摘要
自生固氮是陆地生态系统氮素的重要来源。本研究以位于西藏拉萨的肥料长期定位试验站为平台,选取不施肥(CK)、单施化肥(F)、单施羊粪(M)、化肥配施羊粪(FM)和化肥配施秸秆(FS)5个处理,于青稞收获期采集土样,采用^(15)N同位素标记、定量PCR和高通量测序技术,分析不同施肥模式下土壤理化性质、固氮微生物丰度、群落结构和潜在固氮速率的变化规律,以期为西藏高原青稞田制定科学合理的施肥策略,保障西藏高原农业绿色发展提供科学依据。结果表明:1)相比于CK和F处理,M、FM和FS处理可显著(P<0.05)提高土壤有机碳和全氮含量。FM处理下土壤铵态氮含量最高,且显著高于其他施肥处理(P<0.05),而M处理下土壤有机碳、全氮、硝态氮、有效磷和速效钾含量最高,且显著高于其他施肥处理(P<0.05)。2)不同施肥处理下青稞田土壤潜在固氮速率为2.63~4.07μg∙kg^(−1)∙d^(−1)。施肥会降低土壤潜在固氮速率,增施有机肥(羊粪或秸秆)则加剧了抑制效应,但羊粪的抑制效应小于秸秆,土壤铵态氮含量是影响土壤潜在固氮速率的主要因子。3)M或FM处理可显著(P<0.05)提高nifH基因丰度,而F或FS处理则相反,土壤全氮含量是影响nifH基因丰度的关键因子。4)不同施肥模式显著改变了固氮微生物群落结构,其群落结构相似性大致可以分为3类,分别为CK、M以及施用化肥处理(F、FM和FS),有效磷、pH和C/N是调控固氮微生物群落结构的关键因子。综上所述,单施羊粪(M)处理是提高青稞田土壤肥力、增加固氮微生物丰度,减少固氮速率下降幅度的最佳施肥模式。
Free-living nitrogen fixation(FLNF)by diazotrophs is an important nitrogen(N)source in terrestrial ecosystems and may reprensent a viable solution to environmental pollution caused by N over-fertilization.Studying the impact of different fertilizer regimes in highland barley fields on the diazotrophic community profiles and potential N fixation rates(PNFR)may provide scientific fertilization strategies and a theoretical basis for agricultural green development in the Tibetan Plateau.Here,quantitative PCR,highthroughput sequencing and ^(15)N labeling methods were used to better understand the impact of different fertilizer regimes on the abundance and composition of diazotrophs as well as the potential N fixation rates in highland barley fields on the Tibetan Plateau.The experiment included five treatments:a control without fertilizer(CK);N,phosphorus(P)and potassium(K)mineral fertilzers(F);manure fertilizer(M);mineral NPK fertilizers plus manure(FM);and mineral NPK fertilizer plus straw(FS).The results showed that:1)compared with the CK and F treatments,the M,FM and FS treatments significantly(P<0.05)increased the contents of soil organic carbon(C)and total N.Moreover,the ammonium nitrogen(NH^(+)_(4)-N)content was significantly(P<0.05)higher in the FM treatment than in the other treatments.The highest contents of organic C,total N,nitrate N(NO3−-N),available P and available K were observed in the M treatment,and their contents were significantly(P<0.05)higher than those in the other treatments.2)The PNFR ranged from 2.63 to 4.07μg∙kg^(−1)∙d^(−1) under different fertilizer treatments.Fertilization,especially the application of organic fertilizers(sheep manure or straw),reduced the PNFR,and the inhibitory effect of straw on PNFR was higher than that of sheep manure.The soil NH^(+)_(4)-N content was the main factor affecting PNFR.3)The M and FM treatments significantly(P<0.05)increased diazotrophic abundance,while the opposite was observed for the F and FS treatments.The total N content was the key factor
作者
马瑞萍
戴相林
刘国一
谢永春
高小丽
高雪
MA Ruiping;DAI Xianglin;LIU Guoyi;XIE Yongchun;GAO Xiaoli;GAO Xue(State Key Laboratory of Hulless Barley and Yak Germplasm Resources and Genetic Improvement,Lhasa 850000,China;Institute of Resources and Environment,Tibet Academy of Agricultural and Animal Husbandry Sciences,Lhasa 850000,China;Institute of Coastal Agriculture,Hebei Academy of Agriculture and Forestry Sciences,Tangshan 063299,China;Institute of Agriculture Research,Tibet Academy of Agricultural and Animal Husbandry Sciences,Lhasa 850000,China)
出处
《中国生态农业学报（中英文）》
CAS
CSCD
北大核心
2021年第10期1692-1703,共12页
Chinese Journal of Eco-Agriculture
基金
省部共建青稞和牦牛种质资源与遗传改良国家重点实验室自主课题(XZNKY-2020-C-007Z09)
西藏自治区自然科学基金项目(XZ2019ZRG-98)资助。
关键词
施肥模式
青稞农田
自生固氮
潜在固氮速率
西藏高原
Fertilizer pattern
Highland barley field
Free-living N fixation
Potential N fixation rate
Tibetan Plateau
