不同林龄杨树人工林土壤有效氮对模拟氮沉降的初期响应

发布时间：2018-07-10 06:22

本文选题：氮沉降 + 杨树人工林　；参考：《南京林业大学学报(自然科学版)》2016年01期

【摘要】：为了解森林生态系统对持续氮增长和快速氮循环的响应模式及反馈机制,选择3种林龄杨树人工林作为试验样地,设置N_0(0 g/(m~2·a))、N_1(5 g/(m~2·a))、N_2(10 g/(m~2·a))、N_3(15 g/(m~2·a))、N_4(30 g/(m~2·a))共5个不同浓度进行模拟氮沉降实验,探讨3种林龄杨树人工林土壤有效氮含量及对模拟氮沉降的响应。结果表明:1幼龄林、中龄林和过熟林的铵态氮占总有效氮含量的比例分别为1850%~2881%、2314%~3452%和32.60%~49.92%;2随着外源氮浓度的不断增加,3种林龄土壤硝态氮含量都呈显著的增加趋势,且高氮处理对有效氮的影响高于低氮处理,而铵态氮只在幼龄林和中龄林中高氮处理(N_3和N_4)之间差异显著;3幼龄林土壤硝态氮含量对不同浓度的氮沉降响应比中龄林和过熟林更为敏感,而铵态氮在3种林龄之间无显著规律;43种林龄土壤表层(0~10 cm)的铵态氮、硝态氮含量对氮沉降响应更加敏感。
[Abstract]:In order to understand the response model and feedback mechanism of forest ecosystem to sustained nitrogen growth and rapid nitrogen cycling, three forest age poplar plantations were selected as experimental plots, and N0 (0 g / (m ~ 2 a) / (m ~ (2) a) / N ~ (1) (5 g / (m ~ (2) a) ~ (2) N _ 2 (10 g / (m ~ 2 a) N _ (3) (15 g / (m ~ (2) a) N _ 4 (30 g / (m ~ 2 a) were used to simulate nitrogen deposition experiments. To study the soil available nitrogen content and its response to simulated nitrogen deposition in three forest age poplar plantations. The results showed that the ratio of ammonium nitrogen to total available nitrogen in young forest, middle age forest and overmature forest was 1850 ~ 2881 ~ 2314 ~ 3452% and 32.60% ~ 49.92 ~ 2 ~ 2 respectively. The nitrate content of three kinds of forest age soil showed a significant increasing trend with the increasing of exogenous nitrogen concentration. The effect of high nitrogen treatment on available nitrogen was higher than that of low nitrogen treatment. However, there was significant difference in ammonium nitrogen content between young and middle aged forest (N _ 3 and N _ 4). Soil nitrate content in young forest was more sensitive to different concentrations of nitrogen deposition than that of middle and overmature forest. However, there was no significant regularity of ammonium nitrogen among three forest ages. There were 43 species of ammonium nitrogen in the topsoil (0 ~ 10 cm) of forest age, and nitrate content was more sensitive to nitrogen deposition.
【作者单位】：南京林业大学南方现代林业协同创新中心江苏省林业生态工程重点实验室南京林业大学生物与环境学院;江苏省东台市林场;
【基金】：国家自然科学基金项目(31270489) 国家重点基础研究发展计划(2012CB416904) 江苏高校优势学科建设工程资助项目(PAPD)
【分类号】：S714

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