470 NATURE AND PROPERTIES OF SOILS 



different period at the same place, determined the addition to 

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

 of Illinois, reports the addition of snlfur as SO3 over a period 

 of seven years as amounting to 9.4 ponnds of SO3 monthly to 

 the aere or 113 pounds yearly. 



The loss of sulfur expressed as SO3 from the Cornell lysi- 

 meters,^ 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 SO3 

 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 returned 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,^ 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. 



* Stewart, B., Sulfur m Belation to Soil Fertility; 111. Agr. Exp. Sta,, 

 Bui. 227, 1920. 



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

 text. 



* Ames, J. W., and Boltz, Gr. E., Sulfur in BelatioTi to Soils and Crops; 

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



