.|0M£ OFAGBIQinmffiSEARCH 



Vol. XVII Washington, D. C, June i6, 1919 No. 3 



RELATION OF SULPHATES TO PLANT GROWTH AND 



COMPOSITION 



By H. G. Miller, 

 Assistant Chemist, Oregon Agricultural Experiment Station 



HISTORICAL REVIEW 



The oxidation of sulphur in the soil and the relation of the products 

 formed is plant growth, bacterial development and activity, and to the 

 release of other forms of plant food have been reported upon by many 

 investigators. In reviewing the work, many of the writers have reported 

 beneficial results from the use of sulphur fertilizers, especially with those 

 plants high in protein and other sulphur-containing compounds. Various 

 views are given as to how sulphur functions in producing these increased 

 yields. Analysis of soils reported by Hart and Peterson (11),^ Shedd 

 (22, 23) , Brown and Kellogg (7) , and Swanson and Miller {26) , show a lower 

 sulphur content in the cultivated soil as compared to the phosphorus, 

 while many of the cultivated plants show a larger content of sulphur 

 than phosphorus. These results indicate that sulphur v/ould become a 

 limiting factor before phosphorus. 



It is generally concluded that sulphur to be available for plant food 

 must be in the ^Iphate form, so that a soil having a high sulphur 

 content may not necessarily supply enough sulphate sulphur for maxi- 

 mum growth. Brown and Kellogg (6) have shown that different soils 

 have unlike sulphofying powers and some of the factors influencing the 

 change of elemental sulphur and sulphides to sulphate form. In 

 lysimeter experiments at Cornell, Lyon and Bizzell (77) report that 

 the sulphate sulphur in the drainage water was from three to six times 

 as great as in the crops and the sulphur content of the drainage water 

 from the unplanted soil was about equal to the sulphur content of the 

 crop and drainage water from the planted soil. Swanson and Miller (26) 

 conclude from an investigation on sulphur in Kansas soils that — 



the loss in sulphur due to the amount taken up by the crop is insignificant as compared 

 with the total amount which has disappeared from the soil. This means that sulpho- 

 fication has been in excess of the needs of the crop, and the sulphates produced have 

 been leached out of the ground. 



' Reference is made by number (italic) to "Literature cited," pp. 100-102. 



Journal of Agricultural Research, (87) Vol. XVII, No. 3 



Washington, D. C. June 16, 1919 



rw Key No. Oreg.-4 



