Composition and variation of soil δ15N stable isotope in natural ecosystems

Shan, Yan; Huang, Mingbin; Suo, Lizhu; Zhao, Xueyong; Wu, Lianhai

doi:10.1016/j.catena.2019.104236

Cited by 24 publications

(16 citation statements)

References 55 publications

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“…The decline in soil δ 15 N values with increasing water availability is in line with previous studies (Amundson et al., 2003; Chadwick et al., 2007; Craine et al., 2015; Peri et al., 2012; Shan et al., 2019; Vitousek, et al., 2019; Wu et al., 2019). This result is also consistent with mechanistic laboratory studies that demonstrate that increasing soil moisture may favor the accumulation of δ 14 N (Yun & Ro, 2014).…”

Section: Discussionsupporting

confidence: 90%

Precipitation is the key determinant of topsoil δ¹⁵N values in southern Patagonia's semiarid rangelands

Peri

Duarte‐Guardia

Amelung

et al. 2022

Vadose Zone Journal

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Nitrogen (N) cycling in rangeland soils could potentially be controlled by water supply, stocking rates, or a range of other variables, such as ecosystem N stocks. To gauge the relative importance and elucidate possible interactions among these factors, we measured many abiotic variables to identify first‐order controls of δ15N for Patagonia's rangeland soils under contrasting historical grazing intensities. The results showed that δ15N values declined as water availability increased. The effects of precipitation and stocking rate on soil δ15N values were additive, and the effect of precipitation far outweighed the effects of grazing pressure. The soil N stock was a weak predictive variable for modeling variation in δ15N of the soil. Earlier assumptions about an inflection point for N cycling and δ15N values related to aridity were not confirmed. We conclude that variation in water availability drives variation in δ15N values irrespective of grazing intensity. We also conclude that meaningful interpretation of δ15N in soil will require a better mechanistic understanding of the interactions between water and N in the vadose zone than we currently possess.

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Section: Discussionsupporting

confidence: 90%

Precipitation is the key determinant of topsoil δ¹⁵N values in southern Patagonia's semiarid rangelands

Peri

Duarte‐Guardia

Amelung

et al. 2022

Vadose Zone Journal

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“…(2) As an indicator that integrates many processes affecting the N cycle, controls on soil δ 15 N are very complicated, including various climatic, edaphic and biological factors [29,32]. Consistently with a previous study on the Chinese Loess Plateau [58], edaphic factors such as SOC, N t and P t strongly influenced soil δ 15 N across our transect. Previous studies demonstrated that soil δ 15 N increased or decreased with N t contents [10,11], but we observed a significant positive logarithmic relationship between soil δ 15 N and N t along the transect.…”

Section: Discussionsupporting

confidence: 86%

Climatic, Edaphic and Biotic Controls over Soil δ13C and δ15N in Temperate Grasslands

Zhao

Wang

et al. 2020

Forests

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Soils δ13C and δ15N are now regarded as useful indicators of nitrogen (N) status and dynamics of soil organic carbon (SOC). Numerous studies have explored the effects of various factors on soils δ13C and δ15N in terrestrial ecosystems on different scales, but it remains unclear how co-varying climatic, edaphic and biotic factors independently contribute to the variation in soil δ13C and δ15N in temperate grasslands on a large scale. To answer the above question, a large-scale soil collection was carried out along a vegetation transect across the temperate grasslands of Inner Mongolia. We found that mean annual precipitation (MAP) and mean annual temperature (MAT) do not correlate with soil δ15N along the transect, while soil δ13C linearly decreased with MAP and MAT. Soil δ15N logarithmically increased with concentrations of SOC, total N and total P. By comparison, soil δ13C linearly decreased with SOC, total N and total P. Soil δ15N logarithmically increased with microbial biomass C and microbial biomass N, while soil δ13C linearly decreased with microbial biomass C and microbial biomass N. Plant belowground biomass linearly increased with soil δ15N but decreased with soil δ13C. Soil δ15N decreased with soil δ13C along the transect. Multiple linear regressions showed that biotic and edaphic factors such as microbial biomass C and total N exert more effect on soil δ15N, whereas climatic and edaphic factors such as MAT and total P have more impact on soil δ13C. These findings show that soil C and N cycles in temperate grasslands are, to some extent, decoupled and dominantly controlled by different factors. Further investigations should focus on those ecological processes leading to decoupling of C and N cycles in temperate grassland soils.

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“…Early on, sources of atmospheric N in Guiyang, one of regions in our study, were urban sewage and agricultural NH y , which was characterized by low δ 15 N (Liu et al, 2008; Qu et al, 2016). During 2006–2017, the dominant atmospheric N compounds and sources changed from 15 N‐depleted NH y (−15 ~ 0‰) to less depleted or 15 N‐enriched NO x (−5 ~ 5‰, Felix & Elliott, 2014; Heaton, 1990; Liu et al, 2008; Rivero‐Villar et al, 2018; Shan et al, 2019) in urban regions (Zhao et al, 2019), which might affect the δ 15 N in leaves. The change in the form of N in deposition was slow and occurred in the later period covered by our study (Yu et al, 2019; Zhao et al, 2019), allowing for decreases in foliar δ 15 N of trees in southern China over the past 90 years.…”

Section: Discussionmentioning

confidence: 99%

Drivers of foliar ¹⁵N trends in southern China over the last century

Tang

Liu

Gilliam

et al. 2022

Global Change Biology

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Foliar stable nitrogen (N) isotopes (δ15N) generally reflect N availability to plants and have been used to infer about changes thereof. However, previous studies of temporal trends in foliar δ15N have ignored the influence of confounding factors, leading to uncertainties on its indication to N availability. In this study, we measured foliar δ15N of 1811 herbarium specimens from 12 plant species collected in southern China forests from 1920 to 2010. We explored how changes in atmospheric CO2, N deposition and global warming have affected foliar δ15N and N concentrations ([N]) and identified whether N availability decreased in southern China. Across all species, foliar δ15N significantly decreased by 0.82‰ over the study period. However, foliar [N] did not decrease significantly, implying N homeostasis in forest trees in the region. The spatiotemporal patterns of foliar δ15N were explained by mean annual temperature (MAT), atmospheric CO2 (PCO2), atmospheric N deposition, and foliar [N]. The spatiotemporal trends of foliar [N] were explained by MAT, temperature seasonality, PCO2, and N deposition. N deposition within the rates from 5.3 to 12.6 kg N ha−1 year−1 substantially contributed to the temporal decline in foliar δ15N. The decline in foliar δ15N was not accompanied by changes in foliar [N] and therefore does not necessarily reflect a decline in N availability. This is important to understand changes in N availability, which is essential to validate and parameterize biogeochemical cycles of N.

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Composition and variation of soil δ15N stable isotope in natural ecosystems

Cited by 24 publications

References 55 publications

Precipitation is the key determinant of topsoil δ¹⁵N values in southern Patagonia's semiarid rangelands

Precipitation is the key determinant of topsoil δ¹⁵N values in southern Patagonia's semiarid rangelands

Climatic, Edaphic and Biotic Controls over Soil δ13C and δ15N in Temperate Grasslands

Drivers of foliar ¹⁵N trends in southern China over the last century

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Composition and variation of soil δ15N stable isotope in natural ecosystems

Cited by 24 publications

References 55 publications

Precipitation is the key determinant of topsoil δ15N values in southern Patagonia's semiarid rangelands

Precipitation is the key determinant of topsoil δ15N values in southern Patagonia's semiarid rangelands

Climatic, Edaphic and Biotic Controls over Soil δ13C and δ15N in Temperate Grasslands

Drivers of foliar 15N trends in southern China over the last century

Contact Info

Product

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Precipitation is the key determinant of topsoil δ¹⁵N values in southern Patagonia's semiarid rangelands

Precipitation is the key determinant of topsoil δ¹⁵N values in southern Patagonia's semiarid rangelands

Drivers of foliar ¹⁵N trends in southern China over the last century