SECTION III 

 MATERIALS AND METHODS 



4. EXPERIMENTAL METHODS 



4.1 SULFUR DISTRIBUTION IN SELECTED FLORIDA SOILS 



Soil series which represented some of the major soils of Florida 

 and which are important in crop production were selected. These were 

 grouped into the orders Ultisols, Entisols , and Spodosols. The county 

 where profile samples were taken and the soil order are shown in 

 Fig. 4. 



Pedon samples were collected by personnel of the Soil Characteri- 

 zation Laboratory of the University of Florida. Samples were taken 

 from each horizon or subhorizon and prepared for physical, chemical, 

 and mineralogical analyses for characterization purposes (Calhoun et 

 al., 1974; Carlisle et al., 1978). After all characterization data 

 were collected, the air-dried, screened samples were used for extract- 

 able sulfate, total S, total C, and total N determinations by the 

 author. Ten Ultisols, ten Entisols, and nine Spodosols were selected 

 and a total of 174 profile samples were studied. The parameters were 

 compared and correlated with chemical and mineralogical data collected 

 by the Soil Characterization Laboratory on these same samples. Chemi- 

 cal methods used for analyses will be discussed in sections 5 and 6. 



4.2 A GREENHOUSE EVALUATION OF SUBSOIL 

 SULFJR IN FOUR FLORIDA SOILS 



A greenhouse experiment was designed to evaluate the contribution 



of subsurface horizons to the S nutrition of plants. Trie experiment 



62 



