The Bulletin. 21 



Phosphoric Acid and Potash, P K (Plats 12^ and 7). Phosphoric 

 acid and potash combined produced increased yields of hay in all 

 five years of the tests on the plats in both fields over the imfertilized 

 plats, the annual average for the first four years in Pield C being 

 840 pounds per acre (120 pounds more than phosphoric acid alone j, 

 and for the fifth year (1908) in Field A 1,900 pounds (200 pounds 

 more than phosphoric acid alone), valued over the cost of fertilizer 

 respectively at $4.50 and $12.45 per acre. 



Phosphoric Acid, Potash and Nitrogen, J^ P K (Plats 6 and 8). 

 These three materials combined in a complete fertilizer gave in- 

 creased yields in all of the tests on all the plats, the annual average 

 for the four years in Field C being 962 pounds of bay and for the 

 fifth year in Field A 1,800 pounds. The net value of the increase 

 (value over the cost of fertilizer) was $4.72 in Field C and $11.01 

 in Field A, or 52 cents more than phosphoric acid in Field C and 54 

 cents less in Field A. 



For the production of hay these experiments, as a whole, show that 

 phosphoric acid (acid phosphate) produced the increased yields and 

 that nitrogen and potash had very little effect, and in a number of 

 tests none at all. 



