52 Maine Agricultural Experiment Station. 1919. 



The results for 191 7 were given in detail in Bulletin 269. 

 In 1918 the stand was even and other than the killing frost 

 when the plants were about 6 inches high and from which 

 they did not fully recover, the experiment was successful. 



The plots, Series C, 1918, arranged in their relations to 

 fertilizer used are shown in the following triangular diagram. 



The plots showing the average yields in 191 7 and 19 18, 

 arranged in their relation to the fertilizers used are shown in 

 the following triangular diagram. 



Diagram of Potato Soil Test Experiment ipiy and 1918. 

 Series A and C. 



The numbers above the * and connected by the - show the fertilizer 

 formula used each year and applied at the rate of 1200 pounds per acre. 

 The letters N, P and K indicate the parts of the triangle where am- 

 monia, available phosphoric acid and potash are respectively at their 

 maximum amounts. The numbers below the * give the average yields 

 per acre in hundredweights. 







N 









Highest Ammonia 









20-0-0 









16-4-0 



123 



16-0-4 







* 





* 





12-8-0 



148 



12-4-4 



146 



12-0-8 



* 





* 





* 



157 



8-12-0 



8-8-4 



154 



8-4-8 



143 



8-0-12 



152 155 140 158 



4-16-0 4-12-4 4-8-8 4-4-12 4-0-16 



142 128 165 156 127 



0-20-0 0-16-4 4 0-12-8 0-8-12 0-4-16 0-0-20 



95 113 108 93 89 115 



P K 



Highest Phos- 











Highest Pot- 



phoric Acid 











ash 



0-0-0 



0-0-0 



0-0-0 



0-0-0 



0-0-0 



0-0-0 



* 



* 



* 



* 



* 



* 





5-8-7 



4-8-10 



4-8 1 -8 



4 2 -8-8 



4 3 -8-8 





* 



* 



* 



* 



* 





129 



139 



145 



135 



141 



Phosphoric acid in form of floats. 2 Ammonia in form of dried 

 blood. 3 Ammonia in form of tankage. "Omitting this plot for 1917. 



