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Bodenchronosequenzen aus Lockersedimenten der Lechterrassen
Author(s) -
Wilke B. M.
Publication year - 1975
Publication title -
zeitschrift für pflanzenernährung und bodenkunde
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 0044-3263
DOI - 10.1002/jpln.19751380206
Subject(s) - pedogenesis , illite , geology , soil water , weathering , organic matter , loess , carbonate , silt , vermiculite , mineralogy , geochemistry , clay minerals , soil science , chemistry , geomorphology , paleontology , organic chemistry
Soil Chronosequences derived from Non‐Consolidated Sediments of the River Lech Terraces. . During the glacial and postglacial periods 16 river terraces were formed in the Lech Valley. Their non‐eroded soils derived from carbonate rich gravel and from silt represent two chronosequences. The aim of this paper is to describe 9 series of the terraces No. 1, 8, 10, 13, 14 and 15 and to explain their genesis regarding the time as a soil forming factor. Due to the result of this paper the following conclusions were made: 1 It is assumed that the decalcification of the sediments started immediately after the terrace formation. With growth of vegetation the decalcification rate increased, with increasing age of the soils it decreased again. 2 Organic matter content of the soil remained constant for a long time. 3 Because of the high carbonate contents of the sediments the soils became acid very slowly. Even in the stadium of a brown earth (after approximately 3000 years) the grade of acidity is still minor. 4 The total CEC of the soils depends not so much on their age as on their thickness and their content of organic matter. The accretion of organic matter has the highest influence on the CEC increase in the initial stages of soil formation. 5 The silicate weathering started before the bulk sample was decalcificated completely. 6 Clay minerals were converted in the following way: Illite (mica) → Vermiculite → pedogenic Chlorite Smectites wheathered already in the stage of a brown earth (profile B 3 ). 7 Clay illuvation took place shortly after the decalcification of the upper horizons. A reddish brown plasma was formed in the brown earths (B 1 , B 2 ) and the red brown podsolics (L 1 , L 2 ). It imparts the intensiv colour (5 YR 4/8) of the argillic horizons. The hue of this plasma is not due to a higher iron contents. It is presumed that the red plasma was formed during the Boreal, because the soils which derived from silt contain only a brown plasma. .