模拟氮沉降对华西雨屏区天然常绿阔叶林凋落叶分解过程中K、Ca、Mg元素释放的影响  

Effects of Simulated Nitrogen Deposition on the Releases of Potassium,Calcium,and Magnesium During Litter Decomposition in a Natural Evergreen Broadleaved Forest in the Rainy Area of Western China

作　　者：胡峻嶍 陈蕙心 周世兴[1] 向元彬[1] 黄从德[1] HU Jun-xi;CHEN Hui-xin;ZHOU Shi-xing;XIANG Yuan-bin;HUANG Cong-de(College of Forestry,Sichuan Agricultural University,Chengdu 611130,Sichuan,China)

机构地区：[1]四川农业大学林学院,四川成都611130

出　　处：《林业科学研究》2020年第3期124-131,共8页Forest Research

基　　金：国家“十二五”科技支撑计划项目(2010BACO1A11)。

摘　　要：[目的]研究氮沉降背景下凋落叶分解过程中钾(K)、钙(Ca)、镁(Mg)元素的释放动态,揭示森林生态系统在氮沉降持续增加背景下养分元素的循环过程。[方法]在华西雨屏区天然常绿阔叶林中设置对照(CK)、低氮(L)、中氮(M)和高氮沉降(H)4个处理,以NH4NO3为氮源,采用尼龙网袋法对凋落叶进行模拟氮沉降分解试验,研究了凋落叶分解过程中K、Ca、Mg元素浓度及残留率,探讨氮沉降对凋落叶分解过程中养分释放的影响。[结果]经过1年的分解,模拟氮沉降显著抑制了凋落叶分解过程中K元素浓度的下降,显著促进了Ca元素浓度的下降,对Mg元素浓度无显著影响。在各处理中,K元素呈净释放模式,Ca元素表现为释放-富集的交替模式,Mg元素呈富集-释放模式,模拟氮沉降未改变凋落叶分解中K、Ca、Mg元素的释放模式。分解1年后,L、M和H处理的K元素残留率分别比CK高3.91%、10.27%和13.91%,模拟氮沉降显著抑制了凋落叶分解过程中K元素的释放;L、M和H处理的Ca元素残留率分别比CK低6.39%、6.51%和15.93%,模拟氮沉降显著促进了凋落叶分解过程中Ca元素的释放;L、M和H处理的Mg元素残留率与CK差异不显著,模拟氮沉降对凋落叶分解过程中Mg元素的释放无显著影响。[结论]模拟氮沉降未改变凋落叶分解过程中K、Ca、Mg元素的释放模式,但对凋落叶分解过程中K、Ca、Mg元素的释放速率产生了不同的影响。[Objective]To study the release dynamics of potassium,calcium,and magnesium during litter decomposition under simulated nitrogen deposition,so as to better understand the nutrient cycling process of forest ecosystem under continuously increasing nitrogen depositions.[Method]NH4NO3 was used to establish the low level(L),medium level(M),high(H)level and the control(CK)treatments of nitrogen deposition in a natural evergreen broadleaved forest in the Rainy Area of Western China.Nylon mesh bag method was employed to simulate litter decomposition under nitrogen deposition.Experiment continued for one year and the concentration,remaining percentages and release patterns of potassium,calcium,and magnesium during litter decomposition were studied.[Result]After one year of decomposition,the simulated nitrogen deposition significantly inhibited the decrease of potassium in the process of litter decomposition,which significantly promoted the decrease of calcium concentration and had no significant effects on magnesium concentration.However,the simulated nitrogen deposition did not change the release pattern of potassium,calcium,and magnesium during litter decomposition.The potassium exhibited a net release pattern in all the four treatments,the calcium exhibited release-enrichment alternate pattern and the magnesium exhibited an enrichment-release pattern.The remaining percentages of potassium in L,M and H treatments increased by 3.91%,10.27%and 13.91%respectively compared with the CK,showing that the nitrogen deposition significantly inhibited the release of potassium.The remaining percentage of calcium in L,M and H treatments decreased by 6.39%,6.51%and 15.93%respectively compared with CK,i.e.nitrogen deposition significantly promoted the release of calcium.There was no significant difference in the remaining percentages of magnesium between the control and the nitrogen treatments i.e.simulated nitrogen deposition had no significant effect on the dynamics of magnesium during litter decomposition.[Conclusion]Simulated nitr

关 键 词：凋落叶分解 K、Ca、Mg元素 养分释放 氮沉降 天然常绿阔叶林 华西雨屏区 

分 类 号：S718.5[农业科学—林学]