50 MAINE AGRICULTUR.\L EXPERIMENT STATION. I915. 



The fertilizer used was high grade, carrying 4 per cent nitro- 

 gen, 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 high grade organic 

 nitrogen. The yields are based upon weighings and not upon 

 measure. The potatoes were clean, without adhering soil. 



In potato experiments at Highmoor Farm the Station had 

 found that when there was only a small amount of rainfall fol- 

 lowing the second application of fertilizer that apparently this 

 added fertilizer was not well utilized. This present season, how- 

 ever, at Aroostook Farm there was ample v/ater to dissolve and 

 render this plant food in all of the fertilizer available. It has 

 been estimated that it takes about six inches of water to suc- 

 cessfully grow a crop of potatoes. In the spring of 1914 the 

 ground was well filled Avith water. In May at Aroostook Farm 

 there was 2.74 inches of rainfall, and in June 4.8 inches, in July 

 2.23 inches and in August 2.35 inches, or a little more than 12 

 inches during these four months. 



On plots I and 4 on which 1000 pounds of the fertilizer were 

 applied broadcast and 500 pounds with the planter at the time 

 of planting, the yield was 121 and 127 barrels, making an average 

 of 124 barrels per acre. On plots 2 and 5, where 1500 pounds 

 of fertilizer were applied all in the drill at the time of planting, 

 the yields were 134 and 127 barrels, or an average of 130 barrels 

 for the two plots. The yields on plots 3 and 6, where the ferti- 

 lizer was applied 1000 pounds in the drill and 500 pounds with 

 the first cultivation, were the same as in plots i and 4, being 127 

 and 121 barrels with an average of 124 barrels per acre. 



In field experiments of this kind even if there had been 

 marked dififerences it w^ould not do to draw conclusions from a 

 single year's trial because there are so many things that come in 

 to modify the results of a field experiment even when the plots 

 are as large as these were. 



So far as a single year's test goes there is little to choose 

 between the three methods, although 6 barrels more per acre 

 were obtained where all of the fertilizer was applied in the drill 

 than in the two other methods. It is interesting to note. howcA-er, 

 that one of the plots in each method of treatment yielded at the 

 rate of 127 barrels to the acre. If those plots alone were selected 

 there would have been no difiference in yields in the experiment. 



