1<»()-).] PUBLIC DOCUMENT— No. :v.\. 151 



the twt) plots between which the plot under eonsideration 

 lies to which no nitrate was applied. On this basis, the 

 average increase due to application of 150 pounds of nitrate 

 of soda was 499 pounds ; the use of 200 pounds of nitrate 

 of soda gave an apparent increase of 297 pounds; while 

 the application of 250 pounds of nitrate of soda gave an 

 a})parent increase of 911 pounds. The weather during the 

 period of growth of the rowen crop was too dry for tlie 

 best resuhs. At the rates of increase shown, the applica- 

 tion would be hardly profitable. 



XI. — Variety Test, Potatoes. 

 During the past season we have carried out the second 

 year's trial of forty-nine different varieties of potatoes, 

 including practically all of those of recent origin advertised 

 in prominent seed catalogues up to the spring of 1903, as 

 well as tw^o or three old standard sorts for comparison. The 

 seed used this year was grown from the original stock of 

 each of the varieties on our own grounds in the season of 

 1903. The seed of all varieties was carefully preserved 

 during the winter under precisely similar conditions. In 

 preparation for planting, the tubers were treated with for- 

 malin for prevention of scab, in the customary manner. 

 After removal from the formalin solution, they were spread 

 in a thin layer in an airy room April 30, where they were 

 allowed to lie until the 17th of May, when the tubers were 

 cut into pieces of about two or three eyes each, and planted. 

 The soil used in this experiment is a medium loam. It pro- 

 duced a corn crop in the season of 1903, and mixed grass 

 and clover seeds were sown in the standing corn. Neither 

 grass nor clover had made much growth when the field was 

 plowed on May 3 in preparation for the potatoes. The field 

 received an application of barnyard manure at the rate of 

 41/2 cords per acre, and fertilizers at the following rates : — 



