470 NATURE AND PROPERTIES OP SOILS 



different period at the same place, determined the addition to 

 be less than .2 pound a month. Stewart, 1 at the University 

 of Illinois, reports the addition of sulfur as S0 3 over a period 

 of seven years as amounting to 9.4 pounds of S0 3 monthly to 

 the acre or 113 pounds yearly. 



The loss of sulfur expressed as S0 3 from the Cornell lysi- 

 meters, 2 due to cropping and drainage combined, amounted, 

 over a period of ten years, to 149.5 pounds from an acre 

 yearly from the rotation tanks. The addition of sulfur in the 

 rain-water at Ithaca amounts to about 65.4 pounds of SO s 

 each year. It is, therefore, safe to assume that rain-water will 

 not replace the sulfur removed by normal cropping and 

 leaching. It must be remembered, however, that in rational 

 soil management, sulfur is ret urned to the soil in green- 

 manures, crop residues and farm manures. Commercial fer- 

 tilizers are now very commonly used, especially acid phos- 

 phate, which is about one-half gypsum. At the Ohio Experi- 

 ment Station, 3 plats treated with sulfate bearing fertilizers 

 were found over a period of years to contain considerably 

 more sulfur than soils not so fertilized but cropped in a 

 similar manner. 



In the light of such data it seems that the sulfur problem 

 is not comparable with or as serious as the phosphorus prob- 

 lem of soil fertility. By the careful utilization of the normal 

 residues produced on the farm there seems little reason for 

 sulfur being a limiting factor in soil productivity, especially 

 if fertilizers carrying sulfur are used in connection with a 

 rational system of soil management. 



1 Stewart, R., Sulfur in Relation to Soil Fertility; 111. Agr. Exp. Sta., 

 Bui. 227, 1920. 



'Complete data on these lysimeters will be found in par. 163 of this 

 text. 



3 Ames, J. W., and Boltz, G. E., Sulfur in Relation to Soils and Crops; 

 Ohio Agr. Exp. Sta., Bui. 292, 1916. 



