BULLETIN No. 162 MAY, 1915 



MASSACHISETTS 

 AGRICULTURAL EXPERIMENT STATION 



PHOSPHATES IN MASSACHUSETTS 

 AGRICULTURE 



IMPORTANCE, SELECTION AND USE 

 By Wm. P. BROOKS 



This bulletin shows that phosphoric acid is not relatively defi- 

 cient in Massachusetts soils, and that under the systems of 

 agriculture common in the State (which almost invariably include 

 the use of some phosphate) there is no reason to believe that it is 

 generally becoming more so. The general results of two series of 

 experiments comparing different phosphates, one extending over 

 twelve and the other over eighteen years, are presented. These 

 results indicate that the application of at least a moderate amount 

 of phosphate is usually profitable, and that the more soluble and 

 available materials give results much superior to those obtained 

 with the fine-ground rock phosphates. It is shown that the dis- 

 solved phosphates favor more rapid early growth, earlier and more 

 perfect maturity and larger yields than the rock phosphates, and 

 that the former are used with greater profit than the latter. 



Requests for bulletins should be addressed to the 



Agricultural Experiment Station, 



Amherst, Mass. 



