32 



Maine Agricultural Experiment Station. 1919. 



No Potash Experiment with Potatoes. ipi^-ipi6-ipiy-ipi8. 

 Yield in Hundredweight Per Acre 





1915 1916 



1917 



1918 





Amount of Potash 



Series 1 



Series 2* 



Series 1 



Series 2 



Series 1 



Series 2 



Average 



None 



None + Salt 



3 per cent Potash 



6 per cent Potash 



7 per cent Potash 



182 



191 

 191 

 198 



172 

 193 

 254 

 254 

 244 



198t 



200f 

 193f 

 191t 

 226t 



131 



13fi 

 135 

 131 

 139 



140 

 144 

 150 

 157 

 160 



84t 

 89t 

 94+ 

 125+ 

 134+ 



123 

 130 

 128 

 137 

 134 



150 

 140 



172 

 174 

 175 



*In this series the potatoes followed potatoes. 1 Omitted from average. 



From the results of these 5 trials in 4 seasons on sod land 

 the following conclusions may be drawn : The addition of 300 

 pounds of common salt per acre made a small but uniform in- 

 crease in yield. Omitting the yields for 191 5 in which there 

 was no salt plot, the average yield for the plots without potash 

 or salt was 140 hundredweight and for the plots without pot-* 

 ash but with common salt added the yields averaged 151 hun- 

 dredweight. The addition of as little as 45 pounds (1500 pounds 

 of 3 per cent goods) per acre of potash uniformily increased 

 the yield of potatoes and profitably. On the Caribou loam of 

 Aroostook Farm soil nothing was gained by a larger applica- 

 tion. Good yields were obtained without any potash. From 

 the soil test experiment on Caribou loam on this farm it ap- 

 pears to be the case that nitrogen and not potash is the limit- 

 ing factor in potato production on this soil on this farm. "Pot- 

 ash hunger" did not manifest itself in either year in these trials. 



