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Pedological response in the humus properties of andisols to vegetation and climate changes during the holocene
Part III - - Abstracts
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PEDOLOGICAL RESPONSE IN ME HUMUS PROPERTIES OF ANDISOLS TO VEGETATION AND CLIMATE CHANGES DURING THE HOLOCENE Makiko Watanabe,* Kan-ichi Sakagamit and Shinji Sugiyama$ * Chuo Gakuin University, Chiba, Japan t Tokyo University of Agriculture and Technology, Tokyo, Japan Paleoenvironment Research Co. Ltd, Miyazaki, Japan
In profiles of Andisols in many parts of Japan, we can generally notice the extremely black and humic horizons identified as buried A horizons which are dated approximately 5 ~ years BP, the period known as Hypsithermal or Holocene optimum. Yoshida et al. (1978) and Sakagami (1988) found that humification degree expressed in terms of RF values of humic acids tends to reach a maximum value in buried A horizons. Our interest is to establish a reliable method for obtaining quantitative information on environmental changes in the past by examining humus properties of buried horizons of Andisols derived from Holocene volcanic ashes (Watanabe et al., 1991, 1993; Watanabe, 1992). As Birkeland (1984) noted, a paleoclimatic reconstruction might be possible if some of the properties of organic matter could be shown to have been inherited from a former vegetation cover, and if the change in vegetation was due to a change in climate. In this study, carbon content, humus composition and Pg absorption strength of humic acids were investigated through several representative profiles of Andisols in Japan. The ages of buried A horizons were determined by 14C analysis. We also examined phytolith composition to infer the dominant vegetation cover which supplied humus in the past. The yield of vegetation (kg/m2cm) was estimated from the density of phytolith particles per unit of soil. Analyzed data were compared with present climatic data and previous paleoclimatic interpretations presented by Sakaguchi (1982), Clapperton (1989) and others.
From this study we detected biological influence on Pg absorption in the buried A horizons. In our experience with cool forest zones, we regard that grass vegetation strongly regulates the strength of Pg absorption. Particularly, Miscanthus has a negative influence and Bambusoide Sasa has a positive influence on Pg absorption strength. As we have confirmed a strong positive relationship between the yield of Bambusoide Sasa and cool conditions by examining surface A horizons, we may say that climatic changes contribute to the appearance of Pg absorption of humic acids. However, we cannot disregard the influence of human activity when we examine the vegetational changes during the Holocene.
REFERENCES Birkeland, P.W. (1984). Soil and Geomorpholo#y. Oxford University Press, New York, 372 pp. Clapperton, C.M. (1989). Quaternary Research, 31, 210-228. Sakaguchi, Y. (1982). Bulletin Department of Geography, University of Tokyo 14, 1-27. Sakagami, K. (1988). Pedologist, 32, 181-188 (in Japanese). Watanabe, M. (1992). The Science of Total Environment, 117/118, 293-304. Watanabe, M. and Sakagami, K. (1991). Abstract of INQUA 13th Congress, Beijing, 386 pp. Watanabe, M., Sakagami, K., Aoki, K. and Sugiyama, S. (1993). Journal of Geography, 102(5), 21-35 (in Japanese). Yoshida, M., Sakagami, K., Hamada, R. and Kurobe, T. (1978). Soil Science Plant Nutrition, 24, 277-287.
PALEOSOLS AND THEIR RELATION TO SEA LEVEL CHANGES DURING THE LATE QUATERNARY IN MAR CHIQUITA, BUENOS AIRES, ARGENTINA Margarita L. Osterrieth Centro de Geologia de Costas y del Cuaternario-UNMDP, C.C. 722 C-Central, 7600 Mar del Plata, Argentina
Paleosols present in exposed stratigraphical sequences of the Mar Chiquita coastal plain were analyzed, which include continental and littoral deposits. The characterization of these paleosols allows us to interpret pedogenetic processes, to make pedostratigraphic correlations with neighboring areas and to infer the timing of different sea level positions during the late Pieistocene-Holocene. Soils that evolved in the highest landscape positions belong to the 'Complex'
type, developed during late Pleistocene continental and transitional events. These profiles are welt developed and have clay enriched illuvial horizons; some are sodium enriched and range from the Hydromorphic sodium-saline types to Brunizem types. In lower topographic areas the soils in marshy environments evolved on the regressive estuarine deposits that range from anoxic to oxic and developed into soils of the Gley-subhumic type. These soils are
43
PEDOLOGICAL RESPONSE IN ME HUMUS PROPERTIES OF ANDISOLS TO VEGETATION AND CLIMATE CHANGES DURING THE HOLOCENE Makiko Watanabe,* Kan-ichi Sakagamit and Shinji Sugiyama$ * Chuo Gakuin University, Chiba, Japan t Tokyo University of Agriculture and Technology, Tokyo, Japan Paleoenvironment Research Co. Ltd, Miyazaki, Japan
In profiles of Andisols in many parts of Japan, we can generally notice the extremely black and humic horizons identified as buried A horizons which are dated approximately 5 ~ years BP, the period known as Hypsithermal or Holocene optimum. Yoshida et al. (1978) and Sakagami (1988) found that humification degree expressed in terms of RF values of humic acids tends to reach a maximum value in buried A horizons. Our interest is to establish a reliable method for obtaining quantitative information on environmental changes in the past by examining humus properties of buried horizons of Andisols derived from Holocene volcanic ashes (Watanabe et al., 1991, 1993; Watanabe, 1992). As Birkeland (1984) noted, a paleoclimatic reconstruction might be possible if some of the properties of organic matter could be shown to have been inherited from a former vegetation cover, and if the change in vegetation was due to a change in climate. In this study, carbon content, humus composition and Pg absorption strength of humic acids were investigated through several representative profiles of Andisols in Japan. The ages of buried A horizons were determined by 14C analysis. We also examined phytolith composition to infer the dominant vegetation cover which supplied humus in the past. The yield of vegetation (kg/m2cm) was estimated from the density of phytolith particles per unit of soil. Analyzed data were compared with present climatic data and previous paleoclimatic interpretations presented by Sakaguchi (1982), Clapperton (1989) and others.
From this study we detected biological influence on Pg absorption in the buried A horizons. In our experience with cool forest zones, we regard that grass vegetation strongly regulates the strength of Pg absorption. Particularly, Miscanthus has a negative influence and Bambusoide Sasa has a positive influence on Pg absorption strength. As we have confirmed a strong positive relationship between the yield of Bambusoide Sasa and cool conditions by examining surface A horizons, we may say that climatic changes contribute to the appearance of Pg absorption of humic acids. However, we cannot disregard the influence of human activity when we examine the vegetational changes during the Holocene.
REFERENCES Birkeland, P.W. (1984). Soil and Geomorpholo#y. Oxford University Press, New York, 372 pp. Clapperton, C.M. (1989). Quaternary Research, 31, 210-228. Sakaguchi, Y. (1982). Bulletin Department of Geography, University of Tokyo 14, 1-27. Sakagami, K. (1988). Pedologist, 32, 181-188 (in Japanese). Watanabe, M. (1992). The Science of Total Environment, 117/118, 293-304. Watanabe, M. and Sakagami, K. (1991). Abstract of INQUA 13th Congress, Beijing, 386 pp. Watanabe, M., Sakagami, K., Aoki, K. and Sugiyama, S. (1993). Journal of Geography, 102(5), 21-35 (in Japanese). Yoshida, M., Sakagami, K., Hamada, R. and Kurobe, T. (1978). Soil Science Plant Nutrition, 24, 277-287.
PALEOSOLS AND THEIR RELATION TO SEA LEVEL CHANGES DURING THE LATE QUATERNARY IN MAR CHIQUITA, BUENOS AIRES, ARGENTINA Margarita L. Osterrieth Centro de Geologia de Costas y del Cuaternario-UNMDP, C.C. 722 C-Central, 7600 Mar del Plata, Argentina
Paleosols present in exposed stratigraphical sequences of the Mar Chiquita coastal plain were analyzed, which include continental and littoral deposits. The characterization of these paleosols allows us to interpret pedogenetic processes, to make pedostratigraphic correlations with neighboring areas and to infer the timing of different sea level positions during the late Pieistocene-Holocene. Soils that evolved in the highest landscape positions belong to the 'Complex'
type, developed during late Pleistocene continental and transitional events. These profiles are welt developed and have clay enriched illuvial horizons; some are sodium enriched and range from the Hydromorphic sodium-saline types to Brunizem types. In lower topographic areas the soils in marshy environments evolved on the regressive estuarine deposits that range from anoxic to oxic and developed into soils of the Gley-subhumic type. These soils are