主办单位:中国气象局沈阳大气环境研究所
国际刊号:ISSN 1673-503X
国内刊号:CN 21-1531/P

气象与环境学报 ›› 2013, Vol. 29 ›› Issue (4): 106-112.doi:

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冻融交替对河岸缓冲带土壤无机氮和土壤微生物量氮的影响

范志平1,2 李胜男1,2,3 李法云1 高洪翠1,2,3 闫加亮2   

  1. 1.辽宁石油化工大学生态环境研究院,辽宁 抚顺 113001;2.中国科学院沈阳应用生态研究所,辽宁 沈阳 110016;3.中国科学院研究生院,北京 100049
  • 出版日期:2013-08-31 发布日期:2013-08-31

Effect of freezing-thawing on soil dissolved inorganic nitrogen and soil microbial biomass nitrogen in riparian zone

FAN Zhi-ping1,2 LI Sheng-nan1,2,3 LI Fa-yun2 GAO Hong-cui1,2,3 YAN Jia-Liang2
  

  1. 1. Institute of Eco-environment Sciences, Liaoning Shihua University, Fushun 113001, China; 2. Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; 3. Graduate University of Chinese Academy of Sciences, Beijing 100049, China
  • Online:2013-08-31 Published:2013-08-31

摘要: 全球气候变化引起的中高纬度地区积雪覆盖和降雪格局变化,造成该区域土壤冻融交替强度和频次变化,是土壤氮循环的重要影响因素。冻融温差和冻融循环次数影响微生物数量和群落的变化,进而影响土壤氮素生物地球化学循环。以大伙房水库实验林场小流域的河岸缓冲带生态系统为研究对象,通过分析冻融交替对河岸缓冲带土壤无机氮和土壤微生物量氮的影响,阐明冻融交替对土壤无机氮含量变化的影响机制,为评估小流域氮素流失风险提供依据。结果表明:随着冻融循环次数的增加,土壤无机氮含量呈增加趋势;不同温差的冻融循环处理对土壤无机氮影响不同,冻融条件为-5/+5℃和-20/+5℃时土壤无机氮含量在冻融循环10次之后分别为34.9±0.9 mg/kg和37.2±0.8 mg/kg,是处理前的1.21和1.41倍;冻融温差和冻融循环次数对土壤NH4+–N含量有极显著影响(P<0.01),土壤冻融10次后土壤NH4+–N含量是对照处理的4—10倍;冻融循环次数对土壤NO3–N含量有显著影响(P<0.05),冻融温差对NO3–N含量无显著影响(P>0.05);土壤微生物量氮含量对冻融循环的响应显著(P<0.01)。可见,冻融交替显著增加了土壤无机氮含量,由于早春季节植被对无机氮吸收较少,可能增大土壤氮素随冰雪融化的淋溶流失风险。

关键词: 冻融交替, 无机氮, 土壤微生物量氮, 河岸缓冲带, 小流域

Abstract: Global climate change makes snow pattern of terrestrial ecosystems change in the middle and high latitude areas, which is critical to soil nitrogen cycling, and it can lead to changes of intensity and frequency of soil freezing-thawing cycles. The freezing-thawing cycles could affect soil nitrogen cycles through microbial biomass and community. The study was carried out in Dahuofang experimental forest watershed. The effect mechanism of freezing-thawing cycles on inorganic nitrogen content of soil was revealed, which could provide the references for assessing the risk of N loss in the riparian ecosystem. The results show that soil inorganic nitrogen content is in an increasing trend with the increasing times of freezing-thawing cycles. Different freezing temperature has the significant effect on inorganic nitrogen. The inorganic nitrogen contents are 34.9±0.9 mg/kg and 37.2±0.8 mg/kg after 10 freezing-thawing cycles with the -5℃/+5℃ and -20℃/+5℃ treatments, which are 1.21 and 1.41 times of initial inorganic nitrogen content of soil samples, respectively. Furthermore, freezing-thawing cycles and its temperature difference have the significant effect on soil NH4 +-N content (P<0.01). After 10 freezing-thawing cycles, soil NH4 +-N content is 4-10 times of soil samples for +5 ℃ treatment. Freezing-thawing cycles have the significant influences on soil NO3- -N content (P< 0.05), while its temperature difference has not the significant influences on NO3-N content (P>0.05). The response of soil microbial biomass nitrogen content to freezing-thawing cycles is significant (P<0.01). Thus, freezing-thawing changes increase the inorganic nitrogen content of soil. Because of less absorption of inorganic nitrogen by vegetation in early spring, the risk of soil nitrogen loss may increase with snow melting in study area.

Key words: Freezing-thawing change, Inorganic nitrogen, Microbial biomass nitrogen of soil, Riparian zone, Small watershed