氮沉降对缙云山柑橘林不同季节土壤微生物群落结构的影响

发布时间：2018-09-09 19:25

【摘要】：土壤微生物积极参与生态系统的物质循环和转化.人类活动造成全球氮沉降量激增,引起土壤微生物群落结构和功能的改变,进而导致生态系统失衡.2014年6月—2015年5月在缙云山柑橘林建立野外模拟氮沉降试验样地,原位设置4个施肥水平:对照(N0,0 g·m~(-2)·a~(-1))(以N计,下同)、低氮(N20,20 g·m~(-2)·a~(-1)),中氮(N4 0,40 g·m~(-2)·a~(-1))和高氮(N60,60 g·m~(-2)·a~(-1)).施氮处理2 d后,采用磷脂脂肪酸(PLFA)标记法和ACE(Automated Soil CO_2Exchange Station,UK)自动土壤呼吸监测系统对土壤微生物群落结构、土壤温湿度进行测定.研究表明:(1)不同季节土壤微生物对氮沉降的响应各异,春季氮沉降抑制土壤微生物量,夏、秋、冬季N40处理提高了土壤微生物量,N20、N60表现为抑制土壤微生物量;氮沉降对土壤温度有显著影响,但对土壤湿度影响不明显(p0.05).(2)土壤微生物丰富度指数和Shannon-Wiener多样性指数在中氮沉降条件下达最大;Pielou均匀度指数则表现不一致,春季和夏季在中氮浓度下最大,秋季在高氮处理下最大,冬季则在低氮处理下最大.(3)土壤温度与放线菌呈显著负相关(p0.01);土壤湿度与细菌和总PLFA呈显著正相关(p0.01),与放线菌呈显著正相关(p0.05).综合分析表明,土壤微生物受土壤温度和含水量的共同影响,氮沉降降低了土壤微生物含量,此研究结果支持了氮沉降抑制土壤微生物的认识.
[Abstract]:Soil microbes are actively involved in the material cycle and transformation of ecosystems. Human activities caused a rapid increase in the amount of global nitrogen deposition, resulting in changes in the structure and function of soil microbial communities, which led to ecosystem imbalances. From June 2014 to May 2015, a field simulated nitrogen deposition test plot was established in the citrus forest of Jinyun Mountain, Jinyun Mountain, from June 2014 to May 2015. Four fertilization levels were set in situ: control (N0 ~ 0 g m-2) a ~ (-1) (in N, low nitrogen (N20 ~ (20) g m-2) a ~ (-1), in N (40 g m-2) a ~ (-1) and high nitrogen (N6060 g m-2) a ~ (-1). After 2 days of nitrogen application, the soil microbial community structure and soil temperature and humidity were determined by (PLFA) labeling of phospholipid fatty acids and ACE (Automated Soil CO_2Exchange Station,UK automatic soil respiration monitoring system. The results showed that: (1) the responses of soil microorganisms to nitrogen deposition were different in different seasons. Nitrogen deposition inhibited soil microbial biomass in spring, and increased soil microbial biomass in summer, autumn and winter with N _ (20) N _ (60). Nitrogen deposition had a significant effect on soil temperature, but it had no significant effect on soil moisture (p0.05). (_ 2). Soil microbial richness index and Shannon-Wiener diversity index were not consistent under medium nitrogen deposition condition. In spring and summer, the maximum concentration of medium nitrogen was found in summer, and in autumn, it was the largest in high nitrogen treatment. In winter, soil temperature was significantly negatively correlated with actinomycetes (p0.01), soil moisture was positively correlated with bacteria and total PLFA (p0.01), and soil moisture was positively correlated with actinomycetes (p0.05). Comprehensive analysis shows that soil microbes are affected by soil temperature and water content together, nitrogen deposition reduces soil microbial content, which supports the understanding that nitrogen deposition inhibits soil microorganisms.
【作者单位】：西南大学资源环境学院三峡库区生态环境教育部重点实验室;重庆市涪陵区旅游局;重庆市涪陵区林业局;
【基金】：国家自然科学基金(No.41271291) 国家高技术研究发展计划(863)(No.2006AA10Z427)~~
【分类号】：S154.3;S666

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