In order to understand the effect of different land use on soil physics and nutrients properties of the debris flow bottomland, a case study at Daqing gully （in Xiaojiang Basin, Yunnan） was conducted in 2004. Soil s...In order to understand the effect of different land use on soil physics and nutrients properties of the debris flow bottomland, a case study at Daqing gully （in Xiaojiang Basin, Yunnan） was conducted in 2004. Soil samples were taken at depth of 0-10,10-20,20-40,40-60,60-80 cm under three land use patterns crop bottomland （CL）, forest bottomland （FL）, and barren bottomland（BL）. The results showed that the developing bottomland to CL promoted soil toaccumulate total phosphorus （TP） and available phosphorus （AP）, pH value transferred from neutral to alkalescency, and organic matter decreased significantly. Furthermore, the contents of total nitrogen （TN） and available nitrogen （AN） in CL were lower than that of FL and BL because the growth of crops consumed more nutrients in soil. The results also showed that the contents of TP, AP and available potassium （AK） in soil were positively correlated with soil particle.展开更多
Sedimentary sequences with drastic thickening over short distances have been observed in Qiaojia County,Yunnan Province,Southwest China.These are related to a pull-apart basin controlled by the Xiaojiang strike-slip f...Sedimentary sequences with drastic thickening over short distances have been observed in Qiaojia County,Yunnan Province,Southwest China.These are related to a pull-apart basin controlled by the Xiaojiang strike-slip fault.Our field investigations include determining the surface characteristics of the Qiaojia basin which consists of three terrace sequences and a series of alluvial fans.Several drill holes were used to reveal the internal structure of the basin.The results suggest that the basinal sediments are over 300 m thick.From bottom to top,they can be classified into five different units.We inferred that the units of lacustrine sediments are deposited in a paleolake which was formed by a paleo-landslide.Accelerator mass spectrometry radiocarbon dating(AMS ^(14)C dating) was used to estimate the ages of the terrace and lacustrine sediments.We use the results to infer that the paleo-lake has existed about 15,000 years and that the Qiaojia basin was uplifted at an average rate of 3.3 mm/a.Furthermore,we then model the evolution process of the basin and interpreted 6 phases of development.展开更多
文摘In order to understand the effect of different land use on soil physics and nutrients properties of the debris flow bottomland, a case study at Daqing gully （in Xiaojiang Basin, Yunnan） was conducted in 2004. Soil samples were taken at depth of 0-10,10-20,20-40,40-60,60-80 cm under three land use patterns crop bottomland （CL）, forest bottomland （FL）, and barren bottomland（BL）. The results showed that the developing bottomland to CL promoted soil toaccumulate total phosphorus （TP） and available phosphorus （AP）, pH value transferred from neutral to alkalescency, and organic matter decreased significantly. Furthermore, the contents of total nitrogen （TN） and available nitrogen （AN） in CL were lower than that of FL and BL because the growth of crops consumed more nutrients in soil. The results also showed that the contents of TP, AP and available potassium （AK） in soil were positively correlated with soil particle.
基金funded by the Major State Basic Research Development Program of China(2013CB733200)the State Key Program of National Natural Science of China(41572302)
文摘Sedimentary sequences with drastic thickening over short distances have been observed in Qiaojia County,Yunnan Province,Southwest China.These are related to a pull-apart basin controlled by the Xiaojiang strike-slip fault.Our field investigations include determining the surface characteristics of the Qiaojia basin which consists of three terrace sequences and a series of alluvial fans.Several drill holes were used to reveal the internal structure of the basin.The results suggest that the basinal sediments are over 300 m thick.From bottom to top,they can be classified into five different units.We inferred that the units of lacustrine sediments are deposited in a paleolake which was formed by a paleo-landslide.Accelerator mass spectrometry radiocarbon dating(AMS ^(14)C dating) was used to estimate the ages of the terrace and lacustrine sediments.We use the results to infer that the paleo-lake has existed about 15,000 years and that the Qiaojia basin was uplifted at an average rate of 3.3 mm/a.Furthermore,we then model the evolution process of the basin and interpreted 6 phases of development.
