BULLETIN No. 176. 



DEPARTMENT OF CHEMISTRY. 



THE CAUSE OF THE INJURIOUS EFFECT OF 



SULFATE OF AMMONIA WHEN USED 



AS A FERTILIZER.^ 



BY R. W. RUPRECHT AND F. W. MORSE. 



Part I. — Chemical Investigations. 



In a previous report ^ there has been described how the continued use 

 of sulfate of ammonia on the experiment plots called "Field A" caused 

 the removal of lime in the drainage waters in the form of calcium sulfate, 

 and when lime was not present in sufficient quantity there were formed 

 noticeable amounts of aluminium sulfate and iron sulfate, but that no 

 accumulation of free acid could be found. 



Since comparatively little material had been published on the forma- 

 tion of salts of aluminium ard iron in soils, it was considered advisable 

 to continue the investigations, and as the work progressed it was found 

 that soluble manganese salts were also present in some of the soils to 

 which sulfate of ammonia had been applied. 



The present bulletin is a report of our investigations into the relations 

 between sulfate of ammonia and salts of aluminium, iron and manganese, 

 and the quantities of these salts which will injure clover seedUngs. 



Soils from plots 1, 6, 7 and 8 of Field A were used to determine how 

 freely ammonium sulfate solutions would extract manganese from them. 

 The soils have been fully described in Bulletin No. 185, but for con- 

 venience the fertilizers used on these four plots mil be described here. 



Each plot received dissolved boneblack at the rate of 500 pounds per 

 acre, and muriate of potash 250 pounds per acre. Plot 1 received 300 

 pounds of nitrate of soda per acre; plots 6 and 8 received 225 pounds of 



1 The work reported in this bulletin, together with the material published in Buls. Nos. 161 

 and 165, was submitted by Mr. Ruprecht to the faculty of the graduate school of the Massa- 

 chusetts Agricultural College in part fulfillment of the requirements for the degree of doctor of 

 philosophy. 



2 Bui. No. 165, "The Effect of Sulfate of Ammonia on Soil." 



