MANURES AND FERTILIZERS. 63 



on the lighter soils of the State, fertilizers con- 

 taining a large proportion of potash are needed 

 to give the best results," while fertilizers with 

 relatively large proportions of phosphoric acid 

 produce the best results on heavy, clayey soils.* 



At the Massachusetts State experiment sta- 

 tion for some years a series of 10 plats of one- 

 tenth acre each in size have been grown to 

 corn and treated with one or two special arti- 

 cles of plant food, or else left unmanured. In 

 1888 those plats receiving a dressing in which 

 potash was the dominant ingredient gave ma- 

 terially increased yields of grain over the nitro- 

 gen plats, though a combination of 97 lbs. of 

 sulphate of potash and inagnesia and 100 lbs. 

 of dissolved boneblack gave the best yield. 



In experiments conducted over the State of 

 Massachusetts in 10 different counties, by Prof. 

 W. P. Brooks of the agricultural college, while 

 it was shown that soils differ widely in their 

 requirements, it was also demonstrated that 

 potash more often proves beneficial or much 

 more largely beneficial than either nitrogen or 

 phosphoric acid.f Potash as a rule most largely 

 increases the yield of both grain and stover, 

 but its effect upon stover production is greater 

 than upon grain production. 



* Storrs' agricultural experiment station. Report of 1892, 

 p. 67, 

 t Experiment Station Record, III, p. 165. 



