Frequency and intensity of nitrogen addition alter soil inorganic sulfur fractions, but the effects vary with mowing management in a temperate steppe

Abstract. Sulfur (S) availability plays a vital role in driving functions of terrestrial ecosystems, which can be largely affected by soil inorganic S fractions and pool size. Enhanced nitrogen (N) input can significantly affect soil S availability, but it still remains largely unknown if the N effect varies with frequency of N addition and mowing management in grasslands. To investigate changes in the soil S pool and inorganic S fractions (soluble S, adsorbed S, available S, and insoluble S), we conducted a field experiment with different frequencies (two times per year vs. monthly additions per year) and intensities (i.e., 0, 1, 2, 3, 5, 10, 15, 20, and 50 g N m−2 yr−1) of NH4NO3 addition and mowing (unmown vs. mown) over 6 years in a temperate grassland of northern China. Generally, N addition frequency, N intensity, and mowing significantly interacted with each other to affect most of the inorganic S fractions. Specifically, a significant increase in soluble S was only found at high N frequency with the increasing intensity of N addition. Increasing N addition intensity enhanced adsorbed S and available S concentrations at low N frequency in unmown plots; however, both fractions were significantly increased with N intensity at both N frequencies in mown plots. The high frequency of N addition increased the concentrations of adsorbed S and available S in comparison to the low frequency of N addition only in mown plots. Changes in soil S fractions were mainly related to soil pH, N availability, soil organic carbon (SOC), and plant S uptake. Our results suggested that N input could temporarily replenish soil-available S by promoting dissolution of soil-insoluble S with decreasing soil pH and mineralization of organic S due to increasing plant S uptake. However, the significant decrease in organic S and total S concentrations with N addition intensity in mown plots indicated that N addition together with biomass removal would eventually cause soil S depletion in this temperate grassland in the long term. Our results further indicated that using large and infrequent N additions to simulate N deposition can overestimate the main effects of N deposition and mowing management on soil S availability in semiarid grasslands.

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Frequency and intensity of nitrogen addition alter soil inorganic sulfur fractions but the effects vary with mowing management in a temperate steppe

10.5194/bg-2018-526 ◽

2019 ◽

Author(s):

Tianpeng Li ◽

Heyong Liu ◽

Ruzhen Wang ◽

Xiao-Tao Lü ◽

Junjie Yang ◽

...

Keyword(s):

Soil Ph ◽

Inorganic Nitrogen ◽

Nitrogen Addition ◽

N Deposition ◽

Temperate Grassland ◽

Pool Size ◽

Water Soluble ◽

N Addition ◽

N Input ◽

Soil Inorganic

Abstract. Sulfur (S) availability plays a vital role in driving functions of terrestrial ecosystems, which can be largely affected by soil inorganic S fractions and pool size. Enhanced ecosystem nitrogen (N) input can significantly affect soil S availability, but it still remains largely unknown if the N effect varies with frequency of N addition and mowing management in grasslands. To investigate changes in soil S pool and inorganic S fractions (water-soluble S, adsorbed S, available S, and insoluble S), we conducted a field experiment with different frequencies (twice vs. monthly additions per year) and intensities (i.e. 0, 1, 2, 3, 5, 10, 15, 20, and 50 g N m−2 year−1) of NH4NO3 addition and mowing (unmowing vs. mowing) over six years in a temperate grassland of northern China. Soil water-soluble and adsorbed S concentrations significantly increased, while insoluble S decreased with increasing intensity of N input. Such changes were correlated with soil pH and total inorganic nitrogen (TIN) concentration. High frequency of N addition increased the concentrations of water-soluble S, adsorbed S and available S as compared to low frequency of N addition in mown plots. Mowing significantly decreased all soil inorganic S fractions by reducing S replenishment via plant residue return. Mowing significantly interacted with both N addition intensity and frequency to affect inorganic S fractions, in that adsorbed S and available S showed no response to N addition intensity in unmown plots but significantly increased in mown plots under high N frequency. Mowing interacted with N addition intensity to decrease soil S pool size, suggesting that biomass removal under N input would cause soil S depletion in this temperate grassland. Nitrogen addition could replenish soil available S by promoting dissolution of soil insoluble S with decreasing soil pH and mineralization of organic S due to increasing plant S uptake. Our results further indicated that using large and infrequent N addition to simulate N deposition can overestimate the main effects of N deposition and mowing on soil S availability in semi-arid grasslands.

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Fate of atmospheric nitrogen depositions in two Italian temperate mountain forests assessed by isotopic analysis

10.5194/egusphere-egu2020-13067 ◽

2020 ◽

Author(s):

Luca Da Ros ◽

Maurizio Ventura ◽

Mirco Rodeghiero ◽

Damiano Gianelle ◽

Giustino Tonon

Keyword(s):

Forest Canopy ◽

N Uptake ◽

Isotopic Signature ◽

N Deposition ◽

Forest Growth ◽

N Availability ◽

N Addition ◽

Total N ◽

Sequestration Potential ◽

Soil And Water

Abstract. Forests ability to store carbon is strongly connected with the amount of nitrogen (N) that forest ecosystems can retain; N is indeed considered the most limiting nutrient for terrestrial ecosystem's net primary productivity. Since the industrial revolution, human activities have more than doubled the rate of N input into the nitrogen cycle and this could alleviate N limitation thus stimulating plant growth. However, it has been suggested that when N availability exceeds biotic demand and abiotic sinks, additional N can trigger a negative cascade effect: nutrient imbalance, reduced productivity, increased losses of N, eutrophication and acidification of soil and water, leading toward forest decline and net greenhouse gases emissions. The consequences of increased N deposition on forest depend in large share on the fate of N in the ecosystem, which can be simulated and quantified by a fertilization at a known isotopic signature. Nevertheless, most of the tracer experiments performed so far added the fertilizer directly to the forest floor, neglecting the potential role of N uptake by the forest canopy. In the Italian Alps, we are conducting an experiment where both types of N additions (above and below the canopy layer) are performed in two different forest stands, to understand if canopy fertilization better simulates ecological consequences of increased atmospheric N deposition. These field-scale manipulation experiments are willing to test two different hypotheses: i) the N uptake by trees in the above-canopy N addition experimental sites is higher than under-canopy N addition ii) forest growth rate varies with the type of treatment. To describe the fate of the applied N, stable isotope techniques have been adopted: the forest sites, fertilized with NH4NO3 at a known isotopic signature, are sampled for all the ecosystem components (plant, soil and water) periodically to determine the total N content and its isotopic signature. The &#948;15N values permit to calculate the recovery of N-fertilizer in tree tissues, soil and leaching-water, allowing us to understand how N allocation varies under these two fertilization strategies and how this affects C sequestration potential. Results regarding the short-term effects over the first 6 years of data collection will be presented.

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Nitrogen Additions Retard Nutrient Release from Two Contrasting Foliar Litters in a Subtropical Forest, Southwest China

Forests ◽

10.3390/f11040377 ◽

2020 ◽

Vol 11 (4) ◽

pp. 377 ◽

Cited By ~ 2

Author(s):

Liyan Zhuang ◽

Qun Liu ◽

Ziyi Liang ◽

Chengming You ◽

Bo Tan ◽

...

Keyword(s):

Litter Decomposition ◽

Critical Role ◽

C:N Ratio ◽

Terrestrial Ecosystems ◽

N Deposition ◽

Decay Rates ◽

N Addition ◽

K Value ◽

P Release ◽

N Additions

Litter decomposition plays a critical role in regulating biogeochemical cycles in terrestrial ecosystems and is profoundly impacted by increasing atmospheric nitrogen (N) deposition. Here, a N manipulation experiment was conducted to explore the effects of N additions (0 kg N ha−1 yr−1, 20 kg N ha−1 yr−1 and 40 kg N ha−1 yr−1) on decay rates and nutrients release of two contrasting species, the evergreen and nutrient-poor Michelia wilsonii and the deciduous and nutrient-rich Camptotheca acuminata, using a litterbag approach at the western edge of the Sichuan Basin of China. The decay rate and the mineralization of N and phosphorus (P) was faster in nutrient-rich C. acuminata litter than in nutrient-poor M. wilsonii litter, regardless of N regimes. N additions tended to decrease the decay constant (k value) in M. wilsonii litter, but had no effect on C. acuminata litter. N additions had no significant effects on carbon (C) release of both litter types. N additions showed negative effects on N and P release of M. wilsonii litter, particularly in the late decomposition stage. Moreover, for C. acuminata litter, N additions did not affect N release, but retarded P release in the late stage. N additions did not affect the C:N ratio in both litter types. However, N additions—especially high-N addition treatments—tended to reduce C:P and N:P ratios in both species. The effect of N addition on N and P remaining was stronger in M. wilsonii litter than in C. acuminata litter. The results of this study indicate that N additions retarded the nutrients release of two foliar litters. Thus, rising N deposition might favor the retention of N and P via litter decomposition in this specific area experiencing significant N deposition.

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Increasing microbial carbon use efficiency with nitrogen addition resulting from plant-mineral interaction

10.5194/egusphere-egu21-845 ◽

2021 ◽

Author(s):

Xuehui Feng ◽

Jie Hu ◽

Yuanhe Yang ◽

Leiyi Chen

Keyword(s):

Microbial Growth ◽

Global Environmental Change ◽

Terrestrial Ecosystems ◽

Metabolic Parameter ◽

N Availability ◽

Microbial Physiology ◽

Soil C ◽

Carbon Use Efficiency ◽

N Input ◽

Use Efficiency

Elucidating the&#160;mechanisms underlying the changes in microbial physiology under anthropogenic nitrogen (N) input&#160;is of fundamental importance for understanding the carbon-N interaction under global environmental change. Carbon use efficiency (CUE), the ratio of microbial growth to assimilation, represents&#160;a critical&#160;microbial metabolic parameter&#160;that&#160;controls the fate of soil C.&#160;Despite the recognized importance of mineral protection&#160;as a driver of soil C cycling in terrestrial ecosystems, little is known on how mineral-organic association&#160;will modulate the response of microbial CUE to increasing N availability. Here, by combining a 6-year N&#8208;manipulation experiment and 18O isotope incubation, mineral analysis and a two-pool C decomposition model, we evaluate how N-induced modification in mineral protection affect the changes in microbial growth, respiration and CUE. Our results showed&#160;that microbial CUE increased under N enrichment due to the enhanced microbial growth and decreased respiration. Such changes&#160;in microbial physiology further led to a significant decrease in&#160;CO2-C release from the slow C pool&#160;under high N&#160;input. More importantly, the disruption in mineral-organic association induced by elevated root exudates is the foremost reason for the enhanced&#160;microbial growth and CUE&#160;under high N input. Taken together, these findings provide an empirical evidence for the linkage between soil&#160;mineral protection&#160;and&#160;microbial physiology, and highlight the need to consider the plant-mineralogy-microbial&#160;interactions&#160;in Earth system models to improve the prediction of soil C fate under global N deposition.

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Increased microbial sequestration of soil organic carbon under nitrogen deposition over China’s terrestrial ecosystems

Ecological Processes ◽

10.1186/s13717-020-00260-7 ◽

2020 ◽

Vol 9 (1) ◽

Author(s):

Shu Liao ◽

Siyi Tan ◽

Yan Peng ◽

Dingyi Wang ◽

Xiangyin Ni ◽

...

Keyword(s):

Meta Analysis ◽

Terrestrial Ecosystems ◽

N Deposition ◽

N Addition ◽

Soil Organic C ◽

Organic C ◽

Soil Microbial ◽

Biomass Turnover ◽

Microbial Residues ◽

Stimulation Of

Abstract Background China’s terrestrial ecosystems have been receiving increasing amounts of reactive nitrogen (N) over recent decades. External N inputs profoundly change microbially mediated soil carbon (C) dynamics, but how elevated N affects the soil organic C that is derived from microbial residues is not fully understood. Here, we evaluated the changes in soil microbial necromass C under N addition at 11 forest, grassland, and cropland sites over China’s terrestrial ecosystems through a meta-analysis based on available data from published articles. Results Microbial necromass C accounted for an average of 49.5% of the total soil organic C across the studied sites, with higher values observed in croplands (53.0%) and lower values in forests (38.6%). Microbial necromass C was significantly increased by 9.5% after N addition, regardless of N forms, with greater stimulation observed for fungal (+ 11.2%) than bacterial (+ 4.5%) necromass C. This increase in microbial necromass C under elevated N was greater under longer experimental periods but showed little variation among different N application rates. The stimulation of soil microbial necromass C under elevated N was proportional to the change in soil organic C. Conclusions The stimulation of microbial residues after biomass turnover is an important pathway for the observed increase in soil organic C under N deposition across China’s terrestrial ecosystems.

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Interactive effect of climate warming and nitrogen deposition may shift the dynamics of native and invasive species

Journal of Plant Ecology ◽

10.1093/jpe/rtaa071 ◽

2020 ◽

Author(s):

Guang-Qian Ren ◽

Chris B Zou ◽

Ling-Yun Wan ◽

Jacob H Johnson ◽

Jian Li ◽

...

Keyword(s):

Invasive Species ◽

Climate Warming ◽

Native Species ◽

Interactive Effect ◽

N Deposition ◽

Effect Of Temperature ◽

N Availability ◽

N Addition ◽

Artemisia Argyi ◽

Species Dynamics

Abstract Aims Projections of invasive species expansion under a warmer world often do not explicitly consider the concurring nitrogen (N) deposition. It remains largely unknown how the convoluted effect of climate warming and N deposition will shift the native and invasive species dynamics. Here, we hypothesize that the concurring increases in N and temperature would promote growth of invasive species greater than that of native species. Methods A controlled greenhouse experiment was conducted to quantify the growth response of an invasive species (Solidago canadensis L.) and a co-existing native species (Artemisia argyi Levl. et Van) under the effects of climate warming, N deposition and their interactions. Important Findings Due to the strong positive effect of N addition, the interactive effect of temperature increase and N addition resulted in an overall significant increase in growth of both invasive and native species, demonstrating that these manipulations may make microhabitats more favorable to plant growth. However, the relative increases in biomass, height and diameter of invasive S. canadensis were significantly lower than those of native A. argyi. This suggests that the vegetative growth superiority of invasive S. canadensis over the native species A. argyi is reduced by the enhanced N availability in the warmer world. Therefore, the inclusion of N deposition may mitigate the projection of invasive species S. canadensis expansion under climate warming.

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Nitrogen Addition Exacerbates the Negative Effect of Throughfall Reduction on Soil Respiration in a Bamboo Forest

Forests ◽

10.3390/f12060724 ◽

2021 ◽

Vol 12 (6) ◽

pp. 724

Author(s):

Yi Wang ◽

Shirong Liu ◽

Junwei Luan ◽

Chen Chen ◽

Chunju Cai ◽

...

Keyword(s):

Soil Respiration ◽

Global Climate ◽

N Deposition ◽

Interactive Effects ◽

Carbon Limitation ◽

N Availability ◽

Bamboo Forest ◽

N Addition ◽

Negative Effect ◽

Throughfall Reduction

Impacts of drought events and nitrogen (N) deposition on forests are increasingly concerning in the context of global climate change, but their effects, in particular, their interactive effects on soil respiration and its components remain unclear. A two-factor random block field experiment was conducted at a subtropical Moso bamboo forest in Southwest China to explore the response of soil respiration (Rs), autotrophic respiration (Ra), and heterotrophic respiration (Rh) to throughfall re-duction and N addition. Our results showed that throughfall reduction significantly decreased Rs, which is mainly attributed to the decrease in Ra as a result of the decline in fine roots biomass. The N addition led to microbial carbon limitation hence significantly decreased Rh, and thus Rs. We also observed the negative effect of throughfall reduction on Rs was exacerbated by N addition, which is attributed to the significant reduction in Ra under the interaction between throughfall reduction N addition. Our findings suggest that Ra tended to respond more sensitively to potential drought, while Rh responds more sensitively to N deposition, and consequently, increased soil N availability caused by N deposition might aggravate the negative effect of expected drought on soil carbon cycling.

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Nitrogen Deposition Effects on Soil Properties, Microbial Abundance, and Litter Decomposition Across Three Shrublands Ecosystems From the Mediterranean Basin

Frontiers in Environmental Science ◽

10.3389/fenvs.2021.709391 ◽

2021 ◽

Vol 9 ◽

Author(s):

Mauro Lo Cascio ◽

Lourdes Morillas ◽

Raúl Ochoa-Hueso ◽

Manuel Delgado-Baquerizo ◽

Silvana Munzi ◽

...

Keyword(s):

Litter Decomposition ◽

Soil Ph ◽

Mediterranean Basin ◽

Field Experiments ◽

Chemical Properties ◽

N Deposition ◽

Microbial Abundance ◽

N Addition ◽

The Mediterranean ◽

The Mediterranean Basin

Atmospheric nitrogen (N) inputs in the Mediterranean Basin are projected to increase due to fossil fuel combustion, fertilizer use, and the exacerbation of agricultural production processes. Although increasing N deposition is recognized as a major threat to ecosystem functioning, little is known about how local environmental conditions modulate ecosystem function response to N addition, particularly in the context of Mediterranean-Basin ecosystems. Here, we assess how N addition affects important ecosystem properties associated with litter decomposition, soil physical-chemical properties, soil extracellular enzymatic activity and microbial abundance across three long-term N addition experimental sites in the Mediterranean Basin. Sites were located in El Regajal (Madrid, Spain), Capo Caccia (Alghero, Italy), and Arrábida (Lisbon, Portugal) and are all representative of Mediterranean shrublands. No common pattern for litter decomposition process or other studied variables emerged among the control plots of the studied sites. Nitrogen supply only affected soil pH, a major driver of decomposition, in two out of three experimental sites. Moreover, when we explored the role of N addition and soil pH in controlling litter decay, we found that the effects of these factors were site-dependent. Our results point out to local ecosystem features modulating N addition effects in controlling litter decomposition rates in Mediterranean ecosystems, suggesting that the responses of soil functioning to N deposition are site-dependent. These findings provide further knowledge to understand contrasting ecosystem responses to N additions based on a single field experiments.

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Effects of nitrogen deposition on growing-season soil methane sink across global forest biomes

10.5194/bg-2019-29 ◽

2019 ◽

Cited By ~ 1

Author(s):

Enzai Du ◽

Nan Xia ◽

Wim de Vries

Keyword(s):

Boreal Forest ◽

Specific Effect ◽

Terrestrial Ecosystems ◽

Growing Season ◽

N Deposition ◽

N Addition ◽

Ch4 Flux ◽

Subtropical Forests ◽

Low Level ◽

Ch4 Uptake

Abstract. Anthropogenic alteration of global nitrogen (N) deposition has resulted in profound impacts on soil fluxes of greenhouse gases in terrestrial ecosystems. However, the response of soil methane (CH4) flux to N deposition remains poorly quantified in global forest. Based on a synthesis of experimental results from literature, we evaluated the effects of N deposition on growing-season soil CH4 flux across forest biomes. A distinction was made between low-level N addition that is comparable with the worldwide range in N deposition ( 60 kg N−1 yr−1. The results showed that growing-season soil CH4 flux was significantly affected by N additions, the value being dependent on the N addition level and forest biome. Low-level N addition significantly increased growing-season soil CH4 uptake in boreal forest, while an opposite effect occurred in temperate and subtropical forests. However, high-level N addition significantly decreased growing-season soil CH4 uptake across boreal, temperate, and subtropical forests. At biome scale, current N deposition was estimate to increase growing-season soil CH4 sink by 0.029 Tg CH4 in boreal forest, while it decreased growing-season soil CH4 sink by 0.025 Tg CH4 and 0.051 Tg CH4 in temperate and subtropical forests, respectively. This work improves our understanding of biome-specific effect of N deposition on soil CH4 uptake and identifies knowledge gaps in the effect of N deposition on soil CH4 flux in tropical forest.

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Elevated nitrogen deposition may advance invasive weed, Solidago canadensis, in calcareous soils

Journal of Plant Ecology ◽

10.1093/jpe/rtz019 ◽

2019 ◽

Vol 12 (5) ◽

pp. 846-856 ◽

Cited By ~ 1

Author(s):

Ling-Yun Wan ◽

Shan-Shan Qi ◽

Chris B Zou ◽

Zhi-Cong Dai ◽

Guang-Qian Ren ◽

...

Keyword(s):

Native Species ◽

Environmental Changes ◽

Calcareous Soils ◽

N Deposition ◽

N Availability ◽

P Availability ◽

Solidago Canadensis ◽

N Addition ◽

Invasive Weed ◽

P Acquisition

Abstract Aims Change in nitrogen (N) availability regulates phosphorus (P) acquisition and potentially alters the competition among native species and invasive weeds. This study determines how current and projected N deposition affect the growth, the intraspecific and interspecific competitive ability of native and invasive plants in calcareous soils with low P availability. Methods A controlled greenhouse experiment was conducted using sparingly soluble hydroxyapatite (HAP) to simulate the calcareous soils with low P availability. The growth and competitive intensity between an invasive weed (Solidago canadensis) and a native weed (Pterocypsela laciniata) exposed to two levels of N addition representative of current and future N deposition in China were experimentally determined. Important Findings P acquisition and the growth of both S. canadensis and P. laciniata growing alone significantly increased with increasing N level. However, the effect of N addition was reduced when intraspecific or interspecific competition existed. N addition altered the competitive relationship between S. canadensis and P. laciniata allowing S. canadensis to out-compete P. laciniata due to variation in P acquisition from HAP. Elevated N deposition might assist the invasion of S. canadensis in the widely distributed calcareous soils under environmental changes.

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