57 



respirometer degree of S deficiency assessed by comparing 



respiration curves with and without applied S. 



short-term uptake intense, short-term extraction by root pods 



of turnips or wheat. 



3. SULFUR FERTILITY STUDIES IN FLORIDA 

 Most of the research with S as a plant nutrient occurred during 

 the 1950 's and 1960's as is evident by the citations in this paper. 

 An important contribution to this research was by scientists studying 

 crops and soils in the southeastern United States (Ensminger, 1954; 

 Neller, 1959; Kilmer and Nearpass , 1960; Chang and Thomas, 196 3; 

 Jordan, 1964; Nelson, 1964a). By 1971, S deficiencies had been identi- 

 fied or suspected in every state in the Southeast (Beaton et al. , 

 1971) . Most of the S-deficient crops were on the sandy soils of the 

 Coastal Plain. The Coastal Plain includes all of Florida, but only 

 the coarse-textured soils of north and central Florida are expected 

 to be low in S. 



Some of the earliest reports of S deficiency in crops in Florida 

 were in the 1940 's and early 1950 's by Harris, Bledsoe, and coworkers 

 (Harris et al. , 1945, 1954; Bledsoe and Blaser, 1947). Harris et al . 

 (19 45) achieved a highly significant response to S by cotton on an 

 Arredondo loamy fine sand (Grossarenic Paleudult) . Two-week-old cotton 

 seedlings were severely stunted and yellow where no S was applied and 

 produced 70% of the dry matter of S-fertilized plants. At 6-weeks, 

 the deficient plants produced less than 20% of the dry matter of S- 

 fertilized plants. They also observed a response to S on a Norfolk 

 fine sand (Typic Paleudult) and suggested that S deficiency couid occur 

 in wide areas of Florida. 



