Shift in soil microbial communities with shrub encroachment in Inner Mongolia grasslands, China

He, Ling; Zhang, Jianhua; Chen, Leiyi; Zhu, Yanhui; Shen, Haihua; Fang, Jingyun

doi:10.1016/j.ejsobi.2017.02.004

Cited by 36 publications

(30 citation statements)

References 45 publications

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“…These results contrast with previous studies which found the microbial biomass to be greater in soils beneath shrub canopies than adjacent grasses due to reduced environmental stress and greater stores of SOM (Gallardo and Schlesinger, 1992;Li et al, 2017;Ewing et al, 2007). As ratios between the fungal and bacterial constituents of the microbial 10 community share a negative relationship with soil pH (Bååth and Anderson, 2003), a decline in the fungal PLFA content of shrub soils can be attributed to changes in shrub soil pH which increased with gains in shrub cover (Table 1).…”

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confidence: 56%

“…These plant community changes result in a structurally, physically and biologically different ecosystem which significantly alter the spatial distribution and fluxes of nutrients and the biogeochemical cycling within dryland landscapes, with implications for the ongoing process of land degradation (Eldridge et al, 2011;Michaelides 20 et al, 2012). Nitrogen (N), in particular, is the most significant limiting factor of primary production and decomposition processes in dryland systems after water (Gebauer and Ehleringer, 2000), yet there is currently limited understanding of how ecosystem transformations associated with land degradation changes the distribution, speciation and cycling of N (Browning et al, 2008), as well as the associated soil microbial biomass (Li et al, 2017). As drylands occupy ~40% of the Earth's land surface, changes in the nutrient distributions, patterns and cycling within degrading areas have important implications for 25 biogeochemical cycles at the global scale (Delgado-Baquerizo et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…As the amount of N mineralised during decomposition depends on the C and N stoichiometry of decomposer organisms relative to that of organic matter (Schulten and Schnitzer, 1997), differences in the relative abundance of fungal and bacterial biomass can potentially modulate soil N 10 cycling (Waring et al, 2013). Using the phospholipid fatty acid (PLFA) method, Li et al (2017) demonstrated that the ratio of viable fungi to bacteria for a semiarid grassland was significantly higher in soil under shrubs than for soils in intershrub areas, and that soil microbial biomass was positively correlated with concentrations of total N and available phosphorus (P).…”

Section: Introductionmentioning

confidence: 99%

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Soil nitrogen response to shrub encroachment in a degrading semiarid grassland

Turpin-Jelfs¹,

Michaelides²,

Anesio³

2018

Preprint

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Abstract. Transitions from grass- to shrub-dominated states in drylands by woody plant encroachment represent significant forms of land cover change with the potential to alter the spatial distribution and cycling of soil resources. Yet an understanding of how this phenomenon impacts the soil nitrogen pool, which is essential to primary production in arid and semiarid systems, is poorly resolved. In this study, we quantified how the distribution and speciation of soil nitrogen, as well as rates of free-living biological nitrogen fixation, changed along a gradient of increasing mesquite (Prosopis velutina Woot.) cover in a semiarid grassland of the Southwestern US. Our results show that site-level concentrations of total nitrogen remain unchanged with increasing shrub cover as losses from intershrub areas (sum of grass and bare-soil cover) are proportional to increases in soils under shrub canopies. However, despite the similar carbon-to-nitrogen ratio and microbial biomass of soil from intershrub and shrub areas at each site, site-level concentrations of inorganic nitrogen increase with shrub cover due to the accumulation of ammonium and nitrate in soils beneath shrub canopies. Using the acetylene reduction assay technique, we found increasing ratios of inorganic nitrogen-to-bioavailable phosphorus inhibit rates of biological nitrogen fixation by free-living soil bacteria. Consequently, we conclude that shrub encroachment has the potential to significantly alter the dynamics of soil nitrogen cycling in dryland systems.

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confidence: 56%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Soil nitrogen response to shrub encroachment in a degrading semiarid grassland

Turpin-Jelfs¹,

Michaelides²,

Anesio³

2018

Preprint

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“…The mean annual temperature (MAT) and mean annual precipitation (MAP) at the SEG sites ranged from 0.3°C to 4.9°C and 282 to 376 mm, respectively, in typical grasslands and from 1.8°C to 4.9°C and 200 to 285 mm, respectively, in desert grasslands (Table S1). Climatic data were obtained using interpolation methods based on original climate station data from 1975 to 2005 in Inner Mongolia (Li et al, ). During the period of this study, the vegetation of the study sites was dominated by the herbaceous species Leymus chinensis and Stipa krylovii .…”

Section: Methodsmentioning

confidence: 99%

“…Shrub encroachment typically leads to a transition in land cover from herb‐dominated grasslands to a mosaic landscape of shrub‐encroached grassland (SEG), in which shrub patches are interspersed within a grassy matrix (Chen et al, ). These vegetation changes can alter the quantities and qualities of aboveground and belowground residue inputs as well as the soil microbial community (Knapp et al, ; Li et al, ; Zhou, Boutton, & Wu, ), and can ultimately influence the cycling of carbon (C) and nitrogen (N) in grassland ecosystems (Don, Schumacher, & Freibauer, ; Guo & Gifford, ; Throop & Archer, ).…”

Section: Introductionmentioning

confidence: 99%

Shrub encroachment increases soil carbon and nitrogen stocks in temperate grasslands in China

Shen

Zhou

et al. 2019

Land Degrad Dev

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Shrub encroachment has significant impacts on carbon (C) and nitrogen (N) dynamics of grassland ecosystems, but, how it influences soil organic C (SOC) and soil total N (STN) stocks of grasslands is not well documented, especially in deep soils. Here, we examined these effects by investigating the SOC density (SOCD) and the STN density (STND) at depths of up to 5 m in shrub patches and grassy matrix at 18 grassland sites in Inner Mongolia, China. Our results revealed that 44.0–54.1% of SOC and 65.5–74.8% of STN were stored in soil layers of 100 cm to 500 cm, and that shrub encroachment resulted in a significant accumulation of SOC and STN in shrub patches. The mean SOCD at 0–500 cm soil layers in shrub patches and grassy matrix was 11.34 and 8.39 kg C m−2, respectively, and the mean STND was 2.45 and 2.13 kg N m−2, respectively. These differences between the shrub patches and grassy matrix were equivalent to an increase in the mean SOC and STN stocks of 2.95 kg C m−2 and 0.32 kg N m−2, respectively. Increases in SOCD and STND mainly occurred in 30–300 cm soil layers, and varied between typical grassland and desert grassland. The changes in SOCD and STND exhibited significant negative correlations with temperature and pH and positive correlations with precipitation and plant biomass. Our findings suggest that shrub encroachment can significantly accumulate SOC and STN in deep soils in temperate grasslands, which helps to understand soil C and N dynamics in shrub‐encroached grasslands.

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Effects of shrub encroachment on soil aggregates and organic carbon vary in different grasslands in Inner Mongolia, China

et al. 2021

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Widespread shrub encroachment in grasslands can lead to changes in soil aggregates and soil organic carbon (SOC), especially in deep soils. Soil aggregates physicochemically protect SOC and thus affect soil carbon sequestration. Characterizing the changes in soil aggregates and their organic carbon associated with shrub encroachment is critical for evaluating the ecological consequences of shrub encroachment in different grasslands. In this study, we investigated soil aggregates of various sizes and their associated organic carbon at maximum soil depths of 5 m in shrub patches and neighboring grass matrix in two types (desert and typical) of grasslands in Inner Mongolia, China. The mean weight diameter (MWD) of the soil aggregates was similar between the shrub patches and grass matrix in both grasslands. However, the proportion of each aggregate size fraction to whole soil in the shrub patches was significantly lower than that in the grass matrix in the desert grasslands, while there was no significant difference between the shrub patches and grass matrix in the typical grasslands. In addition, the organic carbon content of aggregates in the shrub patches was greater than that in the grass matrix in deep soil layers (>50 cm) but was lower in the topsoil (0-10 cm depth) in the desert grasslands. However, the organic carbon content of aggregates at all soil depths was greater in shrub patches than in the grass matrix in typical grasslands. Our results suggest that the effects of shrub encroachment on the soil aggregate proportion and associated organic carbon vary at different soil depths and in different grassland types. The results of this study also suggest that it is necessary to determine the size structure and its relation to carbon content for soil aggregates to accurately predict SOC dynamics with shrub encroachment.

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Shift in soil microbial communities with shrub encroachment in Inner Mongolia grasslands, China

Cited by 36 publications

References 45 publications

Soil nitrogen response to shrub encroachment in a degrading semiarid grassland

Soil nitrogen response to shrub encroachment in a degrading semiarid grassland

Shrub encroachment increases soil carbon and nitrogen stocks in temperate grasslands in China

Effects of shrub encroachment on soil aggregates and organic carbon vary in different grasslands in Inner Mongolia, China

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