• Korean Journal of Soil Science and Fertilizer
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• v.22 no.2
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• pp.131-137
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• 1989

Chemical and microbial characteristics of root zone of neighboring large and small ginseng in a high yield field were investigated in relation to root growth. $NO_3-N$, $NH_4-N$, and available P contents were significantly low for large root but Ca high. The contents of $NO_3-N$ or $NH_4-N$ showed significant negative correlation with fine root development. Precipitation quotient of humic acid tended to be high for large roots. The population of one dominant bacteria was significantly high for large root. The ratios of bacteria to fungi or actinomycetes were positively correlated with fine root development.

• The Journal of the Petrological Society of Korea
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• v.14 no.3 s.41
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• pp.149-156
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• 2005

Ar-Ar, carbon AMS and OSL dating was carried out to clarify the age of the human footmarks on the Hamori Formation, Jeju Island, Korea. $^{40}Ar/^{39}Ar$ ages of trachybasalt from the Songaksan Tuff, which is underlain by the Hamori Formation, range between $10.6{\pm}19.9\;Ka$ and $11.7{\pm}26.3\;Ka$. Radiocarbon AMS ages of humin fractions extracted from sediment samples yielded the maximum limit age of the Hamori Formation as $15,161{\pm}70\;yr$ B.P. The OSL dating of the top and bottom layers of the Hamori Formation gave $6.8{\pm}0.3\;ka$ and $7.6{\pm}0.5\;ka$, respectively, suggesting that timing of the human footmarks formation can be constrained as between ca 6,800 yr B.P. and 7,600 yr B.P.