field experiments in i915. 19 



Method of Application of Fertilizer upon Potatoes at 

 Aroostook Farm. 



It has always been more or less customary in growing pota- 

 toes in Maine to apply the fertilizer in the drill or hill at the 

 time of planting. This was largely the practice when farm 

 manures were used in connection with potato growing and has 

 been followed with commercial fertilizers. Although now, 

 when farm manures are used in connection with potatoes they 

 are more likely to be applied broadcast and a smaller amount 

 of fertilizer applied in the drill. There was little question in 

 the minds of practical growers that when 500 to 1000 pounds 

 of fertilizer were applied per acre that it was to the best 

 advantage to apply it in the drill. With the increase up to 

 1,500 to 2,000 pounds per acre the question has arisen whether 

 it may not be advisable to apply the fertilizer at different 

 times. This led the Station to undertake a series of trials at 

 Aroostook Farm. 



In 1914 an experiment was started to extend over a period 

 of years for the purpose of testing the method of applying 

 fertilizer. Something over acre plots were used. Three plots 

 were used in the experiment in 1914. To one plot all of the 

 fertilizer was applied in the planter at planting. To another 

 plot 1,000 pounds of fertilizer was applied at planting 'and 500 

 pounds when the potatoes were up. And to a third plot 1,000 

 pounds was applied broadcast before planting and 500 pounds 

 in the planter at planting. The Lowell Strain of Green Moun- 

 tain potatoes was used for seed. The crop was well cultivated 

 and sprayed. 



The experiment was repeated in 191 5 and a plot was added 

 to which all of the fertilizer was applied broadcast before 

 planting. Through a misunderstanding the plot to which 1,000 

 pounds were added before planting did not have the other 

 500 pounds applied until the potatoes were up. Plots 133 and 

 134 were planted to Norcross. Lowell Strain Green Mountain 

 seed was used in the other plots. The yields from these two 

 varieties at Aroostook Farm have been practically identical. 



The fertilizer used each year was high grade carrying 4 

 per cent nitrogen, 8 per cent of available phosphoric acid and 

 7 per cent of water soluble potash. One-third of the nitrogen 

 was in the form of nitrate of soda, and the remainder was 



