Long-term antagonistic effect of increased precipitation and nitrogen addition on soil respiration in a semiarid steppe

Abstract

Changes in water and nitrogen (N) availability due to climate change and atmospheric N deposition could have significant effects on soil respiration, a major pathway of carbon (C) loss from terrestrial ecosystems. A manipulative experiment simulating increased precipitation and atmospheric N deposition has been conducted for 9 years (2005–2013) in a semiarid grassland in Mongolian Plateau, China. Increased precipitation and N addition interactively affect soil respiration through the 9 years. The interactions demonstrated that N addition weakened the precipitation‐induced stimulation of soil respiration, whereas increased precipitation exacerbated the negative impacts of N addition. The main effects of increased precipitation and N addition treatment on soil respiration were 15.8% stimulated and 14.2% suppressed, respectively. Moreover, a declining pattern and 2‐year oscillation were observed for soil respiration response to N addition under increased precipitation. The dependence of soil respiration upon gross primary productivity and soil moisture, but not soil temperature, suggests that resources C substrate supply and water availability are more important than temperature in regulating interannual variations of soil C release in semiarid grassland ecosystems. The findings indicate that atmospheric N deposition may have the potential to mitigate soil C loss induced by increased precipitation, and highlight that long‐term and multi‐factor global change studies are critical for predicting the general patterns of terrestrial C cycling in response to global change in the future.

Increased precipitation and nitrogen addition accelerate the temporal increase in soil respiration during 8‐year old‐field grassland succession

“…Increased soil respiration under the 8‐year N addition in this old‐field system agrees with the results of numerous previous studies in grasslands (Feng et al, 2017; Jia et al, 2012; Zhang et al, 2014; Zhou et al, 2014), but differs with those in forests (Janssens et al, 2010), semiarid grasslands (Du et al, 2018; Han et al, 2017; Song et al, 2021), and alpine grasslands (Wang et al, 2019) that reported negative N effects on soil respiration. A previous meta‐analysis has found that differences in soil respiration responses to N addition may largely result from diverse responses of root respiration among biomes (Zhou et al, 2014).…”

“…Numerous studies have demonstrated that interannual variability of precipitation amount or soil water availability plays a critical role in regulating temporal variations of soil respiration through controlling root and microbial activities and plant growth (Han et al, 2017; Wan et al, 2007; Zhou et al, 2007). In addition, there is also increasing evidence that plant community is a key driver of soil respiration response in long‐term studies (Du et al, 2018; Xu et al, 2015).…”

Differential Response of Soil Respiration and Total Belowground Carbon Allocation to Simulated Nitrogen and Phosphorus Deposition in Moso Bamboo Forests

“…Regardless of N and P deposition, there were strong monthly variabilities in RS, RA, and RH, which were similar to previous studies [24,53]. Some studies found that temporal variabilities of soil carbon fluxes were driven by precipitation or SM through regulating root and microbial activities [59,60]. However, SM was not the regulating factor controlling RS, RA, and RH, because there were no significant correlations between RS, RA, and RH and SM in the current study (Figure S1).…”

Nitrogen‐Induced Changes in Carbon Fluxes Are Modulated by Water Availability in a Temperate Grassland

“…However, there are also mounting evidence suggest a weak prediction of water availability to the N‐induced changes in ecosystem carbon fluxes (Hooper & Johnson, 1999; Lebauer & Treseder, 2008; Niu et al., 2009; Peng et al., 2017). Although GPP is more sensitive to water availability than R e in grassland (Xia et al., 2009), water may also alleviate (Zhang et al., 2017) or enhance (Han et al., 2017) the negative effects of N enrichment on respiration by mediating N‐induced soil acidification. Through decades of researches, we have only acquired knowledge about comparisons of N‐induced effects in dry or wet conditions, there remain considerable knowledge gap about how the N‐induced changes of carbon fluxes, inter‐ or intra‐annually, will vary with water conditions.…”

“…It reported that N‐induced stimulation of biomass accumulation (Lü et al., 2011) may exert positive and N‐induced soil acidification (Bowman et al., 2008; Fierer & Jackson, 2006; Ye et al., 2018) may exert negative effects on respiration. Therefore, respiration may increase (Peng et al., 2017; Zhang et al., 2017), remain unchanged (Liu et al., 2018), or decrease (Han et al., 2017) due to N enrichment. Different responsive rates of GPP and R e may lead to positive (Niu et al., 2008; Tian et al., 2016; Xia et al., 2009), negative (Bubier et al., 2007; Saarnio et al., 2003), and neutral (Harpole et al., 2007; Huang et al., 2015; López‐Blanco et al., 2018) responses of NEE to N additions.…”