HR: 1330h
AN: H42C-1085    [PDF]
TI: Heterogeneous Soil Morphology on the Taoyuan Terrace, Northwestern Taiwan
AU: * Lin, Y
EM: yushin1492@yahoo.com.tw
AF: Dept of Geosciences, NTU, No.1, Sec. 4, Roosevelt Road, Taipei, 106 Taiwan
AU: Chen, Y
EM: ygchen@ccms.ntu.edu.tw
AF: Dept of Geosciences, NTU, No.1, Sec. 4, Roosevelt Road, Taipei, 106 Taiwan
AU: Chen, Z
EM: soilchen@ccms.ntu.edu.tw
AF: Dept of Agri. Chem., NTU, No.1, Sec. 4, Roosevelt Road, Taipei, 106 Taiwan
AU: Hsieh, M
EM: hsiehml@pchome.com.tw
AF: Dept of Geosciences, NTU, No.1, Sec. 4, Roosevelt Road, Taipei, 106 Taiwan
AB: In this study ­soil geomorphology­" is selected to work on the reciprocal relationship between the landscape evolution and soil genesis. Among geological studies on the Taoyuan area, it has remained a concern to apply lateritisation as an index on terrace correlation. To answer this question, the basic knowledge of laterite formation must be clearly understood. On the other hand, pedologists have long been interested in the genesis of laterite, especially those thick ones on the higher terraces. To give insights pedosequences must be built up to distinguish the influence of specific factor. Without assistance of geological data, this goal is hardly achieved. In spite of the obvious demand of interdisciplinary integration, it is short of dialogue between geology and pedology in Taiwan until the last decade when the first soil chronosequence was established in this area. However, the tacit assumption that soils on one geomorphic surface were homogeneous has never been carefully examined. A later study on soil toposequence in the coastal area of Taoyuan terraces soon discovered that soils on one surface were heterogeneous both morphologically and chemically. This finding was explained as the influence of the seasonal undulation of groundwater table. To understand whether the upland soils on geomorphic surfaces are also heterogeneously developed, the soil morphology on the Taoyuan Terrace is selected as target being carefully studied. The relationships among the soil morphology, the undulation of groundwater table (GWT), and the processes of soil formation are established by field investigation and previously reported datasets. Based on recompilation of the published soil maps, the soil series in study area can be divided into eight groups. To compare the soil morphology and assess the reliability of the soil maps, fifteen hand cores are drilled in the field. The datasets of engineering boreholes are also collected to assist the explanation on the spatial variation of soil morphology. We discovered that the soil morphology systematically changes from the terrace edge to the interior, showing a toposequence of red soil, orange soil, yellow soil, mottled soil, and gley soil. Based on the profile reconstructed by the engineering borehole data, the GWT is inconsistent with the subsurface lithology but controlled by the terrace geomorphology. Since soils on the terrace edge are usually developed in well-drained condition for lateritisation, we consequently suggest that they are the best prospective soils for terrace correlation.
DE: 1824 Geomorphology (1625)
DE: 1829 Groundwater hydrology
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: 2003 Fall Meeting