Effects of short-term and long-term warming on soil nutrients, microbial biomass and enzyme activities in an alpine meadow on the Qinghai-Tibet Plateau of China

2014 ◽  
Vol 76 ◽  
pp. 140-142 ◽  
Author(s):  
Xuexia Wang ◽  
Shikui Dong ◽  
Qingzhu Gao ◽  
Huakun Zhou ◽  
Shiliang Liu ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Nutrients ◽  
Enzyme Activities ◽  
Alpine Meadow ◽  
Tibet Plateau ◽  
Short Term ◽  
Qinghai Tibet Plateau

scholarly journals Nitrogen retention patterns and their controlling factors in an alpine meadow: implications for carbon sequestration

2007 ◽  
Vol 4 (4) ◽  
pp. 2641-2665 ◽  
Author(s):  
X. L. Xu ◽  
H. Ouyang ◽  
G. M. Cao
Keyword(s):  
Alpine Meadow ◽  
Nitrogen Retention ◽  
Tibet Plateau ◽  
Short Term ◽  
Organic Carbon Concentration ◽  
Long Term Retention ◽  
Abiotic And Biotic Factors ◽  
One Year ◽  
Qinghai Tibet Plateau

Abstract. We hypothesized that the patterns of NO3− and NH4+ retention are different over short-term scales while they are similar over long-term scales in alpine meadows and that abiotic and biotic factors might be responsible for their different patterns over short-term scales. In order to test the hypotheses, a 15N-labeled experiment was conducted in an alpine meadow in the Qinghai-Tibet Plateau over four years. Our results showed that 15NO3− and 15NH4+ retention was distinctly different within two months, and even one year after tracer additions. The long-term retention of 15N at the whole-plot level did not differ significantly between 15NH4+ and 15NO3− treatments, and averaged 50% after four years. Higher soil temperature or soil organic carbon concentration enhanced 15NH4+ retention, but significantly reduced 15NO3− retention in the soil within two months following tracer additions. Soil moisture significantly affected 15N recovered in soil organic matter and microbial biomass as well as aboveground parts, but had no significant effects on 15N recovered in roots. These findings have important ecological implications with regard to the consequences of deposited nitrogen because of the possible difference in the fate of NH4+ vs. NO3− in alpine meadow ecosystems.

scholarly journals Vegetation degradation impacts soil nutrients and enzyme activities in wet meadow on the Qinghai-Tibet Plateau

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jiangqi Wu ◽  
Haiyan Wang ◽  
Guang Li ◽  
Weiwei Ma ◽  
Jianghua Wu ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Soil Nutrients ◽  
Enzyme Activities ◽  
Soil Depth ◽  
Soil Nutrient ◽  
Tibet Plateau ◽  
Wet Meadow ◽  
Vegetation Degradation ◽  
Thaw Cycle ◽  
Qinghai Tibet Plateau

AbstractVegetation degradation, due to climate change and human activities, changes the biomass, vegetation species composition, and soil nutrient input sources and thus affects soil nutrient cycling and enzyme activities. However, few studies have focused on the responses of soil nutrients and enzymes to vegetation degradation in high-altitude wet meadows. In this study, we examined the effects of vegetation degradation on soil nutrients (soil organic carbon, SOC; total nitrogen, TN; total phosphorus, TP) and enzyme activities (i.e., urease, catalase, amylase) in an alpine meadow in the eastern margin of the Qinghai-Tibet Plateau. Four different levels of degradation were defined in terms of vegetation density and composition: primary wet meadow (CK), lightly degraded (LD), moderately degraded (MD), and heavily degraded (HD). Soil samples were collected at depth intervals of 0–10, 10–20, 20–40, 40–60, 60–80, and 80–100 cm to determine soil nutrient levels and enzyme activities. The results showed that SOC, TN, catalase and amylase significantly decreased with degradation level, while TP and urease increased with degradation level (P < 0.05). Soil nutrient and enzyme activity significantly decreased with soil depth (P < 0.05), and the soil nutrient and enzyme activity exhibited obvious "surface aggregation". The activities of soil urease and catalase were strongest in spring and weakest in winter. The content of TN in spring, summer, and autumn was significantly higher than observed in winter (P < 0.05). The soil TP content increased in winter. Soil amylase activity was significantly higher in summerm than in spring, autumn, and winter (P < 0.05). TP was the main limiting factor for plant growth in the Gahai wet meadow. Values of SOC and TN were positively and significantly correlated with amylase and catalase (P < 0.05), but negatively correlated with urease (P < 0.05). These results suggest the significant role that vegetation degradation and seasonal freeze–thaw cycle play in regulating enzyme activities and nutrient availability in wet meadow soil.

scholarly journals Seasonal and interannual dynamics of soil microbial biomass and available nitrogen in an alpine meadow in the eastern part of Qinghai–Tibet Plateau, China

2018 ◽  
Vol 15 (2) ◽  
pp. 567-579 ◽  
Author(s):  
Bo Xu ◽  
Jinniu Wang ◽  
Ning Wu ◽  
Yan Wu ◽  
Fusun Shi
Keyword(s):  
Microbial Biomass ◽  
Alpine Meadow ◽  
Nutrient Supply ◽  
Tibet Plateau ◽  
Available N ◽  
Soil Microbial ◽  
Seasonal And Interannual Dynamics ◽  
Interannual Dynamics ◽  
Qinghai Tibet Plateau ◽  
N Pool

Abstract. Soil microbial activity varies seasonally in frozen alpine soils during cold seasons and plays a crucial role in available N pool accumulation in soil. The intra- and interannual patterns of microbial and nutrient dynamics reflect the influences of changing weather factors, and thus provide important insights into the biogeochemical cycles and ecological functions of ecosystems. We documented the seasonal and interannual dynamics of soil microbial and available N in an alpine meadow in the eastern part of Qinghai–Tibet Plateau, China, between April 2011 and October 2013. Soil was collected in the middle of each month and analyzed for water content, microbial biomass C (MBC) and N (MBN), dissolved organic C and N, and inorganic N. Soil microbial community composition was measured by the dilution-plate method. Fungi and actinomycetes dominated the microbial community during the nongrowing seasons, and the proportion of bacteria increased considerably during the early growing seasons. Trends of consistently increasing MBC and available N pools were observed during the nongrowing seasons. MBC sharply declined during soil thaw and was accompanied by a peak in available N pool. Induced by changes in soil temperatures, significant shifts in the structures and functions of microbial communities were observed during the winter–spring transition and largely contributed to microbial reduction. The divergent seasonal dynamics of different N forms showed a complementary nutrient supply pattern during the growing season. Similarities between the interannual dynamics of microbial biomass and available N pools were observed, and soil temperature and water conditions were the primary environmental factors driving interannual fluctuations. Owing to the changes in climate, seasonal soil microbial activities and nutrient supply patterns are expected to change further, and these changes may have crucial implications for the productivity and biodiversity of alpine ecosystems.

Long-term grazing exclusion greatly improve carbon and nitrogen store in an alpine meadow on the northern Qinghai-Tibet Plateau

CATENA ◽  
2021 ◽  
Vol 197 ◽  
pp. 104955
Author(s):  
Licong Dai ◽  
Ruiyu Fu ◽  
Xiaowei Guo ◽  
Yangong Du ◽  
Li Lin ◽  
...  
Keyword(s):  
Alpine Meadow ◽  
Tibet Plateau ◽  
Carbon And Nitrogen ◽  
Grazing Exclusion ◽  
Qinghai Tibet Plateau

scholarly journals Distinguishing Stoichiometric Homeostasis of Soil Microbial Biomass in Alpine Grassland Ecosystems: Evidence From 5,000 km Belt Transect Across Qinghai–Tibet Plateau

2021 ◽  
Vol 12 ◽  
Author(s):  
Jihui Fan ◽  
Tianyuan Liu ◽  
Ying Liao ◽  
Yiying Li ◽  
Yan Yan ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Alpine Meadow ◽  
Alpine Grassland ◽  
Tibet Plateau ◽  
Trade Off ◽  
Soil C ◽  
Soil Microbial ◽  
Alpine Steppe ◽  
Qinghai Tibet Plateau

The biogeographic characteristics of soil microbial biomass stoichiometry homeostasis and also its mechanisms are commonly thought to be key factors for the survival strategies and resource utilization of soil microbes under extreme habitat. In this work, we conducted a 5,000-km transect filed survey in alpine grassland across Qinghai–Tibet Plateau in 2015 to measure soil microbial biomass carbon (MBC) and nitrogen (MBN) across alpine steppe and meadow. Based on the differences of climate and soil conditions between alpine steppe and meadow, the variation coefficient was calculated to investigate the homeostatic degree of MBC to MBN. Furthermore, the “trade-off” model was utilized to deeply distinguish the homeostasis degree of MBC/MBN between alpine steppe and meadow, and the regression analysis was used to explore the variability of trade-off in response to environmental factors in the alpine grassland. The results showed that the coefficient of variation (CV) of MBC/MBN in alpine meadow (CV = 0.4) was lower than alpine steppe (CV = 0.7). According to the trade-off model, microbial turnover activity of soil N relative to soil C increased rapidly and then decreased slightly with soil organic carbon (SOC), soil total nitrogen (STN), and soil water content across alpine meadow. Nevertheless, in alpine steppe, SOC/STN had a positive effect on microbial turnover of soil N. These results suggested that water, heat, and soil nutrients availability were the key factors affecting the C:N stoichiometry homeostasis of soil microbial biomass in Qinghai–Tibet Plateau (QTP)’s alpine grassland. Since the difference of survival strategy of the trade-off demands between soil C and N resulting in different patterns and mechanism, the stoichiometry homeostasis of soil microbial biomass was more stable in alpine meadow than in alpine steppe.

scholarly journals Spatial and Temporal Differences in Alpine Meadow, Alpine Steppe and All Vegetation of the Qinghai-Tibetan Plateau and Their Responses to Climate Change

2021 ◽  
Vol 13 (4) ◽  
pp. 669
Author(s):  
Hanchen Duan ◽  
Xian Xue ◽  
Tao Wang ◽  
Wenping Kang ◽  
Jie Liao ◽  
...  
Keyword(s):  
Climate Change ◽  
Alpine Meadow ◽  
Global Climate ◽  
Growing Season ◽  
Tibet Plateau ◽  
Vegetation Types ◽  
Analysis Method ◽  
Alpine Steppe ◽  
Qinghai Tibet Plateau ◽  
Variation Trends

Alpine meadow and alpine steppe are the two most widely distributed nonzonal vegetation types in the Qinghai-Tibet Plateau. In the context of global climate change, the differences in spatial-temporal variation trends and their responses to climate change are discussed. It is of great significance to reveal the response of the Qinghai-Tibet Plateau to global climate change and the construction of ecological security barriers. This study takes alpine meadow, alpine steppe and the overall vegetation of the Qinghai-Tibet Plateau as the research objects. The normalized difference vegetation index (NDVI) data and meteorological data were used as the data sources between 2000 and 2018. By using the mean value method, threshold method, trend analysis method and correlation analysis method, the spatial and temporal variation trends in the alpine meadow, alpine steppe and the overall vegetation of the Qinghai-Tibet Plateau were compared and analyzed, and their differences in the responses to climate change were discussed. The results showed the following: (1) The growing season length of alpine meadow was 145~289 d, while that of alpine steppe and the overall vegetation of the Qinghai-Tibet Plateau was 161~273 d, and their growing season lengths were significantly shorter than that of alpine meadow. (2) The annual variation trends of the growing season NDVI for the alpine meadow, alpine steppe and the overall vegetation of the Qinghai-Tibet Plateau increased obviously, but their fluctuation range and change rate were significantly different. (3) The overall vegetation improvement in the Qinghai-Tibet Plateau was primarily dominated by alpine steppe and alpine meadow, while the degradation was primarily dominated by alpine meadow. (4) The responses between the growing season NDVI and climatic factors in the alpine meadow, alpine steppe and the overall vegetation of the Qinghai-Tibet Plateau had great spatial heterogeneity in the Qinghai-Tibet Plateau. These findings provide evidence towards understanding the characteristics of the different vegetation types in the Qinghai-Tibet Plateau and their spatial differences in response to climate change.

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