236 Journal of Agricultural Research voi. v.no.6 



that ill sterilized soil the addition of elemental sulphur had no effect in 

 increasing plant growth, confirming their idea that elemental sulphur 

 acted through some influence on the soil flora. Demolon (2) believes 

 that sulphur not only acts by stimulating the soil flora but, in addition, 

 acts as a source of needed sulphur after it has been oxidized in the soil. 

 He showed conclusively that flowers of sulphur would gradually oxidize 

 to sulphates in the soil, a statement which w^e have confirmed and which 

 likewise has been shown by Lint (8) to be true. The fact that elemental 

 sulphur is oxidized in the soil probably has direct bearing on the necessity 

 for the use or presence of adequate quantities of lime or other basic 

 material in a soil receiving this treatment. This may not apply to 

 all. crops, but might properly explain the results secured by Wheeler, 

 Hartweil, and Moore (16), who showed that there was injury to cereals 

 following the application of elemental sulphur for the prevention of 

 potato scab, unless a considerable quantity of lime had been used in the 

 soil. From the South Oregon Experiment Station, Reimer (10) reported 

 large increases in the yield of alfalfa by the direct use of elemental 

 sulphur. Whether these experiments were conducted on soils of high 

 basicity has not been reported. 



The possibility of injury to the crop by partial oxidation of the ele- 

 mental sulphur to sulphite must always be kept in mind. Thalau (15) 

 has shown that sulphites of ammonium and calcium are toxic to plants 

 in dilute solution, but probably are not so toxic in the soil itself. The 

 fate of the elemental sulphur introduced into a soil will ultimately be 

 its oxidation to a sulphate, but the formation of intermediate compounds 

 and their toxic effect may account for the contradictory results that 

 have been recorded from its use. For example, Janicaud, Hiltner, and 

 Gronover (7) report deleterious effects with tomatoes from the use of 

 elemental sulphur, and some of the results of Sherbakoff (14) in the 

 treatment of potatoes for scab are of a similar order. Consequently, 

 the attempted introduction of elemental sulphur as a source of sulphur 

 in plant nutrition should, in our judgment, be viewed with caution. 



The basis for this statement will be amplified in the following report 

 of experimental work. After this manuscript had been prepared, the 

 work of Shedd (13), of the Kentucky Agricultural, Experiment Station, 

 was made public. In this work use was made of a number of sulphates 

 and sulphids, and of elemental sulphur. Good results from the use of 

 a number of these materials are reported. Elemental sulphur and gyp- 

 sum were helpful to tobacco, and elemental sulphur was materially 

 beneficial to turnips on the soil investigated. Clover on this soil was 

 not helped by sulphur-containing fertilizers, with the exception of a 

 benefit from the use of potassium sulphate. Other plants, such as mus- 

 tard, cabbage, and radish, showed increased growth with sulphur- 

 containing materials. 



