Sulfur in Ghanaian soils

Studies were carried out to examine factors which might influence the distribution of S in Ghanaian soils. Nine soil profiles developed over granitic rocks, three each representing the upper slope (US), middle slope (MS) and lower slope (LS) of catena in the evergreen high rain forest (ERF), semi-deciduous rain forest (SDF) and the interior savanna (ISAV) zone of Ghana were selected. The total S contents varied from 9 to 347 ppm; the average for all the surface and subsurface horizons was 141 ppm and for subsoils 105 ppm. The contents also varied according to: (1) the ecological zone as follows: ERF 0) SDF>ISAV and (2) the topographic position: US>MS>LS. The total S was closely correlated with organic C and total N in the surface and subsurface horizons (r=0.931*** and 0.941*** respectively). Inorganic sulfate was generally higher in the subsoils than in the surface and subsurface horizons of the ERF and SDF profiles whereas the opposite was the case in the ISAV profiles. Based on the critical value of 6 ppm in surface soils, all the savanna soils would be considered S deficient.