26 MAINE AGRICULTURAL EXPERIMENT STATION. I916. 



The mean temperature for May, 191 5 was 49.5 degrees, for 

 June 60.6 degrees, July 64.1 degrees, and August 61.8 degrees. 

 During June the thermometer did not go below 36 after the 

 second day and 45 was the lowest the thermometer went in 

 July. The rainfall for May was 4.05 inches, June 1.95 inches, 

 July 3.40 inches and for August 3.50 inches, making a total 

 of 12.90 inches during the growing months of 1915. 



In 19 1 4 the sulphate of ammonia gave smaller yields than 

 the nitrate of soda plots. In 191 5 the sulphate of ammonia 

 plots of the first series gave larger yields than the nitrate of 

 soda plots and in the second series practically the same yields 

 were obtained irrespective of whether the nitrogen was as 

 nitrate or ammonia. June, 1914, was 4 degrees colder than 

 June, 1915, and there were quite hard frosts up to the end of 

 the month. This gave a poorer chance for the nitrifying organ- 

 isms to render the sulphate of ammonia available. This may 

 account for the reduced yields from the sulphate of ammonia 

 in 1914. Plots 128 to 131 in 1915 were planted May 18. May 

 19 there was a rainfall of one and a half inches. While sul- 

 phate of ammonia is as easily dissolved in water as is nitrate 

 of soda, it does not leach out of soil nearly as fast. It would 

 seem, comparing the results from the first series with the 

 duplicate series, that the heavy rain of the 19th carried off 

 much of the nitrate of soda which reduced the yield because 

 of the lack of available nitrogen thus brought about. The 

 higher temperature (average of 4 degrees) of June 19 15 over 

 1914 seems to explain the yields from the duplicate plots being 

 practically the same with nitrate of soda as with sulphate of 

 ammonia. 



The average yields from the different test plots for the two 

 years are given in the table on the page that follows. 



It will be noted that for the two years the sulphate of 

 ammonia plots have somewhat larger yields than those ob- 

 tained from the nitrate of soda plots. The organic nitrogen 

 does not appear to be as completely available as either that of 

 the nitrate of soda or the sulphate of ammonia. This is in 

 accord with earlier trials made at Houlton where the organic 

 nitrogen seemed to delay the maturing of the crop, thereby 

 decreasing the yield. Experiments of this kind can give con- 

 clusive results only after a number of years trials. This ex- 

 periment is to be repeated in 1916. 



