146 

 The same trend was observed with the N:S ratios in bermudagrass as 

 with bahiagrass (Tables 27 and 31). The highest mean ratio, 12.3, was 

 from the treatment without S but with a high rate of N. Most of the 

 N:S ratios were much less than this and well within the optimum range 

 for plant protein. 



As previously mentioned, S uptake was highly correlated with for- 

 age yield (Table 28) . There were significant differences in S uptake 

 with S fertilization. Even where no S was applied, 16.4 kg/ha of S 

 yere removed at low N rates. At high S and N rates, more than twice 



this amount was removed in the forage. Assuming a bulk density of 



3 

 1.3 g/cm , and using mean total S levels from Table 33, the author 



found that the upper 30 cm of this soil contains 164 kg/ha of S of 



which only 6 kg/ha were available to plants at any one time. 



10. SOURCES AND CYCLING OF SULFUR IN THE FIELD 



Data from these experiments and from other research have been com- 

 bined to estimate the sources and cycling of S in a Florida Spodosol 

 with a bahiagrass sward (Fig. 17). Estimates of sources of plant 

 available S have been made wherever possible. Most values are quite 

 variable but all have come from reliable data collected in the south- 

 eastern United States from soils or conditions similar to rural north 

 Florida. No attempt was made to balance the input and uptake of S by 

 bahiagrass because of the lack of certain essential values such as 

 annual leaching losses of S and S mineralization rates for Florida 

 soils. 



Edgerton et al. (1980) found a mean of 2.6 kg/ha of sulfate S was 

 deposited in northern Florida during the winter months and 5.8 kg/ha 

 during the summer months. These values were an average from 12 



