2020年第6期55-62,共8页Journal of Nanjing Forestry University：Natural Sciences Edition

基　　金：北京市自然科学基金项目(6172026)。

摘　　要：【目的】凋落物是森林净生产量的重要组分,探讨森林凋落物生产及其养分归还量对氮磷添加的响应,为亚热带常绿阔叶林可持续经营提供科学依据。【方法】选择安徽池州亚热带常绿阔叶林,包括甜槠(Castanopsis eyrei)老龄林和苦槠(C.sclerophylla)中龄林,开展氮磷添加试验,设置3个处理,即氮[N100 kg/(hm^2·a)]、氮+磷[N 100 kg/(hm^2·a)+P 50 kg/(hm^2·a)]和对照(CK,无氮磷添加)。采用凋落物收集框法,对林分凋落物生产量及其养分归还量进行了为期1年的监测(2017年5月至2018年4月)。【结果】N+P处理下,苦槠林和甜槠林总凋落物量最高值分别为9.502、7.120 t/(hm^2·a);其次是N处理,分别为8.393、7.041 t/(hm^2·a);CK林分分别为7.724和6.697 t/(hm^2·a),氮磷添加提高了总凋落物量,但不同处理间没有显著差异。在N处理和对照条件下,两林分凋落物各组分所占比例由大到小顺序均为:落叶、落枝、碎屑、落花落果。但在N+P处理的苦槠林中由大到小依次为:落叶、落枝、落花落果、碎屑。N处理下,苦槠林和甜槠林凋落物年均氮含量分别为14.199和13.648 g/kg,N+P处理分别为13.863和13.650 g/kg,CK林分分别为13.384和13.094 g/kg。各处理下苦槠林和甜槠林凋落物年均磷含量由大到小顺序为N+P、CK、N处理。两林分凋落物的氮磷含量和年归还量不同处理间差异均不显著;不同处理间的苦槠林和甜槠林凋落物的氮磷比均无明显差异。【结论】氮沉降提高了苦槠和甜槠林凋落物产量,磷添加具有一定的增效作用,表明磷添加缓解了氮沉降引起的磷限制作用。【Objective】Litterfall is an important component of net primary productivity of forests.This study deals with the response of litter production and nutrient return to nitrogen(N)and phosphorus(P)additions in subtropical evergreen broad-leaved forests to achieve a sustainable management of the forest.【Method】A simulated nitrogen deposition experiment was conducted in the evergreen broad-leaved Castanopsis eyrei forest and C.sclerophylla forest;the experiment was commenced from May 2017 to April 2018 in Chizhou,Anhui Province.The experimental design consisted of N[N,100 kg/(hm^2·a)],N+P[N 100 kg/(hm^2·a)+P 50 kg/(hm^2·a)]treatments,and a control(CK,stream water only without fertilizer).【Result】The annual litterfall productions of C.eyrei and C.sclerophylla forests were the highest in N+P treatment with 9.502 and 7.120 t/(hm^2·a),respectively,followed by N treatment with the annual litterfall of 8.393 and 7.041 t/(hm^2·a),respectively,and then CK with the annual litterfall of 7.724 and 6.697 t/(hm^2·a),respectively.There were no significant differences among the treatments.The percentage of the litterfall component was in the following order:foliage>branch>miscellaneous>sexual organs,while the percentage of the litterfall component was in the following order:foliage>branch>sexual organs>miscellaneous for N+P treatment in C.sclerophylla forests.The annual mean weighted N concentrations of litterfall were 14.199 and 13.684 g/kg for N treatment,13.863 and 13.650 g/kg for N+P treatment,13.384 and 13.094 g/kg for CK in C.sclerophylla and C.eyrei forests,respectively.The order of annual mean weighted P concentrations of litterfall was ranked as N+P>CK>N for the two forest stands and there was no significant difference among the treatments.Additionally,no significant difference was observed in annual returns of N,P,and ratios of N/P among treatments for the two forest stands.【Conclusion】The addition of N plus P had a synergistic effect on the litterfall production in subtropical evergreen broad-leaved

关 键 词：常绿阔叶林 凋落物量 氮磷添加 养分含量 养分归还量 甜槠 苦槠 

分 类 号：S714[农业科学—林学]