CONTROL SERIES. BULLETIN NO. 4. DECEMBER, 1915. 



MASSACHUSETTS 



AGRICULTURAL EXPERIMENT 



STATION. 



INSPECTION OF 



Commercial Fertilizers 



BY 



H. D. HASKINS, L. S. WALKER, C. P. JONES and W. S. FROST. 



This bulletin gives a detailed report of the fertilizer inspection 

 for 1915. It states the number of fertilizers inspected, gives trade 

 values of fertilizer ingredients, provides a summary showing average 

 composition of unmixed fertilizing material as well as pound cost of 

 each element of plant food furnished. Special attention is called 

 to commercial shortages existing in both unmixed fertiUzing materials 

 and mixed goods. Particular emphasis is laid upon the economy of 

 purchasing only high grade fertilizers. A summary table shows the 

 general standing of each manufacturer's brands. A discussion is 

 made of the quality of plant food found present in the mixed goods. 

 A summary table shows the general quality of nitrogen found in each 

 manufacturer's product. Mention is made of the number and na- 

 ture of the lime products analyzed. A brief explanation of a vegeta- 

 tion experiment is made to show the efficiency of the alkaline per- 

 manganate method as an indication of the activity of water insoluble 

 organic nitrogen. Tables of analyses give the detailed composition 

 of all fertihzers and lime products sold in the state. Commercial 

 valuations of the plant food in all fertilizing materials, calculated 

 from the table of trade values, are pubUshed, and for the lime com- 

 pounds, the actual cost of 100 pounds of calcium and magnesium 

 oxide is given in each case. 



Requests for bulletins should be addressed to the 



AGRICULTURAL EXPERIMENT STATION, 



AMHERST, MASS. 



