引用本文:邓玉峰,田善义,成艳红,胡正锟,刘满强,胡 锋,陈小云.模拟氮沉降下施石灰对休耕红壤优势植物根际土壤微生物群落的影响[J].土壤学报,2019,56(6):1449-1458.
DENG Yufeng,TIAN Shanyi,CHENG Yanhong,HU Zhengkun,LIU Manqiang,HU Feng,CHEN Xiaoyun.Effects of Liming on Rhizosphere Soil Microbial Communities of Dominant Plants in Fallowed Red Soil under Simulated Nitrogen Deposition[J].Acta Pedologica Sinica,2019,56(6):1449-1458
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模拟氮沉降下施石灰对休耕红壤优势植物根际土壤微生物群落的影响
邓玉峰1, 田善义1, 成艳红2, 胡正锟1, 刘满强1, 胡 锋1, 陈小云1
1.南京农业大学资源与环境科学学院;2.江西省红壤研究所
摘要:
氮沉降引起红壤酸化加剧和土壤生态系统功能退化。采用休耕植物自然演替恢复土壤生物多样性和生态系统功能;同时,针对氮沉降造成的土壤酸化,通过施石灰来调控土壤pH,以期加速土壤生态恢复进程。土壤微生物群落结构的改变能够指示土壤恢复措施的影响。为探究氮沉降背景下,石灰施用措施对休耕红壤生态功能的恢复效果,以高强度农作休耕地上最初出现的优势植物狗尾草(Setaria viridis (L.) Beauv)根际为研究对象,研究模拟氮沉降(0 kg•hm-2,45 kg•hm-2和90 kg•hm-2)下施石灰(0 kg•hm-2和110 kg•hm-2)对根际土壤微生物群落的影响。结果表明,模拟氮沉降降低了各类群微生物磷脂脂肪酸(PLFA)量、革兰氏阴/阳性细菌比及香农多样性指数。在没有额外施氮的处理中,施石灰降低了各类群微生物PLFA量。而氮和石灰交互作用下,各类群微生物PLFA量均随氮沉降量增加而增加。结构方程模型显示,石灰对微生物群落的影响最为强烈;模拟氮沉降和施石灰通过综合影响土壤pH、养分有效性及植物—微生物养分竞争而改变微生物群落结构和多样性。总之,模拟氮沉降下施用石灰措施能够改善休耕红壤生境,降低因氮沉降造成的酸化对根际微生物群落的危害,加速土壤生态系统恢复。
关键词:  退化红壤  休耕地  模拟氮沉降  生态恢复  根际土壤微生物
DOI:10.11766/trxb201808260218
分类号:
基金项目:国家自然科学基金项目(41371263)及中央业务费重点项目(KYTZ201404)
Effects of Liming on Rhizosphere Soil Microbial Communities of Dominant Plants in Fallowed Red Soil under Simulated Nitrogen Deposition
DENG Yufeng1, TIAN Shanyi1, CHENG Yanhong2, HU Zhengkun1, LIU Manqiang1, HU Feng1, CHEN Xiaoyun1
1.College of Resources and Environmental Sciences, Nanjing Agricultural University;2.Jiangxi Institute of Red Soil
Abstract:
【Objective】Unreasonable anthropogenic activities tend to cause gradual increase in global atmospheric nitrogen deposition, which has become one of the most important environmental problems that arouses attentions the world over. Red soil, as an important soil resource in China, has come to face a series of serious ecological problems, such as soil acidification, biological degradation and so on, owing to its own development characteristics and specific climate factors. At the same time, nitrogen deposition is liable to exacerbate soil acidification and degenerate functions of the red soil ecosystem, posing a serious threat to the red soil ecosystem and impeding sustainable development of the economy and society of the red soil region. In order to promote restoration and sustainable development of the ecological functions of red soil, a series of practices have been adopted, such as leave farmlands in fallow or “grain for green” and stop artificial interference of the soil to let the vegetation and then the soil recover in biodiversity and ecosystem function through natural succession. This study was oriented to explore the effects of atmospheric N deposition on the soil microbial community in the rhizosphere ofSetaria viridis (L.) Beauv Beauv, the dominant plants in fallow farmlands in the initial phase of the succession, as affected by soil acidification, controlled by liming. The factors of global change and comprehensive impact of artificial management practices were also taken into account.【Method】For the study, a field experiment designed to have three levels of artificial atmospheric N deposition, through N application, i.e., 0 kg•hm-2,45 kg•hm-2 and 90 kg•hm-2 and two levels of liming, i.e., 0 kg•hm-2 and 110 kg•hm-2. Samples of rhizospheric soil under Setaria viridis (L.) Beauv were collected and analyzed for the structure of the soil microbial community.【Result】Results showed that the simulated nitrogen deposition significantly inhibited the soil microbial community in rhizosphere by reducing its microbial phospholipid fatty acid (PLFA) content, the ratio of gram-negative bacteria/gram-positive ones, fungi / bacteria ratio, and Shannon diversity. In the plots without nitrogen deposition (0 kg•hm-2), liming decreased microbial PLFA, but significantly increased the ratio of Gram-negative bacteria to Gram-positive ones. The interaction of nitrogen and lime restrained the adverse effects of applying nitrogen and lime separately alone on microbial biomass. PLFA in all groups of soil microbes increased with decreasing nitrogen deposition. The structural equation model (SEM) shows that the effect of liming was much stronger on the microbial community. Simulated nitrogen deposition and liming jointly through interaction affected soil pH, nutrient availability and competition for nutrient between soil microbes and plants, thus altering structure and diversity of the soil microbial community.【Conclusion】This study demonstrates that the interaction of nitrogen and lime could improve rhizosphere soil environment, mitigate soil acidification, increase soil productivity, promote microbial growth and maintain stability of the microbial community structure and diversity in fallow red soil. In conclusion, application of lime can offset the adverse impacts of atmospheric nitrogen deposition on soil microbial community by improving the habitat of fallow red soil, alleviating damage to the soil microbial community in rhizosphere and promoting restoration of the soil ecosystem.
Key words:  Degraded red soils  Fallowed farmland  Simulated nitrogen deposition  Ecological restoration  Rhizosphere soil microorganism