COMMERCIAL FERTILIZER MATERIALS 467 



flowers of sulfur to a soil at the rate of 23 parts per million 

 of soil. He obtained increased growth in all treated soils on 

 which carrots, beans, celery, lettuce, sorrel, chicory, potatoes, 

 onions, and spinach were grown, the weights of the crops on 

 the treated soil being from 10 to 40 per cent, greater than those 

 on the untreated soil. On soils that had been sterilized before 

 applying sulfur, the effect was less marked, from which he 

 concludes that the beneficial effects were due to the influence 

 of the sulfur on the micro-organisms of the soil. There may 

 be some question, however, whether this conclusion is justi- 

 fiable. Sulfur was found by Boullanger and Dugardin * to 

 favor ammonification in soils. Beneficial effects from the use 

 of free sulfur have also been obtained by Demelon, 2 and by 

 Bernhard, 3 while von Feilitzen 4 found it to be ineffective as 

 a fertilizer. 



In this country, Shedd 5 of Kentucky obtained increases in 

 tobacco yield with sulfur. Perhaps the most marked results 

 with sulfur are reported by Reimer and Tartar 6 from Oregon. 

 Alfalfa and clover yields were increased from 50 to 100 per 

 cent. 



That free sulfur may, under certain conditions, exert a ben- 

 eficial influence on plant growth must be conceded, but that 

 the action is a direct nutritive one remains to be proven. 

 Free sulfur is insoluble and cannot be absorbed as such by 

 plants. It readily undergoes oxidation, however, producing 

 the sulfate, as already explained under sulfofication. As such 



1 Boullanger, E., and Dugardin, M., Mecanisme de V action fertilisante 

 du soufre; Compt. Eend. Acad. Sci. Paris, T. 155, pp. 327-329, 1912. 



2 Demelon, A., Sur V action fertilisante du soufre; Compt. Eend. Acad. 

 Sci. Paris, T. 154, pp. 524-526, 1912. 



3 Bernhard, A., Versuche iiber dis Wirkung des Schwefels als Dung im 

 Jahre 1911; Deutsche Landw. Presse., Band 39, S. 275, 1912. 



4 von Feilitzen, H. } tiber die Verwendung der Schwefelblute zur Be- 

 Tcampfung des Kartoffelschorfes und als indirktes Dungemittel; Fuhling's 

 Landw. Zeit., Band 62, Seite 7, 1913. 



6 Shedd, O. M., The Belation of Sulfur to Soil Fertility : Ky. Agr. Exp. 

 Sta., Bui. 188, 1914. 



"Eeimer, F. C, and Tartar, H. 

 in Southern Oregon; Ore. Agr. Exp. Sta.. Bui, 163 f 1919. 



