2024年7月23日 星期二
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
2021年 第30卷 第6期 页码[10-18]    下载全文[8.7MB]  
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。

Abstract

 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. pseudoacacia plantations with relatively low stand ages are higher, while the negative feedback of C and P release of litter from plantations with relatively high stand ages to nitrogen deposition influence is more evident.

关键词刺槐林地; 林龄; 凋落物; 氮沉降; 化学特性; 凋落物分解
Key wordsRobinia pseudoacacia Linn. plantation; stand age; litter; nitrogen deposition; chemical characteristics; litter decomposition
作者张晓曦1, 胡嘉伟1, 王丽洁1, 米皓皓1, 回虹燕1, 李利平2
所在单位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
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基金项目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)