338 



Bulletin 179. 



* Mr. Wilbur furnished his own fertihzers. 



General results of the field experiments.— A study of all 

 the experiments for three years recorded shows that of the three 

 plant-foods when used alone, nitrogen gave the largest increased 

 yield in 26 experiments, phosphoric acid in 58 experiments and 

 potash in 36 experiments. This would seem to indicate that when 

 one plant-food is used alone, phosphoric acid will in most cases give 

 the best results. "When a mixture of two plant-foods was applied, 

 nitrogen and potash gave best results in 2-i experiments, phosphoric 

 acid and potash in 48 experiments, and nitrogen and phosphoric acid 

 in 52 experiments. A comparison of a complete fertilizer and stable 

 manure shows in 38 experiments the complete fertilizer gave better 

 results, while in 54 cases stable manure produced the larger crops. 

 These good results accompanying the use of stable manure may not 

 be due so much to the plant-food it contains as to an improvement 

 in the physical conditions of the soil. 



In only 40 cases out of a total of 126 recorded, did the complete 

 fertilizer, a mixture of nitrate of soda, phosphate and muriate of 

 potash, give better results than fertilizers containing one or two of 

 the plant-foods. 



These results tend to show that more often it is some especially 

 prepared rather than a complete fertilizer that a soil requires, and 



