Grazing is a major modulator of biodiversity and productivity in grasslands. However, our understanding of grazing-induced changes in below-ground communities, processes, and soil productivity is ...limited. Here, using a long-term enclosed grazing meadow steppe, we investigated the impacts of grazing on the soil organic carbon (SOC) turnover, the microbial community composition, resistance and activity under seasonal changes, and the microbial contributions to soil productivity.
The results demonstrated that grazing had significant impacts on soil microbial communities and ecosystem functions in meadow steppe. The highest microbial α-diversity was observed under light grazing intensity, while the highest β-diversity was observed under moderate grazing intensity. Grazing shifted the microbial composition from fungi dominated to bacteria dominated and from slow growing to fast growing, thereby resulting in a shift from fungi-dominated food webs primarily utilizing recalcitrant SOC to bacteria-dominated food webs mainly utilizing labile SOC. Moreover, the higher fungal recalcitrant-SOC-decomposing activities and bacterial labile-SOC-decomposing activities were observed in fungi- and bacteria-dominated communities, respectively. Notably, the robustness of bacterial community and the stability of bacterial activity were associated with α-diversity, while this was not the case for the robustness of fungal community and its associated activities. Finally, we observed that microbial α-diversity rather than SOC turnover rate can predict soil productivity.
Our findings indicate the strong influence of grazing on soil microbial community, SOC turnover, and soil productivity and the important positive role of soil microbial α-diversity in steering the functions of meadow steppe ecosystems.
Abstract
Background
The role of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the pathogenesis of testicular damage is uncertain.
Methods
We investigated the virological, ...pathological, and immunological changes in testes of hamsters challenged by wild-type SARS-CoV-2 and its variants with intranasal or direct testicular inoculation using influenza virus A(H1N1)pdm09 as control.
Results
Besides self-limiting respiratory tract infection, intranasal SARS-CoV-2 challenge caused acute decrease in sperm count, serum testosterone and inhibin B at 4–7 days after infection; and chronic reduction in testicular size and weight, and serum sex hormone at 42–120 days after infection. Acute histopathological damage with worsening degree of testicular inflammation, hemorrhage, necrosis, degeneration of seminiferous tubules, and disruption of orderly spermatogenesis were seen with increasing virus inoculum. Degeneration and death of Sertoli and Leydig cells were found. Although viral loads and SARS-CoV-2 nucleocapsid protein expression were markedly lower in testicular than in lung tissues, direct intratesticular injection of SARS-CoV-2 demonstrated nucleocapsid expressing interstitial cells and epididymal epithelial cells, While intranasal or intratesticular challenge by A(H1N1)pdm09 control showed no testicular infection or damage. From 7 to 120 days after infection, degeneration and apoptosis of seminiferous tubules, immune complex deposition, and depletion of spermatogenic cell and spermatozoa persisted. Intranasal challenge with Omicron and Delta variants could also induce similar testicular changes. This testicular damage can be prevented by vaccination.
Conclusions
SARS-CoV-2 can cause acute testicular damage with subsequent chronic asymmetric testicular atrophy and associated hormonal changes despite a self-limiting pneumonia in hamsters. Awareness of possible hypogonadism and subfertility is important in managing convalescent coronavirus disease 2019 in men.
Severe acute respiratory syndrome coronavirus 2 intranasal infection causes testicular damage and associated hormonal changes despite a self-limiting pneumonia in hamsters. Awareness of possible hypogonadism and subfertility is important in managing convalescent coronavirus disease 2019 in males.
•The mean annual ecosystem respiration rate decreased linearly with increasing grazing intensity and time.•Grazing substantially modified relationships between ecosystem respiration and ...biotic-abiotic factors, with canopy height, soil moisture, and soil temperature from un-grazed to heavily-grazed plots.•Precipitation was the major factor regulating the inter-annual pattern of ecosystem respiration, irrespective of grazing intensity.•Grazing-resultant changes in plant biomass were the most principal mechanism underlying the effects of gradient grazing on ecosystem respiration of the meadow steppe ecosystem.
Understanding the effects of livestock grazing on ecosystem respiration (Re) of grassland ecosystems is critical for accurately assessing the feedback of grazing management to climate change. We examined ecosystem respiration in response to varying cattle grazing intensities during growing seasons from 2009 to 2018 in a meadow steppe ecosystem of eastern Inner Mongolia. We found that ungrazed swards had the highest mean annual Re rate, with seasonal CVs in Re ranging from 37.53% to 46.04% for all treatments. When all treatments were analysed as a whole, we identified a significant positive relationship between the annual Re rate and annual peak value of standing plant aboveground biomass. Our findings showed that controlling factors on the mean annual Re differed substantially with grazing intensity. In ungrazed and lightly-grazed plots (G0.00 and G0.23), the mean annual Re rate was controlled mainly by canopy height and/or rainfall, while it was controlled more predominantly by contents of NH4+-N and available phosphorus in moderately and heavily grazed plots. We detected significant positive relationships of the annual Re rate with rainfall, soil moisture, ammonium nitrogen, and soil available phosphorus during the entire study period, whereas significant negative relationships were detected between the annual ecosystem respiration rate and the mean growing season temperature, irrespective of grazing intensity. Our findings revealed that grazing could substantially simplify the relationship between the mean annual Re rate and biotic and abiotic parameters. It may be concluded that the relationship between the annual Re rate and the standing crop aboveground biomass was a principal mechanism underlying the effects of gradient grazing on the Re of Chinese meadow steppe ecosystems.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The variation in soil organic carbon density (SOCD) has been widely documented at various spatial and temporal scales. However, an accurate method for examining the attribution of explanatory factors ...for change in SOCD is still lacking. This study aims to attribute and quantify the key climatic factors, anthropogenic activities, and soil properties associated with SOCD change in the native grasslands of Inner Mongolia, China, by comparing data between the 1960s and the 2010s. In 2007 and 2011, we resampled 142 soil profiles which were originally sampled during 1963–1964 in the native grasslands of Inner Mongolia. SOCD was determined in A horizon (eluvial horizon) of the soil. We selected the explanatory factors based on a random forest method, and explored the relationships between SOCD change and each of the explanatory factors using a linear mixed model. Our results indicated that the change in SOCD varied from the east to the west of Inner Mongolia, and SOCD was 18% lower in the 2010s than in the 1960s. The lower SOCD in the 2010s may primarily be attributed to the increasing in mean annual water surface evaporation, which explained approximately 10% and 50% of the total variation and explainable variation in the change in SOCD, respectively. The sand content of the soil is also a significant explanatory factor for the decrease in SOCD, which explained about 4% and 21% of the total variation and explainable variation in the change in SOCD, respectively. Furthermore, the collection of quantitative information on grazing frequency and duration may also help to improve our understanding of the anthropogenic factors that govern the change in SOCD.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
By altering plant and soil properties and microclimate environments, grazing has a profound influence on the structure and function of grassland ecosystems. However, few studies have addressed the ...potential grazing effects on snow accumulation and subsequent spring soil water after snow melting and soil thawing. In this study, vegetation properties, snow accumulation and soil water were measured in experimental plots subjected to 8 years of cattle grazing comprising six different grazing intensity treatments in a typical temperate grassland in eastern Eurasia. The results indicated that heavy grazing reduced the snow depth by 51% and the snow mass by 40%. Snow accumulation first rapidly increased but then remained relatively stable with increases in both the aboveground biomass and canopy height. An obvious inflection point occurred at approximately 200 g m−2 aboveground biomass and at a 12.5 cm canopy height. The obvious difference in soil water content between the heavily grazed and ungrazed treatments occurred mainly in the spring after snow melting and soil thawing. The spring soil water content (0–30 cm) reached 31.5% in the ungrazed treatment (G0), which was 1.7 times that in the heavily grazed treatment (G0.92). The soil water content increased exponentially with increasing vegetation properties (aboveground biomass, canopy height and canopy cover), and a similar trend occurred with increasing snow mass and snow depth. Our structural equation modeling showed that both vegetation properties and snow accumulation had significant positive effects on spring soil water. By removing vegetation, grazing at increased intensities had significant, indirect suppressive effects on snow accumulation and spring soil water. Therefore, to obtain increased amounts of snow accumulation and spring soil water, land managers should consider reducing the grazing intensity or leaving some plots ungrazed.
Structural equation model depicting the effects of grazing, vegetation (biomass, height and cover) and snow accumulation (mass and depth) on the soil water content (0–30 cm) in the spring (April 20). The width of the arrows is proportional to the path coefficient, with continuous blue (positive) and red (negative) lines indicating the signs of the relationships. The strength of the path coefficient is presented for each pathway. Nonsignificant pathways have been omitted for clarity. The proportion of variance explained (R2) appears above the soil water in the model. χ2 = 6.531, df = 9, p = 0.686, GFI = 0.916, RMSEA = 0.00. Display omitted
•By removing vegetation, overgrazing reduced snow accumulation.•Snow accumulation first increased and then remained stable with increasing AGB.•Grazing altered soil water mainly in the spring after the snow melted and the soil thawed.•By decreasing vegetation and snow accumulation, grazing reduced spring soil water.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Soil organic carbon (SOC) is the most critical component of global carbon cycle in grassland ecosystems. There has been growing interest in understanding SOC dynamics and driving forces of grassland ...biomes at various temporal and spatial scales. Up to now, estimates of long‐term and large‐scale changes in SOC of grassland biomes have been mostly based on modeling approaches and manipulative experiments, rather than direct measurements. During 2007–2011, we repeated 141 soil profiles of the sampling in 1963–1964 (up to 1‐m depth) to quantify the long‐term changes of SOC storage in the major grassland types of Inner Mongolia in order to tease apart the relative contributions of climate change and grazing. We found that SOC decreased in all soil types, except in the eolian sandy soils, from 1963 to 2007, with an average reduction rate of 1.8 kg C m−2 (~22.9% or 0.52% year−1) in the grassland biome of Inner Mongolia. We quantitatively clustered the soils into four groups using principal component analysis (PCA) and detected clear spatial dependency of the changes on climate and grazing. The climate change was responsible for 15.3–34.9% of the total SOC variations, whereas grazing intensity accounted for <9.5% of the changes. Our findings indicated that climate change, rather than grazing, was the primary forcing for the changes in SOC of Inner Mongolia grasslands. We presume that other driving forces, such as changes in nongrazing‐resultant wind erosion and atmospheric nitrogen deposition, might have played a role albeit their effects need to be further examined.
Key Points
SOC decreased at an average rate of 0.52% year−1 in the grassland biome of Inner Mongolia
Climate change rather than grazing was the major contributor to long‐term soil carbon losses
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
•Grazing significantly altered the magnitude and dynamics of soil temperature and moisture.•Soil temperature increased in the warm season, but decreased in the cold season, with grazing ...intensity.•Grazing reduced the soil water storage, especially in the early growing season.
Few studies have addressed the potential grazing effects on microclimate, such as surface temperature and moisture, and their feedback effects on grassland function. A continuous, approximately three-year long study was conducted in experimental plots of various grazing intensities, and in situ soil temperature and moisture were measured. The results indicated that grazing significantly altered soil temperature and moisture. Soil temperature increased exponentially with increasing grazing intensity in the warm season due to the removal of aboveground biomass (AGB) and decreased linearly with increasing grazing intensity in the cold season due to decreases in both AGB and wind-blown snow accumulation. Heavy grazing increased soil temperature (10 cm depth) by an average of 2.6 °C from April to October (the largest hourly temperature increase was 8.8 °C), representing a soil warming effect 3.7 times that of global warming. Our findings showed that, compared with ungrazed plots, grazed plots had decreased soil water storage due to less winter snow accumulation, especially in the early growing season (EGS) because of the smaller amount of winter snow accumulation than in ungrazed plots. In the EGS, the average water storage in the 0–100 cm layer of the ungrazed plots was 23.3%, which was 1.3–1.8 times that of the grazed plots. Our results showed that grazing also produced warming and drying effects on grassland soil. The long-term feedback effects of grazing-induced soil warming and drying on the ecosystem might be an important mechanism accelerating the degradation and desertification of these grasslands.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Aims
Livestock grazing is one of the most common utilization methods and exerts a significant effect on the carbon allocations between the above- and belowground components of a grassland ecosystem. ...The major aim of this study were to evaluate the proportions of
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C allocation to various C pools of the plant-soil system of a meadow steppe ecosystem in response to changes of stocking rate.
Methods
In situ stable
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C isotope pulse labeling was conducted in a long-term grazing experiment with 4 stocking rate. Plant materials and soil samples were taken at eight occasions (0, 3, 10, 18, 31, 56 and 100 days after labeling) to analyze the decline in
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C over time, and their composition signature of
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C were analyzed by the isotope ratio mass spectrometer technique.
Results
We found a significantly greater decline in assimilated
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C of shoot and living root for the heavily grazed swards compared to other stocking rates, with the highest relocation rate of
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C into soil C pool compared to other fractions. In addition, light grazing significantly allocated
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C assimilates in the belowground pool compared to other stocking rates, especially in the live root and topsoil C-pools.
Conclusions
In this study, the effects of grazing on the carbon transfers and stocks within the plant-soil system of the meadow steppe were highly grazing pressure dependent. Plant-soil system in light stocking rate presented the highest C utilization efficiency, however, plants allocated more C to soil C pools with heavily stocking rate.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Dielectric barrier discharge (DBD) plasma applied as surface treatment technology was employed for the modification of Ag2O and graphitic carbon nitride (g-C3N4) powders. Subsequently, the pretreated ...powders were sequentially loaded onto TiO2 nanorods (TiO2-NRs) via electro-deposition, followed by calcination at N2 atmosphere. The results indicated that at the optimal plasma discharge time of 5 min for modification of g-C3N4 and Ag2O, photocurrent density of ternary composite was 6 times to bare TiO2-NRs under UV-visible light irradiation. Phenol was degraded by using DBD plasma-modified g-C3N4/Ag2O/TiO2-NRs electrode to analyze the photoelectrocatalytic performance. The removal rate of phenol for g-C3N4-5/Ag2O-5/TiO2-NRs electrode was about 3.07 times to that for TiO2-NRs electrode. During active species scavengers’ analysis, superoxide radicals and hydroxyl radicals were the main oxidation active species for pollutants degradation. A possible electron-hole separation and transfer mechanism of ternary composite with high photoelectrocatalytic performance was proposed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
Comparing the prediction effects of traditional econometric algorithm model and deep learning algorithm model, taking regional GDP as an example, two prediction models of ARMA-ECM and ...LSTM-SVR are established for prediction, and the prediction results of different models are compared and analyzed. The results show that there are some deviations in the prediction results of the two models, but the prediction trends are the same. The prediction accuracy of LSTM-SVR model will decrease significantly with the reduction of time series data samples, while ARMA-ECM model is not so sensitive.
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