Organic nitrogen addition causes decoupling of microbial nitrogen cycles by stimulating gross nitrogen transformation in a temperate forest soil

NWIPB OpenIR

	Organic nitrogen addition causes decoupling of microbial nitrogen cycles by stimulating gross nitrogen transformation in a temperate forest soil
	Lu, Mingzhu; Cheng, Shulan; Fang, Huajun; Xu, Meng; Yang, Yan; Li, Yuna; Zhang, Jinbo; Mueller, Christoph
	2021
发表期刊	GEODERMA
卷号	385
摘要	External inorganic and organic nitrogen (N) inputs can contrastingly affect the transformation and availability of N in forest soils. Studies have mainly focused on the effects of inorganic N enrichment, whereas little is known about the effects of organic N input on soil gross N transformation and the underlying microbial mechanisms. Here we conducted a laboratory N-15 tracing study in a temperate needle-broadleaved mixed forest with a fertilization rate of 0, 20, 60, and 120 kg urea-N ha(-1) yr(-1) over three years. We investigated the key drivers of soil N transformation processes using a 15 N tracing model in the context of selected soil chemical properties and microbial characteristics. Urea addition did not change soil gross N mineralization rates, while stimulating mineralization of labile organic N (M-Nlab). Urea addition at a rate of 120 kg N ha(-1) yr(-1) significantly increased autotrophic nitrification and gross nitrification rates by 88% and 96%, respectively. In contrast, all the three levels of urea addition significantly reduced gross microbial N immobilization by 28% to 52%, leading to an increase in the accumulation of soil NO3--N in the top 10 cm soil layer by 38% to 88%. The changes in autotrophic nitrification were primarily driven by acid-tolerant ammonia-oxidizing archaea (AOA). Fungi were responsible for the change in heterotrophic nitrification under organic N enrichment. Gross N transformation rates were predominately regulated by AOA and fungal abundances as well as soil NO3--N content under high level of organic N addition. The response of soil N transformation to exogenous organic N input depended on N addition level with the threshold rate being estimated to be 60-120 kg N ha(-1) yr(-1) . All lines of evidence showed that the temperate needle-broadleaved mixed forest is moving towards an opener microbial N cycle under elevated organic N deposition. Our finding suggests that the effect of organic N input on soil gross N transformation is different from that of inorganic N input, which should be considered in ecosystem process models.
关键词	Organic N deposition Gross N transformations N-15 tracing model Microbial group abundances Temperate needle-broadleaved mixed forest
文献类型	期刊论文
条目标识符	http://210.75.249.4/handle/363003/60843
专题	中国科学院西北高原生物研究所
推荐引用方式 GB/T 7714	Lu, Mingzhu,Cheng, Shulan,Fang, Huajun,et al. Organic nitrogen addition causes decoupling of microbial nitrogen cycles by stimulating gross nitrogen transformation in a temperate forest soil[J]. GEODERMA,2021,385.
APA	Lu, Mingzhu.,Cheng, Shulan.,Fang, Huajun.,Xu, Meng.,Yang, Yan.,...&Mueller, Christoph.(2021).Organic nitrogen addition causes decoupling of microbial nitrogen cycles by stimulating gross nitrogen transformation in a temperate forest soil.GEODERMA,385.
MLA	Lu, Mingzhu,et al."Organic nitrogen addition causes decoupling of microbial nitrogen cycles by stimulating gross nitrogen transformation in a temperate forest soil".GEODERMA 385(2021).