97 

 average of 5.6 ppm of sulfate S and 40 ppm of total S in the subsurface 

 horizons. Soil texture and mineralogy changed very little with in- 

 creasing depth in the profile which is characteristic of Entisols. 



The large difference in total S from the surface horizons to the 

 lower horizons was due to organic S. As in the Spodosols , total S was 

 significantly correlated with organic C (r = 0.91) and total N (r = 

 0.97) in surface horizons (Table 15). 



Extractable sulfate S was not highly correlated with any of the 

 parameters studied in either the surface or subsurface horizons. Low 

 correlations were also found with total S and the soil properties ob- 

 served in subsurface horizons. 



The surface 15 cm contained an average of 13 kg/ha of total 

 extractable sulfate S. The Pompano and Ft. Meade soils were unusually 

 high in both total and extractable S. If these are excluded from cal- 

 culations, then an average of only 5 to 6 kg/ha of extractable S was 

 available in the surface 15 cm of the other eight Entisols. Because of 

 the lack of extensive profile development and the sandy texture of 

 these soils, plant roots can penetrate several meters. Plants such as 

 legumes which lack a fibrous root system and have a high S requirement 

 may have difficulty obtaining adequate S from these soils even though 

 an average of over 140 kg/ha of sulfate S is available within the 

 upper 2 m. 

 7.3 ULTISOLS 



The ten Ultisols showed the largest differences in S distribution 

 with profile depth of the three soil orders studied (Table 16, Fig. 9). 

 Extractable S was also very low in the surface horizons of these soils. 



