Accurate estimate of soil carbon storage is essential to reveal the role of soil in global carbon cycle. However, there is large uncertainty on the estimation of soil organic carbon(SOC) storage in grassland among pre...Accurate estimate of soil carbon storage is essential to reveal the role of soil in global carbon cycle. However, there is large uncertainty on the estimation of soil organic carbon(SOC) storage in grassland among previous studies, and the study on soil inorganic carbon(SIC) is still lack. We surveyed 153 sites during plant peak growing season and estimated SOC and SIC for temperate desert, temperate steppe, alpine steppe, steppe meadow, alpine meadow and swamp, which covered main grassland in the Qinghai Plateau during 2011 to 2012. The results showed that the vertical and spatial distributions of SOC and SIC varied by grassland types. The SOC amount mainly decreased from southeast to northwest, whereas the SIC amount increased from southeast to northwest. The magnitude of SOC amount in the top 50 cm across grassland types ranked by: swamp > alpine meadow >steppe meadow > temperate steppe > alpine steppe > temperate desert, while the SIC amount showed an opposite order. There was a great deal of variation in proportion of SOC and SIC among different grassland types(from 55.17 to 94.59 for SOC and 5.14 to 44.83 for SIC). The total SOC and SIC storage was 5.78 Pg and 1.37 Pg, respectively, in the top 50 cm of soil in Qinghai Province. The mixed linear model revealed that grassland types was the predominant factor in spatial variations of SOC amount while grassland types and soil p H accounted for those of SIC amount. Our results suggested that the community shift of alpine meadow towards alpine grassland induced by climate warming would decrease carbon sequestration capacity by 6.0 kg C m2.展开更多
Litter decomposition is an important component of the nutrient recycling process and is highly sensitive to climate change.However,the impacts of warming and increased precipitation on litter decomposition have not be...Litter decomposition is an important component of the nutrient recycling process and is highly sensitive to climate change.However,the impacts of warming and increased precipitation on litter decomposition have not been well studied,especially in the alpine grassland of Tianshan Mountains.We conducted a manipulative warming and increased precipitation experiment combined with different grassland types to examine the impact of litter quality and climate change on the litter decomposition rate based on three dominant species(Astragalus mongholicus,Potentilla anserina,and Festuca ovina)in Tianshan Mountains from 2019 to 2021.The results of this study indicated there were significant differences in litter quality,specific leaf area,and leaf dry matter content.In addition,litter quality exerted significant effects on litter decomposition,and the litter decomposition rate varied in different grassland types.Increased precipitation significantly accelerated the litter decomposition of P.anserina;however,it had no significant effect on the litter decomposition of A.mongholicus and F.ovina.However,warming consistently decreased the litter decomposition rate,with the strongest impact on the litter decomposition of F.ovina.There was a significant interaction between increased precipitation and litter type,but there was no significant interaction between warming and litter type.These results indicated that warming and increased precipitation significantly influenced litter decomposition;however,the strength was dependent on litter quality.In addition,soil water content played a crucial role in regulating litter decomposition in different grassland types.Moreover,we found that the litter decomposition rate exhibited a hump-shaped or linear response to the increase of soil water content.Our study emphasizes that ongoing climate change significantly altered litter decomposition in the alpine grassland,which is of great significance for understanding the nutrient supply and turnover of litter.展开更多
Soil organic carbon(SOC) and soil total nitrogen(STN) in arid regions are important components of global C and the N cycles, and their response to climate change will have important implications for both ecosystem pro...Soil organic carbon(SOC) and soil total nitrogen(STN) in arid regions are important components of global C and the N cycles, and their response to climate change will have important implications for both ecosystem processes and global climate feedbacks. Grassland ecosystems of Funyun County in the southern foot of the Altay Mountains are characterized by complex topography, suggesting large variability in the spatial distribution of SOC and STN. However, there has been little investigation of SOC and STN on grasslands in arid regions with a mountain-basin structure. Therefore, we investigated the characteristics of SOC and STN in different grassland types in a mountain-basin system at the southern foot of the Altai Mountains, north of the Junggar Basin in China, and explored their potential influencing factors and relationships with meteorological factors and soil properties. We found that the concentrations and storages of SOC and STN varied significantly with grassland type, and showed a decreasing trend along a decreasing elevation gradient in alpine meadow, mountain meadow, temperate typical steppe, temperate steppe desert, and temperate steppe desert. In addition, the SOC and STN concentrations decreased with depth, except in the temperate desert steppe. According to Pearson's correlation values and redundancy analysis, the mean annual precipitation, soil moisture content and soil available N concentration were significantly positively correlated with the SOC and STN concentrations. In contrast, the mean annual temperature, p H, and soil bulk density were significantly and negatively correlated with the SOC and STN concentrations. The mean annual precipitation and mean annual temperature were the primary factors related to the SOC and STN concentrations. The distributions of the SOC and STN concentrations were highly regulated by the elevation-induced differences in meteorological factors. Mean annual precipitation and mean annual temperature together explained 97.85% and 98.38% of the overall variations in the SOC and STN concentrations, respectively, at soil depth of 0–40 cm, with precipitation making the greatest contribution. Our results provide a basis for estimating and predicting SOC and STN concentrations in grasslands in arid regions with a mountain-basin structure.展开更多
Owing to the joint effects of ecosystem fragility,anthropogenic disturbance and climate change,alpine grasslands(alpine meadow,alpine steppe and alpine desert)have experienced serious degradation during the past sever...Owing to the joint effects of ecosystem fragility,anthropogenic disturbance and climate change,alpine grasslands(alpine meadow,alpine steppe and alpine desert)have experienced serious degradation during the past several decades.Grasslands degradation has severely affected the delivery of ecosystem multifunctionality(EMF)and services,and then threatens the livelihood of local herdsmen and ecological security of China.However,we still lack comprehensive insights about the effects of degradation and climatic factors on EMF of alpine grasslands,especially for alpine desert ecosystem.Therefore,we applied a large-scale field investigation to answer this question.Our results suggested grassland degradation significantly decreased the belowground ecosystem multifunctionality(BEMF)and EMF of alpine grasslands and aboveground ecosystem multifunctionality(AEMF)of alpine meadow,while did not reduce the AEMF of alpine steppe and desert.Except for the insignificant difference between degraded steppe and degraded desert in AEMF,the alpine meadow showed the highest AEMF,BEMF and EMF,alpine steppe ranked the second and alpine desert was the lowest.AEMF,BEMF and EMF of health alpine grasslands were strongly affected by mean annual precipitation(MAP)(19%-51%)and mean annual temperature(MAT)(9%-36%),while those of degraded meadow and degraded desert were not impacted by precipitation and temperature.AEMF and BEMF showed a synergistic relationship in healthy alpine grasslands(12%-28%),but not in degraded grasslands.Our findings emphasized the urgency of implementing the feasible ecological restoration project to mitigate the negative influences of grassland degradation on EMF of alpine ecosystems.展开更多
Grazing is a main human activity in the grasslands of Xinjiang, China. It is vital to identify the effects of grazing on the sustainable utilization of local grasslands. However, the effects of grazing on net primary ...Grazing is a main human activity in the grasslands of Xinjiang, China. It is vital to identify the effects of grazing on the sustainable utilization of local grasslands. However, the effects of grazing on net primary productivity(NPP), evapotranspiration(ET) and water use efficiency(WUE) in this region remain unclear. Using the spatial Biome-BGC grazing model, we explored the effects of grazing on NPP, ET and WUE across the different regions and grassland types in Xinjiang during 1979–2012. NPP, ET and WUE under the grazed scenario were generally lower than those under the ungrazed scenario, and the differences showed increasing trends over time. The decreases in NPP, ET and WUE varied significantly among the regions and grassland types. NPP decreased as follows: among the regions, Northern Xinjiang(16.60 g C/(m^2·a)), Tianshan Mountains(15.94 g C/(m^2·a)) and Southern Xinjiang(-3.54 g C/(m^2·a)); and among the grassland types, typical grasslands(25.70 g C/(m^2·a)), swamp meadows(25.26 g C/(m^2·a)), mid-mountain meadows(23.39 g C/(m^2·a)), alpine meadows(6.33 g C/(m^2·a)), desert grasslands(5.82 g C/(m^2·a)) and saline meadows(2.90 g C/(m^2·a)). ET decreased as follows: among the regions, Tianshan Mountains(28.95 mm/a), Northern Xinjiang(8.11 mm/a) and Southern Xinjiang(7.57 mm/a); and among the grassland types, mid-mountain meadows(29.30 mm/a), swamp meadows(25.07 mm/a), typical grasslands(24.56 mm/a), alpine meadows(20.69 mm/a), desert grasslands(11.06 mm/a) and saline meadows(3.44 mm/a). WUE decreased as follows: among the regions, Northern Xinjiang(0.053 g C/kg H_2O), Tianshan Mountains(0.034 g C/kg H_2O) and Southern Xinjiang(0.012 g C/kg H_2O); and among the grassland types, typical grasslands(0.0609 g C/kg H_2O), swamp meadows(0.0548 g C/kg H_2O), mid-mountain meadows(0.0501 g C/kg H_2O), desert grasslands(0.0172 g C/kg H_2O), alpine meadows(0.0121 g C/kg H_2O) and saline meadows(0.0067 g C/kg H_2O). In general, the decreases in NPP and WUE were more significant in the regions with relatively high levels of vegetation growth because of the high grazing intensity in these regions. The decreases in ET were significant in mountainous areas due to the terrain and high grazing intensity.展开更多
This research classified vegetation types and evaluated net primary productivity(NPP) of southern China's grasslands based on the improved comprehensive and sequential classification system(CSCS), and proposed 5 t...This research classified vegetation types and evaluated net primary productivity(NPP) of southern China's grasslands based on the improved comprehensive and sequential classification system(CSCS), and proposed 5 thermal grades and 6 humidity grades. Four classes of grasslands vegetation were recognized by improved CSCS, namely, tundra grassland class, typical grassland class, mixed grassland class and alpine grassland class. At the type level, 14 types of vegetations(9 grasslands and 5 forests) were classified. The NPP had a trend to decrease from east to west and south to north, and the annual mean NPP was estimated to be 656.3 g C m-2 yr-1. The NPP value of alpine grassland class was relatively high, generally more than 1 200 g C m-2 yr-1. The NPP value of mixed grassland class was in a range from 1 000 to 1 200 g C m-2 yr-1. Tundra grassland class was located in southeastern Tibet with high elevation, and its NPP value was the lowest(<600 g C m-2 yr-1). The typical grassland class distributed in most of the area, and its NPP value was generally from 600 to 1 000 g C m-2 yr-1. The total NPP value in the study area was 68.46 Tg C. The NPP value of typical grassland class was the highest(48.44 Tg C), and mixed grassland class was the second(16.54 Tg C), followed by alpine grassland class(3.22 Tg C), with tundra grassland class being the lowest(0.25 Tg C). For all the grasslands types, the total NPP of forest meadow was the highest(34.81 Tg C), followed by sparse forest brush(16.54 Tg C), and montane meadow was the lowest(0.01 Tg C).展开更多
The purpose of the present study was to survey contents of trace elements of Cu,Mn,Fe,and Zn in the surface layer(0-20 cm) in the soil,pasture and serum of sheep in Huangcheng area of Qilian mountain grassland,China.A...The purpose of the present study was to survey contents of trace elements of Cu,Mn,Fe,and Zn in the surface layer(0-20 cm) in the soil,pasture and serum of sheep in Huangcheng area of Qilian mountain grassland,China.Also the soil-plantanimal continuum was analyzed.Soil(n=300),pasture(n=60),and blood serum samples from sheep(n=480) were collected from Huangcheng area of Qilian mountain grassland,China.The contents of trace element in the samples were analyzed by atomic absorption spectrophotometer after digestion.The soil trace elements density distribution shows a ladder-like pattern distribution.Equations developed in the present study for prediction of Fe(R2=0.943) and Zn(R2=0.882) had significant R2 values.展开更多
Land use change significantly influences soil properties.There is little information available on the long-term effects of post-reclamation from grassland to cropland on soil properties.We compared soil carbon(C) and ...Land use change significantly influences soil properties.There is little information available on the long-term effects of post-reclamation from grassland to cropland on soil properties.We compared soil carbon(C) and nitrogen(N) storage and related soil properties in a 50-year cultivation chronosequence of grassland in the agro-pastoral ecotone of Inner Mongolia.Field surveys on land use changes during the period of 1955-2002 were conducted to build a chronosequence of cropland of different ages since the conversion from grassland.The results showed that soil C and N storage,soil texture,and soil nutrient contents varied with land use types and cropland ages(P<0.01).In the 0-30 cm soil layer,the soil organic carbon(SOC) density was significantly lower in the croplands(3.28 kg C/m2 for C50 soil) than in the grasslands(6.32 kg C/m2).After 5,10,15,20,35,and 50 years of crop planting(years since the onset of cultivation),the SOC losses were 17%,12%,19%,47%,46%,and 48%,respectively,compared with the grasslands.The soil total nitrogen(TN) density of the grasslands was 65 g N/m2,and TN density of the cropland soil was 35 g N/m2 after 50 years of crop planting.Both the SOC and TN densities could be quantitatively determined by a negative exponential function of cropland age(P<0.0001,R2=0.8528;P<0.0001,R2=0.9637).The dissolved organic carbon(DOC) content,soil available potassium(AK) content,clay content,and pH value were decreased;and the soil bulk density and sand content were increased since the conversion of grassland into cropland during the 50-year period.Our results show soil nutrients were higher in grassland than in cropland.The conversion of grasslands to croplands induced a loss of soil C storage and changes of related soil properties.The reclamation time of cultivated soil(cropland age) had significant effects on soil properties in the study area.展开更多
基金supported by the“Natural Science Foundation of China(41030105)"“Strategic Priority Research Program-Climate Change:Carbon Budget and Related Issues”of the Chinese Academy of Sciences(XDA05050404)
文摘Accurate estimate of soil carbon storage is essential to reveal the role of soil in global carbon cycle. However, there is large uncertainty on the estimation of soil organic carbon(SOC) storage in grassland among previous studies, and the study on soil inorganic carbon(SIC) is still lack. We surveyed 153 sites during plant peak growing season and estimated SOC and SIC for temperate desert, temperate steppe, alpine steppe, steppe meadow, alpine meadow and swamp, which covered main grassland in the Qinghai Plateau during 2011 to 2012. The results showed that the vertical and spatial distributions of SOC and SIC varied by grassland types. The SOC amount mainly decreased from southeast to northwest, whereas the SIC amount increased from southeast to northwest. The magnitude of SOC amount in the top 50 cm across grassland types ranked by: swamp > alpine meadow >steppe meadow > temperate steppe > alpine steppe > temperate desert, while the SIC amount showed an opposite order. There was a great deal of variation in proportion of SOC and SIC among different grassland types(from 55.17 to 94.59 for SOC and 5.14 to 44.83 for SIC). The total SOC and SIC storage was 5.78 Pg and 1.37 Pg, respectively, in the top 50 cm of soil in Qinghai Province. The mixed linear model revealed that grassland types was the predominant factor in spatial variations of SOC amount while grassland types and soil p H accounted for those of SIC amount. Our results suggested that the community shift of alpine meadow towards alpine grassland induced by climate warming would decrease carbon sequestration capacity by 6.0 kg C m2.
基金This study was financially supported by the National Natural Science Foundation of China(32101345).
文摘Litter decomposition is an important component of the nutrient recycling process and is highly sensitive to climate change.However,the impacts of warming and increased precipitation on litter decomposition have not been well studied,especially in the alpine grassland of Tianshan Mountains.We conducted a manipulative warming and increased precipitation experiment combined with different grassland types to examine the impact of litter quality and climate change on the litter decomposition rate based on three dominant species(Astragalus mongholicus,Potentilla anserina,and Festuca ovina)in Tianshan Mountains from 2019 to 2021.The results of this study indicated there were significant differences in litter quality,specific leaf area,and leaf dry matter content.In addition,litter quality exerted significant effects on litter decomposition,and the litter decomposition rate varied in different grassland types.Increased precipitation significantly accelerated the litter decomposition of P.anserina;however,it had no significant effect on the litter decomposition of A.mongholicus and F.ovina.However,warming consistently decreased the litter decomposition rate,with the strongest impact on the litter decomposition of F.ovina.There was a significant interaction between increased precipitation and litter type,but there was no significant interaction between warming and litter type.These results indicated that warming and increased precipitation significantly influenced litter decomposition;however,the strength was dependent on litter quality.In addition,soil water content played a crucial role in regulating litter decomposition in different grassland types.Moreover,we found that the litter decomposition rate exhibited a hump-shaped or linear response to the increase of soil water content.Our study emphasizes that ongoing climate change significantly altered litter decomposition in the alpine grassland,which is of great significance for understanding the nutrient supply and turnover of litter.
基金supported by the National Science and Technology Support Program of China (2014BAC15B04)
文摘Soil organic carbon(SOC) and soil total nitrogen(STN) in arid regions are important components of global C and the N cycles, and their response to climate change will have important implications for both ecosystem processes and global climate feedbacks. Grassland ecosystems of Funyun County in the southern foot of the Altay Mountains are characterized by complex topography, suggesting large variability in the spatial distribution of SOC and STN. However, there has been little investigation of SOC and STN on grasslands in arid regions with a mountain-basin structure. Therefore, we investigated the characteristics of SOC and STN in different grassland types in a mountain-basin system at the southern foot of the Altai Mountains, north of the Junggar Basin in China, and explored their potential influencing factors and relationships with meteorological factors and soil properties. We found that the concentrations and storages of SOC and STN varied significantly with grassland type, and showed a decreasing trend along a decreasing elevation gradient in alpine meadow, mountain meadow, temperate typical steppe, temperate steppe desert, and temperate steppe desert. In addition, the SOC and STN concentrations decreased with depth, except in the temperate desert steppe. According to Pearson's correlation values and redundancy analysis, the mean annual precipitation, soil moisture content and soil available N concentration were significantly positively correlated with the SOC and STN concentrations. In contrast, the mean annual temperature, p H, and soil bulk density were significantly and negatively correlated with the SOC and STN concentrations. The mean annual precipitation and mean annual temperature were the primary factors related to the SOC and STN concentrations. The distributions of the SOC and STN concentrations were highly regulated by the elevation-induced differences in meteorological factors. Mean annual precipitation and mean annual temperature together explained 97.85% and 98.38% of the overall variations in the SOC and STN concentrations, respectively, at soil depth of 0–40 cm, with precipitation making the greatest contribution. Our results provide a basis for estimating and predicting SOC and STN concentrations in grasslands in arid regions with a mountain-basin structure.
基金financially supported by the grants from the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0307)the National Key R&D Program of China(2016YFC0501906)+1 种基金Key R&D Program of Qinghai Province(2019-SF-145 and 2018-NK-A2)Qinghaiinnovation platform construction project(2017-ZJY20)。
文摘Owing to the joint effects of ecosystem fragility,anthropogenic disturbance and climate change,alpine grasslands(alpine meadow,alpine steppe and alpine desert)have experienced serious degradation during the past several decades.Grasslands degradation has severely affected the delivery of ecosystem multifunctionality(EMF)and services,and then threatens the livelihood of local herdsmen and ecological security of China.However,we still lack comprehensive insights about the effects of degradation and climatic factors on EMF of alpine grasslands,especially for alpine desert ecosystem.Therefore,we applied a large-scale field investigation to answer this question.Our results suggested grassland degradation significantly decreased the belowground ecosystem multifunctionality(BEMF)and EMF of alpine grasslands and aboveground ecosystem multifunctionality(AEMF)of alpine meadow,while did not reduce the AEMF of alpine steppe and desert.Except for the insignificant difference between degraded steppe and degraded desert in AEMF,the alpine meadow showed the highest AEMF,BEMF and EMF,alpine steppe ranked the second and alpine desert was the lowest.AEMF,BEMF and EMF of health alpine grasslands were strongly affected by mean annual precipitation(MAP)(19%-51%)and mean annual temperature(MAT)(9%-36%),while those of degraded meadow and degraded desert were not impacted by precipitation and temperature.AEMF and BEMF showed a synergistic relationship in healthy alpine grasslands(12%-28%),but not in degraded grasslands.Our findings emphasized the urgency of implementing the feasible ecological restoration project to mitigate the negative influences of grassland degradation on EMF of alpine ecosystems.
基金supported financially by the National Natural Science Foundation of China(41361140361,41271126)the Project of State Key Laboratory of Desert and Oasis Ecology(Y471163)
文摘Grazing is a main human activity in the grasslands of Xinjiang, China. It is vital to identify the effects of grazing on the sustainable utilization of local grasslands. However, the effects of grazing on net primary productivity(NPP), evapotranspiration(ET) and water use efficiency(WUE) in this region remain unclear. Using the spatial Biome-BGC grazing model, we explored the effects of grazing on NPP, ET and WUE across the different regions and grassland types in Xinjiang during 1979–2012. NPP, ET and WUE under the grazed scenario were generally lower than those under the ungrazed scenario, and the differences showed increasing trends over time. The decreases in NPP, ET and WUE varied significantly among the regions and grassland types. NPP decreased as follows: among the regions, Northern Xinjiang(16.60 g C/(m^2·a)), Tianshan Mountains(15.94 g C/(m^2·a)) and Southern Xinjiang(-3.54 g C/(m^2·a)); and among the grassland types, typical grasslands(25.70 g C/(m^2·a)), swamp meadows(25.26 g C/(m^2·a)), mid-mountain meadows(23.39 g C/(m^2·a)), alpine meadows(6.33 g C/(m^2·a)), desert grasslands(5.82 g C/(m^2·a)) and saline meadows(2.90 g C/(m^2·a)). ET decreased as follows: among the regions, Tianshan Mountains(28.95 mm/a), Northern Xinjiang(8.11 mm/a) and Southern Xinjiang(7.57 mm/a); and among the grassland types, mid-mountain meadows(29.30 mm/a), swamp meadows(25.07 mm/a), typical grasslands(24.56 mm/a), alpine meadows(20.69 mm/a), desert grasslands(11.06 mm/a) and saline meadows(3.44 mm/a). WUE decreased as follows: among the regions, Northern Xinjiang(0.053 g C/kg H_2O), Tianshan Mountains(0.034 g C/kg H_2O) and Southern Xinjiang(0.012 g C/kg H_2O); and among the grassland types, typical grasslands(0.0609 g C/kg H_2O), swamp meadows(0.0548 g C/kg H_2O), mid-mountain meadows(0.0501 g C/kg H_2O), desert grasslands(0.0172 g C/kg H_2O), alpine meadows(0.0121 g C/kg H_2O) and saline meadows(0.0067 g C/kg H_2O). In general, the decreases in NPP and WUE were more significant in the regions with relatively high levels of vegetation growth because of the high grazing intensity in these regions. The decreases in ET were significant in mountainous areas due to the terrain and high grazing intensity.
基金the National Basic Research Program of China(2010CB950702)the National High-Technology Reaearch and Development Program of China(2007AA10Z231)the Asia-Pacific Network for Global Change Research Project(ARCP201106CMY-Li)
文摘This research classified vegetation types and evaluated net primary productivity(NPP) of southern China's grasslands based on the improved comprehensive and sequential classification system(CSCS), and proposed 5 thermal grades and 6 humidity grades. Four classes of grasslands vegetation were recognized by improved CSCS, namely, tundra grassland class, typical grassland class, mixed grassland class and alpine grassland class. At the type level, 14 types of vegetations(9 grasslands and 5 forests) were classified. The NPP had a trend to decrease from east to west and south to north, and the annual mean NPP was estimated to be 656.3 g C m-2 yr-1. The NPP value of alpine grassland class was relatively high, generally more than 1 200 g C m-2 yr-1. The NPP value of mixed grassland class was in a range from 1 000 to 1 200 g C m-2 yr-1. Tundra grassland class was located in southeastern Tibet with high elevation, and its NPP value was the lowest(<600 g C m-2 yr-1). The typical grassland class distributed in most of the area, and its NPP value was generally from 600 to 1 000 g C m-2 yr-1. The total NPP value in the study area was 68.46 Tg C. The NPP value of typical grassland class was the highest(48.44 Tg C), and mixed grassland class was the second(16.54 Tg C), followed by alpine grassland class(3.22 Tg C), with tundra grassland class being the lowest(0.25 Tg C). For all the grasslands types, the total NPP of forest meadow was the highest(34.81 Tg C), followed by sparse forest brush(16.54 Tg C), and montane meadow was the lowest(0.01 Tg C).
基金The financial supports are greatly appreciated from the Central Public-interest Scientific Institution Basal Research Fund of China(1610322013003)the Agriculture Achievements Transformation Fund Project of the Ministry of Science and Technology of China(2010GB23260564)
文摘The purpose of the present study was to survey contents of trace elements of Cu,Mn,Fe,and Zn in the surface layer(0-20 cm) in the soil,pasture and serum of sheep in Huangcheng area of Qilian mountain grassland,China.Also the soil-plantanimal continuum was analyzed.Soil(n=300),pasture(n=60),and blood serum samples from sheep(n=480) were collected from Huangcheng area of Qilian mountain grassland,China.The contents of trace element in the samples were analyzed by atomic absorption spectrophotometer after digestion.The soil trace elements density distribution shows a ladder-like pattern distribution.Equations developed in the present study for prediction of Fe(R2=0.943) and Zn(R2=0.882) had significant R2 values.
基金funded by the National Natural Science Foundation of China(41165010)the State Key Basic Research and Development Plan of China(2007CB106806)the State Key Laboratory Fund of Institute of Atmospheric Physics,Chinese Academy of Sciences(LAPC-KF-2008-03)
文摘Land use change significantly influences soil properties.There is little information available on the long-term effects of post-reclamation from grassland to cropland on soil properties.We compared soil carbon(C) and nitrogen(N) storage and related soil properties in a 50-year cultivation chronosequence of grassland in the agro-pastoral ecotone of Inner Mongolia.Field surveys on land use changes during the period of 1955-2002 were conducted to build a chronosequence of cropland of different ages since the conversion from grassland.The results showed that soil C and N storage,soil texture,and soil nutrient contents varied with land use types and cropland ages(P<0.01).In the 0-30 cm soil layer,the soil organic carbon(SOC) density was significantly lower in the croplands(3.28 kg C/m2 for C50 soil) than in the grasslands(6.32 kg C/m2).After 5,10,15,20,35,and 50 years of crop planting(years since the onset of cultivation),the SOC losses were 17%,12%,19%,47%,46%,and 48%,respectively,compared with the grasslands.The soil total nitrogen(TN) density of the grasslands was 65 g N/m2,and TN density of the cropland soil was 35 g N/m2 after 50 years of crop planting.Both the SOC and TN densities could be quantitatively determined by a negative exponential function of cropland age(P<0.0001,R2=0.8528;P<0.0001,R2=0.9637).The dissolved organic carbon(DOC) content,soil available potassium(AK) content,clay content,and pH value were decreased;and the soil bulk density and sand content were increased since the conversion of grassland into cropland during the 50-year period.Our results show soil nutrients were higher in grassland than in cropland.The conversion of grasslands to croplands induced a loss of soil C storage and changes of related soil properties.The reclamation time of cultivated soil(cropland age) had significant effects on soil properties in the study area.
