FIELD EXPERIMENTS IN 1915. 23 



possibility of the formation of poisonous ammonium chloride. 

 The base carried approximately one-third of the nitrogen that 

 went into the formula. The remainder of the nitrogen was 

 furnished in the form of nitrate of soda and sulphate of ammo- 

 nia, as indicated in the following plan: 



Plot 1. Basal mixture and 2-3 of the nitrogen in form of 

 nitrate of soda. 



Plot 2. Basal mixture and 2-3 of the nitrogen in form of 

 sulphate of ammonia. 



Plot 3. Basal mixture and 1-3 of the nitrogen in form 01 

 nitrate of soda and 1-3 in form of sulphate of ammonia. 



Plot 4. Basal mixture and 1-3 of the nitrogen in form of 

 high grade organic and 1-3 in form of nitrate of soda. 



Plot 5. Basal mixture and 1-3 of the nitrogen in form ni 

 high grade organic and 1-3 in form of sulphate of ammonia. 



The 1914 Experiment. 



There was about an acre in each plot. The Lowell Strain 

 of Green Mountain potato was used for seed in 1914. The 

 fertilizer was applied at the rate of 1500 pounds per acre, and 

 supplied about 60 pounds of nitrogen, 120 pounds of available 

 phosphoric acid and 105 pounds of water soluble potash per 

 acre. Other than the fertilizer used the plots were planted, 

 cultivated, sprayed and cared for in all particulars alike. The 

 fertilizers used in 1914 were not analyzed at the Station. 



The plots were planted on the following dates : Plot 87, 

 May 29 ; Plots 88 and 89, May 30 ; Plot 90, partly May 30 and 

 finished June 1 ; Plot 91, June 1. They were harvested as 

 follows : Plot 87, October 1 ; Plot 88, September 30 ; Plot 80, 

 September 29 ; Plot 90, partly on September 28 and remainder 

 on September 29; Plot 91, September 28. 



May and June were rather cool months and hence would he 

 favorable to the nitrate of soda. The mean temperature for 

 May was 53.2 degrees, for June 56.0 degrees, July 63.5 

 degrees, August 60.1 degrees, and September 55.8 degrees. 

 There were several cold nights with frosts in June. May 4 

 the thermometer went to 25 degrees, May 5 to 32 degrees, 

 June 9 to 30 degrees, and June 28 to 31 degrees, and on this 

 latter date there was quite a heavy frost so that it injured 



