不同林龄刺槐林地凋落物分解及养分释放对氮沉降的响应差异  

Response differences in decomposition and nutrient release of litter from Robinia pseudoacacia plantations with different stand ages to nitrogen deposition

作　　者：张晓曦 胡嘉伟 王丽洁 米皓皓 回虹燕 李利平 ZHANG Xiaoxi;HU Jiawei;WANG Lijie;MI Haohao;HUI Hongyan;LI Liping(College of Life Sciences, Yan’an University, Yan’an 716000, China;Chengnan College, Changsha University of Science and Technology, Changsha 410076, China)

机构地区：[1]延安大学生命科学学院,陕西延安716000 [2]长沙理工大学城南学院,湖南长沙410076

出　　处：《植物资源与环境学报》2021年第6期10-18,共9页Journal of Plant Resources and Environment

基　　金：国家自然科学基金资助项目(31800370);延安大学科研计划资助项目(YDY2020-34);国家大学生创新创业训练计划项目(S202010719013);延安大学大学生创新创业训练计划项目(D2020096)。

摘　　要：以林龄10、20、33和43 a刺槐(Robinia pseudoacacia Linn.)林地的凋落物为研究对象,分别在无氮沉降和12 g·m^(-2)·a^(-1)氮沉降处理下进行150 d的室内模拟分解试验,测定不同林龄林地凋落物的分解和C、N、P释放对氮沉降的响应差异。结果表明:随林龄增加,刺槐林地凋落物的C、N和P含量总体呈增加趋势,而木质素、多酚和缩合单宁含量以及化学丰富度和化学分异性总体呈降低趋势,C/N比、C/P比和木质素/N比在林龄43 a林地凋落物中最低。表明随林龄增加,林地凋落物的基质质量总体呈优化趋势,而其化学丰富度和分异性则呈降低趋势。氮沉降显著(P<0.05)或极显著(P<0.01)抑制林龄10~33 a林龄林地凋落物的全程分解,对林龄43 a林地凋落物的分解无显著影响;并在分解试验中后期抑制林龄33和43 a林地凋落物的C释放、林龄20 a林地凋落物的N释放和林龄43 a林地凋落物的P释放。三因素重复测量方差分析结果表明:分解时间和氮沉降水平以及两者的交互作用、氮沉降水平和林龄的交互作用均对凋落物的C、N和P释放具有显著或极显著影响,三者的交互作用仅对凋落物的N和P释放具有极显著影响。总体而言,在12 g·m^(-2)·a^(-1)氮沉降处理下,较低林龄刺槐林地凋落物分解受抑制程度更高,而较高林龄林地凋落物的C和P释放对氮沉降影响的负反馈更明显。Taking litter from Robinia pseudoacacia Linn.plantations with the stand ages of 10,20,33 and 43 a as research objects,an indoor simulated decomposition experiment was conducted under treatments without nitrogen deposition or with 12 g·m^(-2)·a^(-1) nitrogen deposition for 150 d,and the response differences in decomposition and C,N and P release of litter from plantations with different stand ages to nitrogen deposition were assayed.The results show that with the increase of stand age,C,N and P contents of litter from R.pseudoacacia plantation show a tendency to increase in general,while contents of lignin,polyphenol and condensed tannin,and chemical richness and chemical dispersion show a tendency to decrease in general,and C/N ratio,C/P ratio and lignin/N ratio of litter from plantation with stand age of 43 a are the lowest.It is indicated that with the increase of stand age,the substrate quality of litter from plantation shows an optimization trend in general,while its chemical richness and dispersion show a trend of decrease.Nitrogen deposition significantly(P<0.05)or extremely significantly(P<0.01)inhibits the entire decomposition process of litter from plantations with stand age of 10-33 a,but has no significant effect on the decomposition of litter from plantation with stand age of 43 a;it also inhibits C release of litter from plantations with stand age of 33 and 43 a in the middle and later stages,N release of litter from plantation with stand age of 20 a and P release of litter from plantation with stand age of 43 a.The result of three-way repeat-measured ANOVA shows that decomposition time,nitrogen deposition level and their interaction,interaction of nitrogen deposition level and stand age have significant or extremely significant effects on C,N and P release of litter,and the interaction of the three only has a extremely significant effect on N and P release of litter.Overall,under treatment with 12 g·m^(-2)·a^(-1) nitrogen deposition,the inhibitory degree on decomposition of litter from R.pseudoa

关 键 词：刺槐林地 林龄 凋落物 氮沉降 化学特性 凋落物分解 

分 类 号：Q949.751.9[生物学—植物学] S718.5[农业科学—林学]