home; mixed fertilizers. 



141 



County to use 1000 to 1200 pounds per acre of such a fertilizer 

 as last named, which would furnish about two-thirds the 

 required nitrogen for a 300 bushel crop, three times as much 

 phosphoric acid and rather more than enough potash. 



In general the potato plant thrives best in a soil abundantly 

 supplied with all fertilizing elements. In the early stages of 

 growth nitrogen is particularly demanded, and hence a consider- 

 able part of the nitrogen should be in water soluble form, so that 

 it may be readily available early in the season. Later, when the 

 tubers are forming, there is special demand for phosphoric acid 

 and potash. 



The formula used by a number of farmers in Cumberland and 

 Aroostook Counties in 1904 at the rate of 900 to 1300 pounds 

 per acre, and giving a yield from 100 to 140 barrels (275 to 380 

 bushels) per acre was as follows: 



FORMULA (NO. i) FOR 300 BUSHELS POTATOES, USED IN I904. 

 SATISFACTORY WHERE THE SEASON WAS LONG ENOUGH TO 

 MATURE THE CROP. FOR ONE ACRE. 



Sd)3 



•rj O 



SB I 



Phosphoric 

 Acid. 



03 n 



03 O 



> a 



< I 



■a a 

 - I 



Tankage* 



Cotton seed meal . . 



Nitrate of soda 



Acid phosphate — 

 Sulphate of potash , 



500 

 200 

 100 

 400 

 200 



27.7 

 13.7 

 14.7 



36. 5f 



1,400 



Percentage composition 



Percentage composition as used in Aroostook 

 county* 



56.1 

 4.0 



4.3 



104.7 

 7.5 



7.4 



80.2 

 7.2 



71.0 



15S.4 

 11.3 



10.2 



5.S 



102.6- 

 7.3 



7.3 



*In the Aroostook county lots 420 pounds of a tankage with less phosphoric acid 

 and more potash was used, with a resulting higher percentage of nitrogen and 

 lower percentage of potash. 



tThis represents the amount of phosphoric acid that is "citrate soluble" as 

 found by chemical analysis, but it is not as speedily available to the growing 

 crop as that of acid phosphate. 



