38 



The Bulletin 



Effect of Varying Quantities of Fertilizer on Yield. 



The tests in Table 5 were arranged to show the effect of increasing and 

 decreasing the normal fertilizer application on yields, the normal 

 (N P K) being 300 pounds of a mixture containing 7 per cent phosphoric 

 acid, 3 per cent nitrogen and 1% per cent potash. The applications 

 were at the rate of 150 pounds per acre 1/2 (IST P K) ; 300 pounds per 

 acre (N P K) ; 450 pounds per acre II/2 (N P K) ; 600 pounds per acre 

 2 (N P K) ; 750 pounds per acre 21/2 (N P K) ; and 900 pounds per 

 acre 3 (N P K). The results in all the fields show increased yields for 

 all the quantities of fertilizer. The amount varied from 150 pounds to 

 900 pounds per acre. 



As an average on the three fields for seven years, the increased ap- 

 plication of fertilizer gradually increased the yields. With corn this in- 

 crease was not enough to pay for the fertilizer when the grain alone 

 was considered, and the heaviest application gave the greatest loss. 

 When the stover was taken into consideration, the one and one-half and 

 two times applications gave small profits. In general the results indi- 



TABLE VI.— RESULTS' OF FERTILIZER EXPERIMENTS WITH CORN SHOWING THE EFFECT 



Results in "Old Field" 



Number 



of 



Plat 



82 



152 



1» 



2' 



6> 



33 



Fertilizer Application Per Acre 





^< 

 a o 



fPL, 



o 



Unfertilized - 0= 



34.6 Pounds 13% Blood at planting- HN= 



30.4 Pounds 14.8% Nitrate of Soda about July 1-}^N= 



Pounds 14% Acid Phosphate - P= 



Pounds 20% Manure Salt --K= 



Pounds 14.8% Nitrate of Soda at planting. .}^N= 

 Pounds 14.8% Nitrateof Soda about July 1 }^N= 



Pounds 14% Acid Phosphate. P= 



Pounds 20% Manure Salt K= 



Pounds 13% Blood at planting >^N= 



34:6 Pounds 13% Blood about July 1 HN= 



150 Pounds 14% Acid Phosphate P= 



22.5 Pounds 20% Manure Salt. K= 



Unfertilized 0= 



55.4 Pounds 13% Blood applied at planting 4-5N= 



12.2 Pounds 14.8% Nitrate of Soda applied at 



planting 1-5N= 



150 Pounds 14% Acid Phosphate P= 



22.5 Pounds 20% Manure Salt K= 



4.5 

 4.5 



150 

 22 

 30 

 30 



150 

 22 

 34 



4.5 

 4.5 



4.5 

 4.5 



7.2 

 1.8 



21 



21 



21 



21 



O 



o 

 Ah 



4.5 



4.5 



4.5 



4.5 



Yield in Bushels of 

 Shelled Corn Per Acre 



1903 1904 



23.9 



12.3 



17.5 



25.3 



21.3 



25.3 



29.9 



30.5 



26.6 



31.0 



25.6 



31.4 



Ave. 



26.4 



21.4 



22.1 



28.2 



23.5 



28.4 



