The soil organic carbon (SOC) pool is the largest component of terrestrial carbon pools. With the construction of a geographically referenced database taken from the second national general soil survey materials and b...The soil organic carbon (SOC) pool is the largest component of terrestrial carbon pools. With the construction of a geographically referenced database taken from the second national general soil survey materials and based on 1546 typical cropland soil profiles, the paddy field and dryland SOC storage among six regions of China were systematically quantified to characterize the spatial pattern of cropland SOC storage in China and to examine the relationship between mean annual temperature, precipitation, soil texture features and SOC content. In all regions, paddy soils had higher SOC storage than dryland soils, and cropland SOC content was the highest in Southwest China. Climate controlled the spatial distribution of SOC in both paddy and dryland soils, with SOC storage increasing with increasing precipitation and decreasing with increasing temperature.展开更多
New progresses are introduced briefly about the water cycle study on atmosphere of China made in recent years. The introduction includes eight aspects as follows: 1) precipitation characteristics, 2) stability of clim...New progresses are introduced briefly about the water cycle study on atmosphere of China made in recent years. The introduction includes eight aspects as follows: 1) precipitation characteristics, 2) stability of climatic system, 3) precipitation sensitive region, 4) regional evaporation and evapotranspiration, 5) water surface evaporation, 6) vegetation transpiration, 7) cloud physics, and 8) vapor source.展开更多
The patterns of soil nitrogen(N) isotope composition at large spatial and temporal scales and their relationships to environmental factors illustrate N cycle and sources of N,and are integrative indicators of the terr...The patterns of soil nitrogen(N) isotope composition at large spatial and temporal scales and their relationships to environmental factors illustrate N cycle and sources of N,and are integrative indicators of the terrestrial N cycle and its response to global change. The objectives of this study were:i) to investigate the patterns of soil N content and natural abundance of 15N(δ15N) values in different ecosystem types and soil profiles on the Qinghai-Tibetan Plateau; ii) to examine the effects of climatic factors and soil characteristics on the patterns of soil N content and soil δ15N values; and iii) to test the relationship between soil δ15N values and soil C/N ratios across ecosystems and soil profiles. Soil profiles were sampled at 51 sites along two transects 1 875 km in length and 200 km apart and distributed in forest,meadow and steppe on the Qinghai-Tibetan Plateau. Each site was sampled every 10 cm from a soil depth of 0 to 40 cm and each sample was analyzed for soil N content and δ15N values. Our results indicated that soil N and δ15N values(0–40 cm) in meadows were much higher than in desert steppe. Soil N decreased with soil depth for each ecosystem,while variations of soil δ15N values along soil profiles were not statistically significant among most ecosystems but for mountain meadow,lowland meadow,and temperate steppe where soil δ15N values tended to increase with soil depth. The parabolic relationship between soil δ15N values and mean annual precipitation indicated that soil δ15N values increased with increasing precipitation in desert steppe up to 500 mm,and then decreased with increasing precipitation across all other ecosystems. Moreover,the parabolic relationship between δ15N values and mean annual temperature existed in all individual ecosystem types. Soil N and δ15N values(0–40 cm) increased with an increase in soil silt and clay contents. Furthermore,a threshold of C/N ratio of about 11 divided the parabolic relationship between soil δ15N values and soil C/N ratios into positive(C/N < 11) and negative(C/N > 11) parts,which was valid across all ecosystems and soil profiles. The large explanatory power of soil C/N ratios for soil δ15N values suggested that C and N concentrations,being strongly controlled by precipitation and temperature,were the primary factors determining patterns of soil δ15N on the Qinghai-Tibetan Plateau.展开更多
基金Project supported by the National Key Basic Research and Development Program of China (No. 2002CB412501), theKnowledge Innovation Key Project of Chinese Academy of Sciences (No. KZCX1-SW-01-19), and the Integrated Interdis-ciplinary Science Plan of Land-Use/Land-Cover and Terrestrial Carbon Process of Institute of Geographical Sciences andNatural Resources Research (No. CXIOG-E01-02-02).
文摘The soil organic carbon (SOC) pool is the largest component of terrestrial carbon pools. With the construction of a geographically referenced database taken from the second national general soil survey materials and based on 1546 typical cropland soil profiles, the paddy field and dryland SOC storage among six regions of China were systematically quantified to characterize the spatial pattern of cropland SOC storage in China and to examine the relationship between mean annual temperature, precipitation, soil texture features and SOC content. In all regions, paddy soils had higher SOC storage than dryland soils, and cropland SOC content was the highest in Southwest China. Climate controlled the spatial distribution of SOC in both paddy and dryland soils, with SOC storage increasing with increasing precipitation and decreasing with increasing temperature.
基金Knowledge Innovation Program of CAS No. KZCX1-10-07+3 种基金 National Natural Science Foundation of China No. 49971078 Knowledge Innovation Project of CAS No. KZCX2-314
文摘New progresses are introduced briefly about the water cycle study on atmosphere of China made in recent years. The introduction includes eight aspects as follows: 1) precipitation characteristics, 2) stability of climatic system, 3) precipitation sensitive region, 4) regional evaporation and evapotranspiration, 5) water surface evaporation, 6) vegetation transpiration, 7) cloud physics, and 8) vapor source.
基金Supported by the National Basic Research Program(973 Program)of China(No.2010CB833503)the Chinese Academy of Sciences for Strategic Priority Research Program(No.XDA05050602)+1 种基金the Key Projects in the National Science and Technology Pillar Program(No.2013BAC03B03)the Open Research Fund of Chinese Academy of Sciences(No.O8R8B161PA)
文摘The patterns of soil nitrogen(N) isotope composition at large spatial and temporal scales and their relationships to environmental factors illustrate N cycle and sources of N,and are integrative indicators of the terrestrial N cycle and its response to global change. The objectives of this study were:i) to investigate the patterns of soil N content and natural abundance of 15N(δ15N) values in different ecosystem types and soil profiles on the Qinghai-Tibetan Plateau; ii) to examine the effects of climatic factors and soil characteristics on the patterns of soil N content and soil δ15N values; and iii) to test the relationship between soil δ15N values and soil C/N ratios across ecosystems and soil profiles. Soil profiles were sampled at 51 sites along two transects 1 875 km in length and 200 km apart and distributed in forest,meadow and steppe on the Qinghai-Tibetan Plateau. Each site was sampled every 10 cm from a soil depth of 0 to 40 cm and each sample was analyzed for soil N content and δ15N values. Our results indicated that soil N and δ15N values(0–40 cm) in meadows were much higher than in desert steppe. Soil N decreased with soil depth for each ecosystem,while variations of soil δ15N values along soil profiles were not statistically significant among most ecosystems but for mountain meadow,lowland meadow,and temperate steppe where soil δ15N values tended to increase with soil depth. The parabolic relationship between soil δ15N values and mean annual precipitation indicated that soil δ15N values increased with increasing precipitation in desert steppe up to 500 mm,and then decreased with increasing precipitation across all other ecosystems. Moreover,the parabolic relationship between δ15N values and mean annual temperature existed in all individual ecosystem types. Soil N and δ15N values(0–40 cm) increased with an increase in soil silt and clay contents. Furthermore,a threshold of C/N ratio of about 11 divided the parabolic relationship between soil δ15N values and soil C/N ratios into positive(C/N < 11) and negative(C/N > 11) parts,which was valid across all ecosystems and soil profiles. The large explanatory power of soil C/N ratios for soil δ15N values suggested that C and N concentrations,being strongly controlled by precipitation and temperature,were the primary factors determining patterns of soil δ15N on the Qinghai-Tibetan Plateau.
