Maine Agricultural Experiment Station. 1917. 115 



creasing use of high grade organic nitrogen for food of ani- 

 mals, the price of tankage has been going higher and higher 

 year by year. It is, of course, desirable, if it can be done, that 

 as much as possible of this sulphate of ammonia, which is a. 

 comparatively cheap source of nitrogen, be used in Maine ferti- 

 lizers. 



Because of these facts, arrangements were made to begin 

 in 1914 a series of experiments to run over a period of several 

 years. The "base" which was used in these goods was made by 

 the wet process, whereby nitrogen from rather low grade goods 

 is made as available as from high grade goods. The available 

 phosphoric acid was furnished in the form of acid phosphate 

 and the potash in the form of sulphate of potassium. The fer- 

 tilizer was free from chlorides so as to preclude the 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 ammonia, as indi- 

 cated 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 of 

 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 of 

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



In each case the finished fertilizer analyzed 4 per cent ni- 

 trogen, 8 per cent available phosphoric acid and 7 per cent po- 

 tash. In each year the fertilizer has been applied in the planter 

 at the rate of 1500 pounds per acre. Other than the fertilizer 

 used the plots were planted, cultivated, sprayed and cared for in 

 all particulars alike. In each year duplicate plots each about 

 one-half acre in area have been grown with each mixture. 



The results for 1914 and 1915 are reported in detail in 

 Bulletin 246. The detailed results of the experiment for 1916 

 are given in the table which follows. 



