128 MASS. EXPERIMENT STATION BULLETIN 212. 



the kind of crop than by the type of soil on which it is grown. Dr. Brooks 

 presented this idea in liis summarization of these experiments pubhshed 

 in Bulletin No. 58 above cited, and was one of the first, if not the first, of 

 the fertility workers of the country to observe this fact. Results secured 

 during the score of years which has elapsed since the observation was first 

 made have confirmed the conclusion in abundant measure. 



The South Soil Test. 



This test is on a soil classified in the soil survey of the Connecticut 

 Valley as a Merrimac coarse sandy loam. The field is practically level, 

 and had been in grass without manure for five years previous to the laying 

 out of the test. Earlier still, for an unknown number of years, it had been 

 in pasture. 



Cropping System. 



The original plan was apparently that of a five-year rotation, consist- 

 ing of two years of corn, then a grain crop, followed by two years of grass 

 and clover. This plan, however, was not followed consistently, although, 

 in the thirty years of which we have full record, thirteen corn crops were 

 grown. A complete list of crops as grown year by year is contained in 

 Table I of the Appendix. 



Fertilizer Treatment. ' 



The fertilizer treatment is shown in the follo\\dng schedule: — 



