氮添加对滇中高原森林凋落物养分残留及其持水性的影响  

Influence of Nitrogen Addition on Nutrient Residues and Water Holding Capacity of Forest Litter in Central Yunnan Plateau,China

作　　者：肖文贤 宋娅丽[1,2] 王克勤 安文雄[1] 苏孟白 XIAO Wenxian;SONG Yali;WANG Keqin;AN Wenxiong;SU Mengbai(College of Ecology and Environment,Southwest Forestry University,Kunming 650224;Yuxi Forestry Ecosystem Research Station of National Forestry and Grassland Administration,Kunming 650224)

机构地区：[1]西南林业大学生态与环境学院,昆明650224 [2]国家林业和草原局云南玉溪森林生态系统国家定位观测研究站,昆明650224

出　　处：《水土保持学报》2023年第3期319-329,共11页Journal of Soil and Water Conservation

基　　金：云南省教育厅科学研究基金项目(2022J0510);国家自然科学基金项目(30660037);云南省科技厅“三区”人才支持计划项目(90202101);云南省自然生态监测网络云南玉溪森林生态站运行项目(2022-YN-13);云南玉溪森林生态系统国家长期科研基地项目(2020132550)。

摘　　要：为揭示森林生态系统养分循环和水分循环对氮沉降的响应机制,以滇中高原华山松(Pinus armandii)和云南松(Pinus yunnanensis)为研究对象,开展野外氮添加下凋落叶、枝原位分解研究试验,设置对照[N 0 g/(m^(2)·a),CK]、低氮[N 10 g/(m^(2)·a),LN]、中氮[N 20 g/(m^(2)·a),MN]和高氮[N 25 g/(m^(2)·a),HN]共4个处理,利用尼龙网袋法和室内浸泡法,探究凋落叶、枝养分元素残留率、持水量和持水率及吸水速率对氮添加的响应。结果表明:(1)随着分解时间的持续,2种林分凋落叶、枝碳(C)、氮(N)、磷(P)分别呈释放、富集—释放、富集过程,凋落叶C、N、P残留率显著小于凋落枝(p<0.05);(2)凋落叶最大持水量和最大吸水速率显著大于凋落枝(p<0.05),分解24个月时,与CK相比,LN处理下2种林分凋落叶、枝C,华山松凋落叶N残留率降低1.98%~7.27%,10.79%,HN处理下2种林分凋落叶、枝C,华山松凋落叶、枝和云南松凋落枝N,华山松凋落枝P残留率则增加4.26%~9.08%,11.94%~44.51%,42.42%;(3)分解24个月时,与CK相比,LN、MN和HN处理华山松凋落叶、枝和云南松凋落叶最大持水量和最大吸水速率分别降低11.44%~25.24%,5.81%~32.23%,云南松凋落枝则增加15.48%~24.26%,17.97%~23.74%。(4)2种林分凋落叶、枝持水量随浸泡时间延长而增加,而吸水速率则为降低,持水量与浸泡时间的关系均呈对数函数关系(m=a+blnt),吸水速率与浸泡时间的关系呈幂函数关系(v=at^(-b))。(5)C与云南松凋落枝持水性呈正相关关系(p<0.05),N与华山松凋落枝、P与华山松和云南松凋落叶持水性呈负相关关系(p<0.05)。综上,氮添加通过改变凋落物分解过程中C、N、P养分元素残留特征进而影响其持水性。In order to reveal the response mechanism of nutrient cycling and water cycling to nitrogen deposition in forest ecosystem,we conducted a study on a situ decomposition of leaf and twig litters of Pinus armandii forest and Pinus yunnanensis forest in the middle Yunnan Plateau.Four treatments were set up:control(N 0 g/(m^(2)·a),CK),low nitrogen(N 10 g/(m^(2)·a),LN),medium nitrogen(N 20 g/(m^(2)·a),MN)and high nitrogen(N 25 g/(m^(2)·a),HN).Nylon mesh bag method and laboratory soaking method were used.The response of nutrient element residual rate,water holding capacity,water holding rate and water absorption rate of leaf and twig litters to nitrogen addition were explored.The results showed that:(1)With the continuation of decomposition time,carbon,nitrogen and phosphorus content of leaf and twig litters in two types of forests showed the trends of release,enrichment-release and enrichment,respectively,and the residue rates of C,N and P in leaf litters were significantly lower than those in twig litters(p<0.05).(2)The maximum water holding capacity and water absorption rate of leaf litters were significantly higher than that of twig litters(p<0.05).After 24 months of decomposition,compared with CK,the C residual rates of leaf and twig litters in two types of forests,and the N residual rate of leaf litters in P.armandii forest under LN treatment were reduced by 1.98%~7.27% and 10.79%,respectively.The C residual rates of leaf and twig litters in two types of forests,and the N residual rate of leaf and twig litters in P.armandii forest and twig litters in P.yunnanensis forest,the P residual rate of twig litters in P.armandii forest under HN treatment increased by 4.26%~9.08%,11.94%~44.51% and 42.42%,respectively.(3)After 24 months of decomposition,compared with CK,the maximum water holding capacity and water absorption rate of leaf and twig litters in P.armandii forest and leaf litters in P.yunnanensis forest under LN,MN and HN treatments decreased by 11.44%~25.24% and 5.81%~32.23%,respectively;while twig litters i

关 键 词：氮添加 凋落叶 凋落枝 养分残留 持水量 持水率 吸水速率 

分 类 号：S715[农业科学—林学]