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大伙房水库流域水源涵养林植被类型对土壤NH4+-N和NO3--N淋溶的影响

  

  1. (1福建农林大学林学院, 福州 350002; 2辽宁老秃顶子国家级自然保护区抚顺管理局, 辽宁抚顺 113208; 3辽宁石油化工大学生态环境研究院, 辽宁抚顺 113001)
  • 出版日期:2017-08-10 发布日期:2017-08-10

Effects of vegetation type of water conservation forests on soil NH4+-N and NO3--N lea-ching in Dahuofang watershed.

HU Ya-lin1, LIU Jie2, FAN Zhi-ping3*, TU Zhi-hua3, LU Cong3, LIU Jian-zhi3#br#   

  1. (1College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China; 2 Fushun Authority of Liaoning Laotudingzi National Nature Reserve, Fushun 113208, Liaoning, China; 3Institute of Ecoenvironmental Sciences, Liaoning Shihua University, Fushun 113001, Liaoning, China).
  • Online:2017-08-10 Published:2017-08-10

摘要:

流域内植被类型是土壤氮素淋溶迁移的重要影响因子,降雨丰水季节不同植被类型土壤氮素淋溶是量化评价流域土壤氮素流失和水质变化的关键。本研究采用离子交换树脂袋法分析降雨丰水期槭树蒙古栎林、落叶松人工林和山杨林3种植被类型土壤NH4+-N和NO3--N淋溶季节动态特征。结果发现,降雨丰水期(7—9月)不同植被类型土壤无机氮含量(NH4+-N和NO3--N)动态变化差异显著(P<0.05),NH4+-N在无机N中占73.4%~93.3%,槭树-蒙古栎林、山杨林NO3--N含量7月份最大,而落叶松人工林NO3--N含量8月份最大;土壤氮素淋溶的主要成分是NO3--N,落叶松人工林土壤氮潜在性淋溶高于槭树-蒙古栎林和山杨林;土壤微生物生物量碳(MBC)和氮(MBN)随着土层加深逐渐减小,阔叶林MBC和MBN显著大于落叶松人工林;土壤N淋溶量与MBN呈显著负相关,证明土壤微生物N固持作用能减少N淋溶流失。据此结果,建议在该流域开展水源涵养林建设中应加强河岸带天然林保护和促进人工水源涵养林转变为天然次生林。
 

关键词: 森林景观, 空间点格局, 关联动态性, 空间格局动态

Abstract: Vegetation types play an important role in controlling soil nitrogen (N) leaching that is a key indicator of soil N loss and water eutrophication in a watershed. In this study, we measured soil NH4+-N and NO3--N leaching using ionexchange resin bags method in Acer mono-Quercus mongolica, Larix gmelinii and Populus davidiana water conservation forests in the Dahuofang watershed. Our results showed that soil NH4+-N and NO3--N concentrations were significantly different under different vegetations during the precipitation abundant season from July to September. Soil NH4+-N accounted for 73.40%-93.30% of soil total inorganic N. In July, soil NO3--N concentration was the highest in A. mono-Q. mongolica and P. davidiana forests, while soil NO3--N content in L. gmelinii plantation was the highest in August. NO3--N is the main form of soil N under leaching loss, and soil N loss was higher in L. gmelinii plantation compared to A. mono-Q. mongolica and P. davidiana forests. Soil microbial biomass carbon (MBC) and nitrogen (MBN) decreased gradually with increasing soil depth, and soil MBC and MBN was significantly higher in A. mono-Q. mongolica and P. davidiana forests than that in L. gmelinii plantation. There was a negative relationship between soil N loss and MBN, suggesting a reduced soil N leaching loss by soil microbial retention. Our results implied that more attention should be paid to the protection of natural secondary forests and the promotion of the artificial water conservation plantations into natural secondary forests in the Dahuofang watershed in order to reduce soil N loss.

Key words: association dynamic, forest landscape, spatial pattern dynamic, spatial point pattern