Transformation of Sulfur 



231 



The removal of sulfiu- b\- farm crops may be far greater than has 

 usualK' been assumed; it may be entirely out of proportion to the 

 reserve of this element in the soil. It has been suggested that the 

 depletion of sulfur ma\ , in time, have an important effect on soil 

 fertility. The annual loss of sulfur from uulimed soil througli crop- 



10,800 



9600 



8400 



7200 



>- '-> 6000 



4800 - 



3600 



2400 - 



1200 











35 



5 10 15 20 25 30 



Period of incubation in weeks 



Fig. 94. Course of accumulation of citrate-soluble P2O5 and SO4 in composts of 

 soil, rock phosphate, and sulfur (from Lipman, McLean, and Lint). 



ping and drainage has been reported to amount to 44 pounds per 

 acre. This loss was increased by applications of lime. One-half to 

 two-thirds of the sulfur applied to the soil in the form of potassium 

 sulfate was found to be removed in the drainage water. 



Sulfur is added or finds its way into the soil in a number of dif- 

 ferent forms: (fl) in certain organic compounds, which form con- 

 stituent parts of the plant and animal residues added to or left on 

 the soil; (Z?) as elementary sulfur, which is usually added to the soil 

 as a fertilizer or which is continuously brought down in the rain 



