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草业学报 ›› 2014, Vol. 23 ›› Issue (5): 49-60.DOI: 10.11686/cyxb20140506

• 论文 • 上一篇    下一篇

氮素添加对贝加尔针茅草原凋落物分解的影响

于雯超1,2,3,宋晓龙2,3,修伟明2,3,张贵龙2,3,赵建宁2,3,杨殿林1,2,3*   

  1. 1.沈阳农业大学园艺学院,辽宁 沈阳 110866;
    2.农业部环境保护科研监测所,天津 300191;
    3.农业部产地环境质量重点实验室,天津 300191
  • 收稿日期:2013-09-04 出版日期:2014-10-20 发布日期:2014-10-20
  • 通讯作者: Email:yangdianlin@caas.cn
  • 作者简介:于雯超(1988-),女,辽宁大连人,在读硕士。E-mail:leisituzi@163.com
  • 基金资助:

    国家自然科学基金项目(31170435),“十二五”国家科技计划项目(2012BAD13B07),中央级公益性科研院所基本科研业务费专项资金(农业部环境保护科研监测所)和农业部产地环境质量重点实验室/天津市农业环境与农产品安全重点实验室开放基金项目资助

Effects of additional nitrogen on litter decomposition in Stipa baicalensis grassland

YU Wen-chao1,2,3,SONG Xiao-long2,3,XIU Wei-ming2,3,ZHANG Gui-long2,3,ZHAO Jian-ning2,3,YANG Dian-lin1,2,3   

  1. 1.Department of Horticulture, Shenyang Agricultural University, Shenyang 110866, China;
    2.Agro-Environmental Protection Institute, Ministry of Agriculture, Tianjin 300191,China;
    3.Key Laboratory of Original Agro-environment Quality of Ministry of Agriculture and Tianjin Key Laboratory of Agro-environment and Safe-product, Tianjin 300191, China
  • Received:2013-09-04 Online:2014-10-20 Published:2014-10-20

摘要:

对内蒙古贝加尔针茅草原群落开展氮素添加实验,设置6个氮素添加水平,氮素类型为硝酸铵(NH4NO3):对照(N0),1.5 g N/m2(N15)、3.0 g N/m2(N30)、5.0 g N/m2(N50)、10.0 g N/m2(N100)和15.0 g N/m2(N150)。利用凋落物网袋分解法,研究贝加尔针茅、羊草和冷蒿3种植物不同器官凋落物分解对氮素添加的响应。结果表明:1) 3种植物不同器官凋落物C残留率的季节变化与植物残留率的变化趋势相同,呈释放模式。2)贝加尔针茅各器官凋落物分解95%所需时间为3.79~5.75年。羊草各器官凋落物分解95%所需时间为3.12~6.34年。冷蒿各器官凋落物分解95%所需时间为2.69~6.82年。3)不同植物、不同器官凋落物分解速率对氮素添加响应不同,初始化学组成不是控制凋落物分解的主要影响因子。4)凋落物分解速率与土壤铵态氮、硝态氮和土壤含水量无显著相关性,冷蒿凋落物与土壤微生物量碳氮显著相关。5)本试验进行期间,氮素添加对各器官凋落物分解无一致影响,仅个别施氮水平对不同器官凋落物分解速率及养分释放有促进或抑制作用。在氮素添加背景下,凋落物分解受到时间、分解底物类型及氮素输入水平的共同影响。

Abstract:

In grassland sites dominated by Stipa baicalensis grassland, we imposed six nitrogen levels: N0, N15, N30, N50, N100 and N150, respectively. At the various levels of nitrogen deposition, we placed litterbag with leaf, stalk and root litter of S. baicalensis (Sb), Leymus chinensis (Lc), Artemisia frigida (Af) on the experiment plots. Plots were sprayed NH4NO3 in the middle of June and July. The dynamics of C and N during litter decomposition were different. Different decomposition and nitrogen exchange patterns were observed among the three dominant plants studied. The current paradigm suggests close relationships between decomposition rates, C and N content and , C/N ratio. The results contrasted with that. Decomposition time for 95% degradation of litter was 3.79-5.75 years for Sb, 3.12-6.34 years for Lc, and 2.69-6.82 years for Af. The initial nutrient element concentration of litter determined the nutrient release pattern and the amount of the final net element release ratio. Through correlation analysis of litter decomposition and soil physical and chemical properties, we found: litter decomposition to be weakly correlated with NH4--N , NO3--N and soil moisture content. The carbon and nitrogen content of soil microbial biomass was significantly correlated with litter decomposition rate of Af. Thus, microorganisms are the key factor controlling litter decomposition rate of Af. Therefore, in the short term, nitrogen deposition had no significant effect on litter decomposition, only individual level of nitrogen promoting or inhibiting effect on different litter decomposition rate and nutrient releasing. It implied that the effects of N addition on litter decomposition depended on time, organs, and also N addition levels.

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