DISTRIBUTION OF CARBON, NITROGEN, SULPHUR AND PHOSPHORUS IN PARTICLE-SIZE SEPARATES FROM GLEYSOLIC SOILS

Abstract

Levels of C, N, S and organic P (P o ) were determined in fine, medium and coarse clay- and silt-size separates obtained from five Gleysolic soils by an ultrasonic dispersion method. Contents of C, N, S and P o increased with decreasing particle size, with average C values increasing from 3.7% in the silt to 10.1% in fine clay fractions. The corresponding increases for N, S and P o were 0.26–1.17%, 0.037–0.178% and 0.043–0.172%, respectively. C/N and C/S ratios decreased with decreasing particle size, indicating a relative enrichment of N and S in the finer particle-size fractions. N/S showed little variation with particle size, while C/P o ratios were erratic. The three clay fractions accounted on average for 31.3% of the soil material, and for 39.1% of soil carbon. In contrast, the clay fractions together accounted on average for 52–59% of soil N, S and P o .