Variations in the nitrogen saturation threshold of soil respiration in grassland ecosystems

NWIPB OpenIR

	Variations in the nitrogen saturation threshold of soil respiration in grassland ecosystems
	Wang, Chao; Ren, Fei; Zhou, Xuhui; Ma, Wenhong; Liang, Cunzhu; Wang, Jinzhou; Cheng, Jianwei; Zhou, Huakun; He, Jin-Sheng
	2020
发表期刊	BIOGEOCHEMISTRY
卷号	148 期号:3
摘要	Over the last century, anthropogenic activities have increased nitrogen (N) deposition considerably, which significantly affects ecosystem processes and has the potential to induce N saturation in the future. The continuous increase in N deposition may cause a non-linear response in soil respiration (Rs), an important component of carbon (C) cycling. However, little is known about N saturation threshold of soil respiration. In this study, we conducted coordinated experiments in four grassland types across northern China with four N addition levels to explore patterns in the Rs saturation threshold. Our results showed that an Rs saturation threshold generally exists in grassland ecosystems in response to N addition gradients. The N saturation threshold of Rs occurred at an average rate of 50 kg N ha(-1) yr(-1), but varied widely with grassland type; the N saturation threshold occurred at rates of 100, 50, 50, and 25 kg N ha(-1) yr(-1) in the alpine meadow, meadow steppe, typical steppe, and desert steppe, respectively. Autotrophic respiration (Ra) and heterotrophic respiration (Rh) responded to N addition gradients differently. Ra increased initially and became saturated at a rate of 50 kg N ha(-1) yr(-1) and declined thereafter. In contrast, Rh decreased monotonically after N addition. Structural equation models further confirmed that the effects of N addition gradients on Rs were primarily determined by the non-linear response of belowground biomass. Interestingly, the compiled global dataset showed that the N saturation threshold of Rs increased with precipitation and soil moisture. These findings indicate that the stimulating effect of N deposition on Rs and Ra might diminish with increasing N deposition in the future, especially in dry grassland ecosystems.
关键词	Carbon cycling Nitrogen deposition Coordinated experiments Threshold Precipitation
文献类型	期刊论文
条目标识符	http://210.75.249.4/handle/363003/60359
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	Wang, Chao,Ren, Fei,Zhou, Xuhui,et al. Variations in the nitrogen saturation threshold of soil respiration in grassland ecosystems[J]. BIOGEOCHEMISTRY,2020,148(3).
APA	Wang, Chao.,Ren, Fei.,Zhou, Xuhui.,Ma, Wenhong.,Liang, Cunzhu.,...&He, Jin-Sheng.(2020).Variations in the nitrogen saturation threshold of soil respiration in grassland ecosystems.BIOGEOCHEMISTRY,148(3).
MLA	Wang, Chao,et al."Variations in the nitrogen saturation threshold of soil respiration in grassland ecosystems".BIOGEOCHEMISTRY 148.3(2020).