Wang FL;Huang PM

Department of Soil Science, University of Saskatchewan, Saskatoon, S7N 5A8, Canada.;

minerals alluvial soils;loam soils;clay soils;interstratified minerals;clay minerals;paddy soils;mineralogy soil types;marine sediments;china

The mineral composition of three paddy soils: Jinghua (paddy soil on Quaternary red clay), Fuyang (alluvial loamy paddy soil), and Shaoxing (marine gleyic clayey paddy soil), was studied. All the soils contained quartz, mica, vermiculite, chlorite and kaolinite, and the distribution of these minerals varied with soil particle size fractions. The clay fraction of the Fuyang and Shaoxing soils also contained smectite. Although X-ray data did not show the presence of smectite in the Jinghua soil, thismineral was identified by the chemical method, suggesting a transitional property of the mineral in the soil. Hydroxy-Al interlayered minerals were also present in the clay fraction. The amount of smectite in the soils was 31.6 (Shaoxing), 16.5 (Fuyang), and 21.4 (Jinghua) g/kg; for vermiculite it was 33.3 (Shaoxing), 16.5 (Fuyang), and 8.5 (Jinghua) g/kg. Smectite was only found in the clay fraction. In contrast, amounts of vermiculite in soil particle size fractions were 3.0-11.4 (sand), 2.1-6.0 (coarse silt), 4.6-18.9 (medium silt), 0.9-40.0 (fine silt), and 17.0-108 (clay) g/kg. Non-crystalline aluminosilicates in the soils in g/kg were: 2.4 (Shaoxing), 1.9 (Jinghua) and 1.7 (Fuyang).