Characteristics of, and the correlation between, vegetation and N-fixing soil bacteria in alpine grassland showing various degrees of degradation

Jianhong, 李建宏 Li; Xueping, 李雪萍 Li; Hu, 卢虎 Lu; Tuo, 姚拓 Yao; Lide, 王理德 Wang; Chunxiu, 郭春秀 Guo; Shangli, 师尚礼 Shi

doi:10.5846/stxb201604010598

Cited by 2 publications

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“…Additionally, there have been changes in the rate of soil organic matter decomposition and mineralization [20]. Furthermore, there has been a decrease in microbial biomass, N-fixing bacteria [21], and soil enzyme activities [18,22], which have impacted N storage and cycling within these grassland ecosystems along with the occurrence of grassland degradation [23].…”

Section: Introductionmentioning

confidence: 99%

Warming Mitigates the Impacts of Degradation on Nitrogen Allocation between Soil Microbes and Plants in Alpine Meadow

Pang,

Wen,

Jiang

et al. 2024

Agronomy

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In alpine meadows, plants and soil microbes typically engage in competition for nitrogen (N) under N-deficient conditions. However, the acquisition and distribution of N among soil microbes and plants under alpine meadow degradation and climate warming induced by global climate change are still uncharacterized. In this study, we isotope labeled inorganic (NH4+-15N, NO3−-15N) and organic (glycine-15N) N in both degraded and non-degraded plots by using open-top chambers (OTC) to mimic increasing air temperatures. After 6 h, the 15N contents in soil microbes and plants were measured to investigate the effects of degradation and rising air temperature on N allocations in the ecosystems studied. Results showed that alpine meadow degradation significantly reduced soil microbial N accumulation by 52% compared to those in non-degraded plots. In non-degraded plots, warming significantly lowered the organic N levels of soil microbes by 49%, whereas in degraded ones, it reduced both NH4+-15N and NO3−-15N recovery by 80% and 45% on average but increased glycine-15N recovery by 653%. Meanwhile, warming decreased the plant recovery of NH4+-15N and NO3−-15N by 75% and 45% but increased the recovery of glycine-15N by 45% in non-degraded plots. Conversely, in degraded plots, warming markedly lowered NH4+-15N recovery by 40% but increased glycine-15N recovery by 114%. Warming mitigates the effects of alpine meadow degradation on nitrogen allocation among soil microbes and plants. In unwarmed plots, degradation significantly elevated the total 15N recovery ratio of soil microbes to plants by 60%. However, in warmed plots, the impact of degradation on this ratio was reduced. The responses of the 15N recovery ratio of soil microbes and plants to rising temperatures were closely related to alpine meadow quality. In non-degraded areas, warming enhanced the recovery ratio for NH4+-15N by 165% but reduced it for glycine-15N by 66%. Conversely, in degraded plots, warming decreased the recovery ratio for NH4+-15N by 66% but increased it for glycine-15N by 232%. This indicates that warming can increase carbon limitation for soil microbes in degraded alpine meadows, and the restoration of degraded alpine meadows should prioritize restoring carbon accumulation.

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Section: Introductionmentioning

confidence: 99%

Warming Mitigates the Impacts of Degradation on Nitrogen Allocation between Soil Microbes and Plants in Alpine Meadow

Pang,

Wen,

Jiang

et al. 2024

Agronomy

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“…Orr’s research showed that nitrogen addition increases the soil organic carbon content and the abundance of nitrogen fixing bacteria, thereby promoting the nitrogen fixation function of soil microorganisms ( Orr et al, 2012 ). Numerous research results have shown that nitrogen deposition reduces the plant and microbial diversity ( Dai et al, 2018 ; Midolo et al, 2019 ), leading to changes in the structure of nitrogen-fixing microbial communities, which alters the soil nitrogen cycle and the rate of nitrogen fixation, and ultimately affects the plant growth and soil health ( Jianhong et al, 2017 ). Zheng studied the response of soil nitrogen fixation to nitrogen addition in different types of subtropical forests in Dinghushan, China.…”

Section: Introductionmentioning

confidence: 99%

Effects of nitrogen deposition on the rhizosphere nitrogen-fixing bacterial community structure and assembly mechanisms in Camellia oleifera plantations

Liu,

He,

Chen

et al. 2024

Front. Microbiol.

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Increased nitrogen deposition is a key feature of global climate change, however, its effects on the structure and assembling mechanisms of the nitrogen-fixing bacteria present at the root surface remain to be elucidated. In this pursuit, we used NH4NO3 to simulate nitrogen deposition in a 10-year-old Camellia oleifera plantation, and set up four deposition treatments, including control N0 (0 kg N hm−2 a−1), low nitrogen N20 (20 kg N hm−2 a−1), medium nitrogen N40 (40 kg N hm−2 a−1) and high nitrogen N160 (160 kg N hm−2 a−1). The results showed that nitrogen deposition affected the soil nitrogen content and the structure of the nitrogen-fixing bacterial community. Low nitrogen deposition was conducive for nitrogen fixation in mature C. oleifera plantation. With increasing nitrogen deposition, the dominant soil nitrogen-fixing bacterial community shifted from Desulfobulbaceae to Bradyrhizobium. When nitrogen deposition was below 160 kg N hm−2 a−1, the soil organic matter content, total nitrogen content, nitrate nitrogen content, ammonium nitrogen content, urease activity, soil pH and nitrate reductase activity influenced the composition of the nitrogen-fixing bacterial community, but the stochastic process remained the dominant factor. The results indicate that the strains of Bradyrhizobium japonicum and Bradyrhizobium sp. ORS 285 can be used as indicator species for excessive nitrogen deposition.

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Characteristics of, and the correlation between, vegetation and N-fixing soil bacteria in alpine grassland showing various degrees of degradation

Cited by 2 publications

References 0 publications

Warming Mitigates the Impacts of Degradation on Nitrogen Allocation between Soil Microbes and Plants in Alpine Meadow

Warming Mitigates the Impacts of Degradation on Nitrogen Allocation between Soil Microbes and Plants in Alpine Meadow

Effects of nitrogen deposition on the rhizosphere nitrogen-fixing bacterial community structure and assembly mechanisms in Camellia oleifera plantations

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