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Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Plateau Meteorology is the property of Plateau Meteorology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil moisture， as a key hydrological variable connecting the surface and atmospheric water and heat exchange， affects the land-air water and heat exchange and carbon cycle process.However， due to the difficulty in monitoring soil moisture in alpine mountain areas， there are some difficulties in related research.The study of time stability can reduce the difficulty of soil moisture acquisition by selecting representative points.In this study， the slope of Shangzhangfanggou grassland in Shiyang River basin of Qilian Mountain was selected to set up a high-density and high-time resolution soil moisture monitoring network to explore the temporal and spatial variation and temporal stability of soil moisture on the slope scale in alpine mountainous areas.The research results show that： （1） The surface soil moisture （10 cm， 15.90%） is significantly higher than that in the deep layer （50 cm， 11.78%）， and its temporal variability （CvT=19.46%） is also stronger than that in the deep layer （CvT=10.67%）， but its spatial variability （CvS=20.05%） is weaker than that in the deep layer （CvS=27.06%）.（2） The time stability Index of Temporal Stability （0.24） is stronger than that of the deep layer （0.34）， and the surface layer and the deep layer can represent the surface soil moisture of the slope through 3 or 5 soil moisture monitoring points respectively （R2> 0.90）.（3） Slope position and soil hydrological properties have obvious influence on time stability， and the time stability point is more likely to appear at the position with larger bulk density and smaller shape parameter n under the slope.The research results are helpful to better understand the temporal and spatial variation law， temporal stability characteristics and control function of soil moisture on slope in alpine mountain areas.

Copyright of Advances in Earth Science (1001-8166) is the property of Advances in Earth Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Sedimentologica Sinica is the property of Acta Sedimentologica Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on soil temperature and humidity and meteorological data at different elevations during the 2020-2021 growing season in the Pailugou watershed of Qilian Mountain， this study analyzed the variation characteristics of soil temperature and humidity and the relationship with meteorological factors， and determined the main meteorological factors affecting soil temperature and humidity.The results showed that： （1） soil temperature tended to increase and then decreased during the growing season （2020）， with a gradual increase in soil temperature from May to August （3.93 ℃） and a decrease from September to October （2.44 ℃）.Meanwhile， soil temperature showed a fluctuating increase with increasing elevation and a gradual decrease with increasing depth of soil layer.（2） Soil moisture showed considerable variation within the growing season， with a general trend of increase and then decrease （2020）， with the lowest soil moisture in May （0.164 m3·m-3） and the highest soil moisture in September （0.318 m3·m-3）.（3） The variation of soil moisture increases with elevation and decreases with the depth of the soil layer.（4） The main meteorological elements affecting soil temperature are air temperature and relative humidity， while soil moisture is mainly affected by air temperature and vapor pressure deficit.

Objective] In order to screen out the most suitable forage species and the best mixed sowing type, to provide scientific basis for ecological restoration of degraded grassland. [Method] The adaptability research of reseeding and mixed sowing of the 9 species of Cleistogenes songorica, Krascheninnikovia ceratoides, Artemisia desertorum, Agriophyllum squarrosum, Haloxylon ammodendron, Seriphidium nitrosum, Kochia prostrata, Sarcozygium xanthoxylon and Melilotus suaveolens in the temperate desert steppe at the northern foot of Qilian Mountains was conducted. The indexes of growth height, coverage and yield of different varieties and different mixed sowing combinations were investigated and recorded. [Result] The results showed that the growth and development performance of Cleistogenes songorica, Artemisia desertorum and Agriophyllum squarrosum were better than other varieties, and the grass yield was higher, were 6 680.5,5 329.5 and 5 259.0 kg/hm², respectively, with strong regional adaptability.Agriophyllum squarrosum + Krascheninnikovia ceratoides + Cleistogenes songorica + Melilotus suaveolens mixture and Cleistogenes songorica+Artemisia desertorum + Krascheninnikovia ceratoides + Seriphidium nitrosum mixture, could significantly increase the yield of grassland, and were the best type of mixed sowing for the restoration in degraded desert grassland. [Conclusion] The adaptability and yield of the Cleistogenes songorica, Artemisia desertorum and Agriophyllum squarrosum were good, so they could be used as the suitable grass species for desert steppe improvement. [ABSTRACT FROM AUTHOR]

Copyright of Plateau Meteorology is the property of Plateau Meteorology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Remote Sensing is the property of Editorial Office of Journal of Remote Sensing & Science Publishing Co. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Prataculturae Sinica is the property of Acta Prataculturae Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Arid Land Geography is the property of Chinese Academy of Sciences, Xinjiang Institute of Ecology & Geography and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper， the ability of CMIP6's 10 global climate models to simulate the historical climate change of Qilian Mountains is tested by using a variety of test parameters.We found that the CESM2-WACCM model has the best simulation effect on projection of climate variation in Qilian Mountains.Therefore， the variation characteristics of temperature， precipitation and humidity in Qilian Mountains from 2020 to 2064 are analyzed under three emission scenarios.They are low， medium and high emission scenario.The results are as follows： （1） In the next half century， the temperature at northern part of Qilian Mountains will be higher， lower at the southern part and higher at both ends， the possibility of heating up is high， the characteristics of warm winter are more obvious than that of warm summer.Comparing the future rise amplitude of Qilian Mountains temperature under different scenarios， it is found that under the high emission scenario， the temperature rises most significantly in winter and summer， while the rise amplitude of medium emission scenario is the lowest.（2） In the future， the precipitation in Qilian Mountains will increase in summer， and the possibility of "humidification" is relatively large.Especially under the scenario of high emission， the intensity of "humidification" is the highest in the eastern part of Qilian Mountains， and it is consistent with the water vapor convergence area shown by the divergence of water vapor flux.（3） The future water vapor variation in Qilian Mountains expressed by atmospheric specific humidity show that atmospheric humidity is more likely to increase in summer， and the variation in southern Qilian Mountains is obvious than that in Northern Qilian Mountains， especially in the scenario of high emission， the East will become more humid in the future， which is consistent with the increase of future precipitation in Qilian Mountains.

The linear regression， Mann-Kendall trend test and Morlet wavelet transform were used to make a detailed analysis on the temporal dynamics and spatial patterns of temperature and precipitation.The temperature and precipitation monitoring data from 12 meteorological stations in the northern slope of Qilian Mountains and its adjacent areas during the period from 1965 to 2018.The results revealed that： （1） The multi-annual mean， maximum and minimum temperatures fluctuated with increase rates of 0.33 ℃·（10a）-1， 0.44 ℃·（10a）-1 and 0.21 ℃·（10a）-1， the temperature changed dramatically in 1998.The multi-annual mean and maximum precipitation fluctuated with increase rates of 4.28 mm·（10a）-1， 16.98 mm·（10a）-1， while the minimum value fluctuated with decrease rates of -4.30 mm·（10a）-1， there was a sudden change in precipitation from less to more in 1971 and 1994.The seasonal variation trend of temperature and precipitation was consistent and continued to rise， and there has a significant increase feature in winter.The interdecadal evolution of the two shows an increasing trend in the 1990s.（2） On the whole， the temperature and precipitation decreased from southeast to northwest， forming a spatial pattern with Zhangye and Gaotai as the dividing line， the temperature and humidity increased faster in the east， and the temperature and humidity increased slower in the west.The overall climate showed a warming and humidity trend.（3） The annual mean temperature has a strong period of 13-year and a period of 6a and 27-year in the scale of 54-year， and there are strong significant periods of 8-year and 20-year and small-scale change periods of 2-year and 27-year.

Precipitation around the Qilian Mountains has close relationship with developing of large-scale circulation system and orographic cloud forced by complex topography in this region.The present work compares synoptic pattern and relevant physical parameters as well as development mechanism of two type precipitation processes around the Qilian Mountains such as CASE1 which occurred during July 19 -20， 2018 and CASE2 which occurred on August 28， 2018 with observed data and high resolution data from WRF model version 3.8.1.Synoptic analyses show that CASE1 precipitation process is the result of interaction between favorable large-scale and local topography， CASE2 is mainly a precipitation process induced by local topography and no significant large-scale circulation system in this process.Results of diagnosis analyses indicate that CASE1 has characteristics such as sufficient water vapor supply， obviously unstable of the stratification， high effective convective energy （1064.84 J·kg-1）， strong vertical shear of the horizontal wind （27.6 m·s-1）， Richardson number （Ri） less than 0 and strong vertical ascending motion et al.before precipitation， which caused the formation of larger area and persistent precipitation process.However， the stratification in CASE2 is more stable than that in CASE1， and the maximum of MCAPE （546.15 J·kg-1） is about half of that in CASE1， the maximum horizontal wind vertical shear （17.37 m·s-1） is far less than that of CASE1， and Richardson number is greater than 0 in the precipitation stage， which means it is a weak convective precipitation process and precipitation rate is relatively smaller as well as and relatively short duration.

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Prataculturae Sinica is the property of Acta Prataculturae Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Plateau Meteorology is the property of Plateau Meteorology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Plateau Meteorology is the property of Plateau Meteorology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of Soil & Water Conservation is the property of Bulletin of Soil & Water Conservation Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Plateau Meteorology is the property of Plateau Meteorology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Grasslands in Qilian Mountains plays an important role in maintaining the ecological security of western China. To understand soil physical and chemical properties and the distribution characteristics of vegetation, as well as their correlation in different types of grasslands in Qilian Mountains, we measured soil moisture, nutrient content, bulk density, particle composition, and vegetation characteristics in seven types of grassland in Qilian Mountains. The fractal dimension of soil particles, soil organic carbon, total nitrogen and total phosphorus storages in 0-40 cm soil layer, and plant diversity index were calculated. The results showed that there were significant differences in soil physical and chemical properties and vegetation characteristics among different grassland types. Compared with other types of grassland, alpine meadow had higher soil water, nutrient and clay content, but lower bulk density and sand content. Soil organic carbon, total nitrogen and total phosphorus storages in 0-40 cm layer ranged from 3084 to 45247, 164 to 2358 and 100 to 319 g· m-2, respectively, with high contents of organic carbon and total nitrogen and low content of total phosphorus. There was a significant positive correlation between soil total phosphorus storage and plant diversity index, indicating that soil total phosphorus content was the key factor affecting grassland plant diversity in Qilian Mountains. Compared with other grassland types, alpine meadow in Qilian Mountains had better vegetation status, soil moisture, and nutrient conditions. [ABSTRACT FROM AUTHOR]

Copyright of Acta Prataculturae Sinica is the property of Acta Prataculturae Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil aggregates reflect the stability of soil structure, soil fertility and quality, and they are closely related to the environmental quality, soil and water loss, and soil erosion. Although vegetation types, soil depths, and altitude likely have important effects on soil properties and soil aggregates, few studies have concentrated on the relationships between their interactive effects and soil aggregate stability on the regional scale. In order to study the variation characteristics of soil aggregates in the Qilian Mountains. In this study, 4 vegetation type zones (desert, steppe, meadow, and shrub) were selected in the Qilian Mountains (northwest China) as the subjects. The stability and size distribution of soil aggregates was measured by the method of wet-sieving. The characteristics of soil aggregate index were analyzed at different soil depths and different altitudes, including the percentage of water-stable aggregate (WSA), mean weight diameter (MWD), geometric mean diameter (GMD), mean weight soil specific area (MWSSA), aggregate processing damage rate ( PAD) and fractal dimension (D). The results showed that the coefficients of variation of soil aggregate index under the 4 vegetation types were high (ranging from 10.91% to 62.50%), which indicated a moderate spatial variability. Among the 4 grassland types, WSA, MWD, GMD and MWSSA all showed the same increased in order: desert < steppe or meadow 30-40 cm depth, no significant differences in aggregate stability index were found among different vegetation types (P>0.05). The reason why the aggregate stability of desert was lowest could be explained by the fact that the lower soil organic carbon (SOC) and biomass of desert, and the small aggregates couldn’t be formed. Along the vertical direction of the soil profiles from aboveground to underground, with the increase of soil depth (0-40 cm), WSA, MWD, GMD, and MWSSA gradually all decreased. Whereas PAD and D behaved opposite to them, and with the increase in soil depth, they gradually increased, which indicated that the stability and aggregation degree of soil aggregates decreased with soil depth. This could be explained as that the SOC appeared enrichment phenomenon in the 0-20 cm layer and decreased with soil depth. The soil aggregate index all tended to be significantly higher in surface layer than in lower layers only at the meadow (P<0.05), but no significant difference in MWSSA (P>0.05) were found among all soil depths. With increasing altitude, the aggregate stability (WSA, MWD, and GMD) increased gradually from 1 692 m, reached a peak at 2 800 m, and then decreased quickly. But the trends were reverse for the PAD and D, and there was no significant correlation between MWSSA and altitude under different vegetation types (P>0.05), which suggested that their distribution clearly showed unimodal patterns across all the altitude. This indicated that the stability and aggregation degree of soil aggregates first increased and then decreased with increasing altitude, and the maximum point appeared at elevation of 2 800 m. In addition, correlation analysis showed that WSA, MWD, and GMD were mainly affected by 1-4 mm, D was mainly affected by 0.038-0.25 mm, and MWSSA couldn't accurately express the characteristics of water-stable aggregates. This research will guide the practice of reducing soil erosion for the different conditions and different vegetation types, and results have great significance for controlling grassland degradation, promoting soil structure stability and the sustainable development of grassland animal husbandry. [ABSTRACT FROM AUTHOR]

Copyright of Acta Prataculturae Sinica is the property of Acta Prataculturae Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Mountain Research (10082786) is the property of Mountain Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Prataculturae Sinica is the property of Acta Prataculturae Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Mountain Research (10082786) is the property of Mountain Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We selected the grid of 5 m × 5 m in a dynamic monitoring plot (340 m × 300 m) as the sampling unites and chose 5 structural characteristics (density, average crown breadth, coverage, conspicuousness and average height) to study the spatial heterogeneity of community structure of Picea crassifolia forest in Dayekou Basin of Qilian Mountains by the fractal geometry and geostatistics methods. The results showed that the order of spatial variation in these characteristics was: density > average crown breadth > conspicuousness > coverage > average height, with the variation coefficient ranging from 43.7% to 79.6%. Moran's I index indicated that the structural variables had different degrees of spatial autocorrelation, and the order of autocorrelation was density > average height> coverage > average crown breadth > conspicuousness, with the range of –0.047–0.382. The exponential semivariation model well fitted the spatial variability in different structural features, and the range was 24.6–68.1 m. The variables displayed moderate spatial autocorrelation except for coverage, while the other variables had strong spatial autocorrelation, and the fractal dimension of the variables was close to 2, indicating a low spatial dependence among variables. The variables presented a superposing characteristic of zonal and patchy structures except for density and coverage, while the other variables presented strong patchiness property. Density and coverage had a certain spatial dependence on average crown breadth, conspicuousness and average height. Density and coverage for the spatial heterogeneity of community structural of P. crassifolia forests were 10 m and 0.5 hm2, respectively. [ABSTRACT FROM AUTHOR]

Qilian Mountains, is an important ecological function area, an important ecological security barrier, the river runoff region in Northwest China, as well as a sensitive area to global climate change and fragile area of ecological environment. The ecological environment in this area played an important role in the economic development of Northwest China. Based on the observation data of temperature and precipitation in Qilian Mountains, MOD10A2 snow products and the flow data of Shiyang River, Heihe River and Shule River, we systematically analyzed the characteristics of climate change from 1961 to 2020, and the impacts of climate change on water resources under the scenario of climate warming. The results showed that, from 1961 to 2020, the annual average temperature increased significantly, with the rate reaching 0.39 ℃·(10 a) -1 . The warming rate was the highest in the western part of Qilian Mountains, followed by the middle and eastern regions. The warming trend was the strongest in winter and the lowest in spring. The average temperature changed abruptly in 1997. The annual average precipitation increased with flucturation, with a rate of 10 mm·(10 a) -1 , which increased most obviously in the middle of Qilian Mountains. After 2004, it entered a rainy period, with a warm and humid trend. The precipitation in the four seasons showed an increasing trend and the increase of precipitation in summer contributed the most to the annual precipitation. Annual precipitation was dominated by interannual scale change, and the contribution rate of 2.8-year was approximately 64.3%. The snow cover of Qilian Mountains was obviously affected by temperature and snowfall, which was negatively correlated with summer temperature and positively correlated with snowfall. From 2016 to 2020, the temperature increase had slowed down in Qilian Mountains, the snowfall had increased, and the snow cover tended to increase. After 2000, the temperature and precipitation increased more obviously, the meltwater from glacier and snow increased, the mountainous runoff of Shiyang River, Heihe River and Shule River had an increasing trend. Our findings are of great significance to the construction of ecological civilization and coping with climate change in Qilian Mountains.

This paper estimated the biomass and carbon storage and their spatial distributions of Qinghai spruce (Picea crassifolia) forests in Qilian Mountains, based on the field investigation, forest map, and meteorological data, and with the help of GIS technology. In 2008, the biomass of the forests was averagely 209.24 t·hm-2, with a total biomass of 3.4×107 t. Due to the difference of water and thermal condition, there existed great differences in the biomass of Qinghai spruce within the Mountains. The biomass increased by 3.12 t· hm-2 with increasing 1-longitude and decreased by 3.8 t· hm-2 with increasing 1º latitude, and decreased by 0.05 t· hm-2 with the elevation increasing 100 m. The carbon density of the forests ranged from 70.4 to 131.1 t· hm-2, averagely 109.8 t · hm-2, and the average carbon density was 83.8 t · hm-2 for the young forest, 109.6 t· hm-2 for the middle age forest, 122 t· hm-2 for the near-mature forest, 124.2 t· hm-2 for the mature forest, and 117.1 t· hm-2 for the over-mature forest. The total carbon storage of Qinghai spruce forests in the study area was 1.8×107 t. [ABSTRACT FROM AUTHOR]

This paper studied the distribution patterns of organic carbon (OC), total nitrogen (TN), NH4+-N, and NO3--N in the profiles of brown calcic soil, grey cinnamon soil, chestnut soil, and alpine meadow soil in the middle of Qilian Mountains. In all test soils, the contents of OC, TN, NH4+-N, and NO3--N decreased with increasing soil depth, and the accumulation and decomposition of OC and various N forms differed with soil types. The average content of OC in different soil profiles changed from 14.01 to 41.17 g·kg-1, and was in the order of grey cinnamon soil > alpine meadow soil > chestnut soil > brown calcic soil; the average content of TN changed from 1.28 to 2.73 g·kg-1, with a sequence of alpine meadow soil > grey cinnamon soil > chestnut soil > brown calcic soil. The C/N ratio was from 11.33 to 19.22, with the order of grey cinnamon soil > chestnut soil > alpine meadow soil > brown calcic soil. NH4+-N content changed from 5.80 to 8.40 mg·kg-1, and was in the order of brown calcic soil > alpine meadow soil > chestnut soil > grey cinnamon soil; NO3--N content changed from 6.57 to 15.11 mg·kg-1, being in the order of chestnut soil > alpine meadow soil > brown calcic soil > grey cinnamon soil. The ratio of NO3--N to NH4+-N was 1.00-2.69, with the sequence of grey cinnamon soil > chestnut soil > alpine meadow soil > brown calcic soil. The OC and N contents in the same soil types differed significantly with the conditions of climate, vegetation, and topography (e.g., slope aspect and slope position). Correlation analysis showed that there were highly significant positive correlations between OC, TN, and NH4+-N, but these three items had no significant positive correlations with NO3--N. Furthermore, there were highly significant positive correlations between available K, NH4+-N, and NO3--N and between available P and OC, significant positive correlations between available P, TN, and NH4+-N, but no significant correlations between pH, total K, and total P and OC and N. [ABSTRACT FROM AUTHOR]

With the shady and sunny northern slopes of Qilian Mountains along an altitude gradient from 2600 m to 3600 m as test objectives, this paper studied t he vertical distribution patterns of surface soil (0-20 cm) organic carbon (SOC) and total nitrogen (TN), and their relations to the altitude, landform, and vegetation. The results indicated that SOC and TN contents were significantly higher on shady than on sunny slope, and all increased with increasing altitude. The SOC and TN contents under different vegetation types were in the order of alpine bush > Picea crassifolia forest > alpine meadow > Sabina przewalskii forest, and alpine bush > alpine meadow > P. crassifolia forest > S. przewalskii forest, respectively. SOC had significant positive correlations with altitude, annual precipitation, soil moisture, and soil TN, and significant negative correlations with soil pH and annual temperature. Soil C/N ratio along the gradient was within the range of 6.7-23.3, being favorable to the nutrient release during organic matter decomposition. Among the factors affecting SOC, the annual temperature, precipitation, and soil moisture content constituted the first principal component, and soil C/N ratio constituted the second principal component . These two principal components accounted for 71% of the variance of SOC content, suggesting that climate factors controlled the vertical distribution patterns of SOC and TN along the altitude gradient. [ABSTRACT FROM AUTHOR]

Grasslands in Qilian Mountains plays an important role in maintaining the ecological security of western China. To understand soil physical and chemical properties and the distribution characteristics of vegetation, as well as their correlation in different types of grasslands in Qilian Mountains, we measured soil moisture, nutrient content, bulk density, particle composition, and vegetation characteristics in seven types of grassland in Qilian Mountains. The fractal dimension of soil particles, soil organic carbon, total nitrogen and total phosphorus storages in 0-40 cm soil layer, and plant diversity index were calculated. The results showed that there were significant differences in soil physical and chemical properties and vegetation characteristics among different grassland types. Compared with other types of grassland, alpine meadow had higher soil water, nutrient and clay content, but lower bulk density and sand content. Soil organic carbon, total nitrogen and total phosphorus storages in 0-40 cm layer ranged from 3084 to 45247, 164 to 2358 and 100 to 319 g·m -2 , respectively, with high contents of organic carbon and total nitrogen and low content of total phosphorus. There was a significant positive correlation between soil total phosphorus storage and plant diversity index, indicating that soil total phosphorus content was the key factor affec-ting grassland plant diversity in Qilian Mountains. Compared with other grassland types, alpine meadow in Qilian Mountains had better vegetation status, soil moisture, and nutrient conditions.

Tree-rings of Picea crassifolia from high (3000 m), middle (2750 m) and low (2500 m) altitudes were collected from the Xiying River basin in the eastern Qilian Mountains, with the standard chronology being established using dendrochronological methods. Results of the correlation analysis between tree-ring width index and temperature and precipitation during different periods showed that radial growth of P. crassifolia at different altitudes responded differently to climate warming in the eastern Qilian Mountains. Water and heat availability were the main limiting factors for the radial growth of P. crassifolia in the eastern part of Qilian Mountains. The growth limiting factors at different altitudes were generally the same. Before the prominent warming (1961-1986), radial growth of P. crassifolia at the three sampling altitudes was significantly negatively correlated with mean maximum temperature in July-August of the previous year and August of the current year, and significantly positively correlated with the relative humidity in June of the current year. After the prominent warming period (1986-2014), tree growth at high, middle, and low altitudes remained significantly negatively correlated with air temperature, changed from non-significantly negative to significantly positive correlation with relative humidity in February of the current year, and changed from significantly positive to non-significantly negative correlation with precipitation and relative humidity in June. Warming caused a slowing growth of P. crassifolia tree-ring at all altitudes, with the highest altitude being the most sensitive. Drought stress caused by climate warming might be the main reason for the changes of radial growth of P. crassifolia .

Foliar stoichiometry provides information on the biotic and abiotic changes of environment. We examined the stoichiometric characteristics of plant leaves at different altitudes to understand how plants adapt to environmental changes. Foliar stoichiometry of Leontopodium leontopodioides at various altitudes (2400, 2600, 2800, 3000 and 3200 m) were analyzed in the Qilian Mountains of China. Across the altitude gradient, mean value of leaf carbon content (LC), nitrogen content (LN), and phosphorous content (LP) of L. leontopodioides was 401.27, 23.99 and 1.22 g·kg -1 , respectively. The mean value of LC:LN, LC:LP and LN:LP was 16.8, 352.5 and 20.7, respectively. LC, LC:LN, LC:LP and LN:LP initially increased with increases in altitude, rea-ching the maximum at 2600 m, then decreased, reaching the minimum at 3000 m, and finally increased again. LP exhibited the opposite trend. LN demonstrated an initial decrease with altitude, reaching the minimum at 2800 m, followed by an increase at higher altitudes. LC did not correlate with LN, but was significantly negatively correlated with LP. LN was significantly positively correlated with LP. There was no correlation between LN and any other stoichiometry ratios. LP showed a significantly negative correlation with other stoichiometry ratios. LC:LN, LC:LP, and LN:LP were positively correlated with each other. Both soil total nitrogen and total phosphorus affected LC and LN, whereas LP was significantly negatively correlated with soil total phosphorus. The results suggested that the growth of L. leontopodioides in the study region was mainly limited by P availability.

Precipitation of the northwest China is different from that in other regions of China. The vapor reaches this region after long distance transportation with little precipitation, and the ratio of precipitation variation is large. Wushaoling at the east Qilian Mountains is an important divided line of climate in China. The east region of it is affected by South Asia and East Asia monsoon, while the west region of it is influenced by Westerly circulation. So ion combinations in precipitation are complex for the trajectories of water vapor transportation, the natural environments and the development levels of social and economy in different regions. Precipitation samples were collected at Heisongyi located at the east Qilian Mountains. Hydrochemical characteristics and sources of ions were analyzed by factor analysis, Enrichment factor analysis and back trajectory analysis. EC values in precipitation ranged from 29.20 to 892.00 μS·cm -1 , which were controlled by alkaline element. The precipitation was weak alkaline with pH values ranging from 7.02 to 8.89. EC values in precipitation were higher in autumn and winter than in spring and summer, opposite to pH values. The type of precipitation was SO 4 2- -Ca 2+ for the cation concentrations following the order of Ca 2+ >Mg 2+ >Na + >NH 4 + >K + and the anion concentrations following the order of SO 4 2- >Cl - >NO 3 - . The concentrations of K + , Mg 2+ , Ca 2+ , NH 4 + , Cl - , NO 3 - and SO 4 2- were the highest in autumn, but the peak value of Na + concentration appeared in winter. As a whole, ion concentrations were higher in autumn and winter than in spring and summer. Enrichment factor indicated that Na + and Cl - mainly came from marine source but Na + partly originated from crust source in winter and Cl - partly originated from anthropogenic source in winter, and that K + , Mg 2+ and Ca 2+ mainly came from crust source except that Mg 2+ partly originated from anthropogenic source in winter, and that NO 3 - and SO 4 2- mainly came from anthropogenic source. The trajectories of water vapor transportation from directions of northwest, north, north with southeast, northwest with southeast, northwest with southwest, northwest with north and southeast were ion original sources in precipitation, and the major trajectory came from northwest direction. Among these trajectories of water vapor transportation, that from northwest, north and north with southeast appeared in each season, but that from northwest with southeast appeared in spring and summer, that from northwest with southwest and northwest and north with southeast appeared in summer. Though ions originated from marine transport by Westerly and monsoon, from crust provided by desert and Gobi in central Asia, Xingjiang and Mongolian plateau, and from humanity activity related to cities pollution and industrial and agriculture production of oasis at all trajectories, the concentrations of ions in precipitation were effected by the strong and weak variations of different weather systems.