Nature of Cementing Materials in Ortstein Horizons of Selected Florida Spodosols: I. Constituents of Cementing Materials
- F. Y. Lee,
- T. L. Yuan and
- V. W. Carlisle
Five pairs of ortstein and nonortstein spodic horizons of Haplaquods were studied in an attempt to identify the nature of cementing materials. The ortstein horizons had significantly larger amounts of dithionite-citrate-extractable Al, significantly higher silt plus clay contents, and significantly higher bulk density values than did nonortstein spodic horizons. Moist and air-dried ortstein samples had similar shear strengths, but the strength significantly decreased by 14 to 82% for oven-dried samples. The strength had a significant correlation with the dithionite-citrate-extractable Al. Energy-dispersive spectra showed that Si and Al were major constituents of both ortstein and nonortstein samples. Ortstein samples had stronger Al peaks, however. More cementing materials were observed in the ortstein than nonortstein samples in scanning electron micrographs. These cementing materials consisted of gel-like substances and fine particles. Cracks in dry gel-like substances between coarse particles were also observed. Electron-dot pictures revealed that the gel-like substances were Al-dominated.
Copyright © .