l8 MAINE AGRICULTURAL EXPERIMENT STATION.' I916. 



Yields per acre Obtained in No Potash Experiment with 

 Potatoes — 191 5. 



Plot No. 



Amount of Potash. 



Merchantable . 



Bbls. 



Bush. 



Culls. 



Bbls. 



Bush. 



137 

 150 



None . 

 None . 



138 

 151 

 Average.. 



139 

 152 



Average.. 



140 

 153 



Average.. 



2 per cent . 

 2 per cent . 



5 per cent. 

 5 per cent. 



per cent . 

 per cent . 



107 

 112 

 110 



119 

 114 



116 



110 

 123 



lie 

 111 



130 



120 



295 

 309 



302 



327 

 313 



304 

 337 



304 



358 

 331 



11 

 17 

 14 



17 

 18 



17 



14 

 12 

 14 



14 

 14 



14' 



With the exception of the yield on plot 138, which is unex- 

 plainably high, the yields are consistent. In the first series 

 there is apparently no effect from the lack of potash. The 

 yields are about no barrels. In the second series the larger 

 amounts of potash (5 per cent and 8 per cent) have very 

 appreciable effects upon the yield. The increase is undoubtedly 

 large enough to be significant and to indicate that potash may 

 be expected to increase the yield of potatoes in Aroostook 

 County. 



On the other hand, no barrels (302 bushels) per acre 

 is a good yield — considerably above the usual average and 

 ready double the average in the County in 191 5. So far as the 

 results of this one year are concerned, they indicate that a 

 profitable yield of potatoes can be obtained on Aroostook soils 

 without the addition of potash for at least one year. In a few 

 farmers' trials made by the various fertilizer companies, m 

 which no exact records were made, satisfactory results were 

 obtained without the use of potash by all the growers from 

 whom the station has heard. It is planned to repeat this ex- 

 periment in 1916 and add to it a similar experiment on oats. 



The kind of fertilizers for 1916 is discussed in a circular on 

 "Growing Crops Without Potash in 1916" which will be sent 

 to any citizen of Maine on application. 



