Effects of precipitation exclusion on N2O emissions in a savanna ecosystem in SW China

Li, Jing; Jin, Yang; Liu, Yuntong; Zhang, Yiping; Grace, J. Kusuma; Song, Qinghai; Sha, Liqing; Lin, Yiming; Chen, Aiguo; Li, Peiguang; Fei, Xuehai

doi:10.1016/j.atmosenv.2018.05.035

Cited by 12 publications

(9 citation statements)

References 53 publications

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“…These characteristics determine how the impact translates into soil microclimate (e.g. changes in soil moisture under different drought intensity by Li et al, 2018) and nonlinear microbial responses to resultant stress (McHale, Mitchell, & Bowles, 1998). At the seasonal scale, warming outside the growing season (i.e.…”

Section: Introductionmentioning

confidence: 99%

Terrestrial N₂O emissions and related functional genes under climate change: A global meta‐analysis

Zheng

Wang

et al. 2019

Global Change Biology

151

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Nitrous oxide (N2O) emissions from soil contribute to global warming and are in turn substantially affected by climate change. However, climate change impacts on N2O production across terrestrial ecosystems remain poorly understood. Here, we synthesized 46 published studies of N2O fluxes and relevant soil functional genes (SFGs, that is, archaeal amoA, bacterial amoA, nosZ, narG, nirK and nirS) to assess their responses to increased temperature, increased or decreased precipitation amounts, and prolonged drought (no change in total precipitation but increase in precipitation intervals) in terrestrial ecosystem (i.e. grasslands, forests, shrublands, tundra and croplands). Across the data set, temperature increased N2O emissions by 33%. However, the effects were highly variable across biomes, with strongest temperature responses in shrublands, variable responses in forests and negative responses in tundra. The warming methods employed also influenced the effects of temperature on N2O emissions (most effectively induced by open‐top chambers). Whole‐day or whole‐year warming treatment significantly enhanced N2O emissions, but daytime, nighttime or short‐season warming did not have significant effects. Regardless of biome, treatment method and season, increased precipitation promoted N2O emission by an average of 55%, while decreased precipitation suppressed N2O emission by 31%, predominantly driven by changes in soil moisture. The effect size of precipitation changes on nirS and nosZ showed a U‐shape relationship with soil moisture; further insight into biotic mechanisms underlying N2O emission response to climate change remain limited by data availability, underlying a need for studies that report SFG. Our findings indicate that climate change substantially affects N2O emission and highlights the urgent need to incorporate this strong feedback into most climate models for convincing projection of future climate change.

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Section: Introductionmentioning

confidence: 99%

Terrestrial N₂O emissions and related functional genes under climate change: A global meta‐analysis

Zheng

Wang

et al. 2019

Global Change Biology

151

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“…this effect was found to be stronger in the dry season than in the wet season (Li et al, 2018). It is widely accepted that soil NH 4 + -N and NO 3…”

Section: Introductionmentioning

confidence: 87%

“…Chen et al, 2017;Reichmann et al, 2013). Furthermore, significant changes in desert soil NH 4 + -N and NO 3 À -N were also observed by changing the precipitation (Song et al, 2020), which significantly affected the soil nitrification and denitrification processes and N 2 O emissions (Li et al, 2018).…”

mentioning

confidence: 94%

“…Moreover, a small amount of precipitation (5 mm) has been shown to occasionally boost N 2 O emissions owing mainly to the limitations of the soil NH 4 + ‐N content (Yue, Zuo, et al, 2021). In contrast, N 2 O fluxes in a savanna ecosystem in southwestern China were significantly reduced by decreasing the precipitation; this effect was found to be stronger in the dry season than in the wet season (Li et al, 2018). It is widely accepted that soil NH 4 + ‐N and NO 3 − ‐N are the substrates of soil nitrification and denitrification processes (Barnard et al, 2005; Gu et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, precipitation changes have been shown to profoundly affect soil nitrogen conversion processes, particularly the rates of soil nitrification and denitrification, as well as the contents of NH 4 + ‐N and NO 3 − ‐N in the soil (J. Chen et al, 2017; Reichmann et al, 2013). Furthermore, significant changes in desert soil NH 4 + ‐N and NO 3 − ‐N were also observed by changing the precipitation (Song et al, 2020), which significantly affected the soil nitrification and denitrification processes and N 2 O emissions (Li et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

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No significant change noted in annual nitrous oxide flux under precipitation changes in a temperate desert steppe

Yue

Zuo

et al. 2021

Land Degrad Dev

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As the third most important greenhouse gas, nitrous oxide (N 2 O) poses a significant threat to global warming and the ozone layer. However, the effects of precipitation changes on N 2 O emissions in arid areas remain unclear, particularly in desert steppe environments. Therefore, an in situ control experiment was conducted from July 2018 to July 2020 to examine the N 2 O emissions with changes in precipitation in the Urat Desert Steppe, northwestern China. The results showed that the N 2 O emission rate was relatively low in this desert steppe, at À0.04 to +15.0 μg N m À2 hr À1 with an annual flux of 0.20 ± 0.03 kg N ha À1 . An increasing trend of N 2 O emission was observed in the early growing season (February to June 2019) when the precipitation was increased by 40% and 60% of its natural level. In contrast, no significant change in N 2 O emissions was observed when the precipitation was decreased during the same period. During the middle and late growing season and in the nongrowing season, precipitation changes did not significantly affect N 2 O emissions. In particular, no significant change in the annual N 2 O flux was observed during the entire observation period whether the precipitation was increased or decreased. Furthermore, the results of a structural equation model showed that the most important controlling factor for N 2 O emission is an abundance of key functional ammonia monooxygenase genes of ammonia-oxidizing archaea, which are restricted by the soil NH 4 + -N content, followed by abundances of key functional NO 2 À reductase (nirK) and N 2 O reductase (nosZ) genes. In contrast, the indirect effect of soil moisture on the abundance of nosZ compensated for the direct effect of soil moisture on N 2 O emissions.These results show that the primary and secondary origins of N 2 O emissions are soil ammonia oxidation and soil denitrification processes, respectively. In these two processes, N 2 O emissions are influenced more by the abundance of key functional microorganisms than by soil moisture, which might be limited mainly by the available soil nitrogen. Overall, the N 2 O emissions in the desert steppe environment were not sensitive to precipitation changes and were regulated mainly by nitrogen-related key functional microorganisms.

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Effects of grazing exclusion on soil infiltrability and preferential flow in savannah livestock grazing systems

et al. 2022

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Although the establishment of grazing exclosures is often considered an important strategy of reducing soil degradation, their effect on hydrological functions is still poorly understood, particularly in dry‐hot savanna systems with heavy livestock grazing. In addition, the different roles played by the herb roots and the niche differentiation of woody plant roots induced by the grazing and exclosure in soil hydrological functions are still unclear. This study aimed to evaluate the effect of exclosure management on hydrological functions and services and assess the role of different functional vegetation types in improving these functions and services. The experiments were conducted in the continuous grazing areas and exclosure areas in a savanna ecosystem in Yuanjiang, southwest China. The root biomass of herb and woody plants, soil physical properties, water infiltration, and preferential water flow were measured in each study site. The results showed a significant improvement in soil physical properties with more termite holes, lower soil bulk density, and higher total and non‐capillary soil porosity in exclosure areas compared with grazing ones. As a result, the initial and average water infiltration, and preferential flow significantly increased by 132.76%, 185.31%, and 30.29%, respectively, in exclosure areas compared with the grazing ones. The results also showed that the exclosure significantly improved the soil surface water content by increasing the root biomass of herb and woody plants in the shallow soil layers. Herb plants probably improved water infiltration and insulated evaporation, while woody plants improved lateral preferential water flow paths and accelerated the water exchange between vertical and horizontal soil layers, thereby improving the water availability for different plants. This study demonstrated that the exclosure‐induced restoration and niche differentiation of herb and woody plants, coupled with improved soil structure in exclosures, could promote hydrological function and services and improve water management in savanna systems. Therefore, the grazing exclosures could be expanded periodically and cautiously to prevent soil degradation in the present savanna systems.

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Effects of precipitation exclusion on N2O emissions in a savanna ecosystem in SW China

Cited by 12 publications

References 53 publications

Terrestrial N₂O emissions and related functional genes under climate change: A global meta‐analysis

Terrestrial N₂O emissions and related functional genes under climate change: A global meta‐analysis

No significant change noted in annual nitrous oxide flux under precipitation changes in a temperate desert steppe

Effects of grazing exclusion on soil infiltrability and preferential flow in savannah livestock grazing systems

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Effects of precipitation exclusion on N2O emissions in a savanna ecosystem in SW China

Cited by 12 publications

References 53 publications

Terrestrial N2O emissions and related functional genes under climate change: A global meta‐analysis

Terrestrial N2O emissions and related functional genes under climate change: A global meta‐analysis

No significant change noted in annual nitrous oxide flux under precipitation changes in a temperate desert steppe

Effects of grazing exclusion on soil infiltrability and preferential flow in savannah livestock grazing systems

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Terrestrial N₂O emissions and related functional genes under climate change: A global meta‐analysis

Terrestrial N₂O emissions and related functional genes under climate change: A global meta‐analysis