400 



ANNUAL. REPORT OF THE 



Off. Doc. 



It was applied in three ditfereiit amounts, 24, 48 and 72 pounds per 

 acre respectively. 



The following table gives the average value of the products from 

 twenty-five years' rotations when nitrogen was applied in the differ- 

 ent form and different amounts indicated in the table in connection 

 with phosphoric acid and potash, the latter always being applied in 

 the same amounts. 



DIFFERENT FORMS AND AMOUNTS OF NITROGEN. 



Alternate Tears. 



c 



§ 



a 

 o 



CO 



Dried blood 



Nitrate of soda 



Sulphate of ammonia, 



$92 79 

 94 22 

 84 45 



The analysis of this table shows clearly that nitrate of soda has, 

 almost without exception, given better results than either dried 

 blood or sulphate of ammonia. It will be noted that sulphate of 

 ammonia in the largest amount has given the poorest result. Dur- 

 ing the first ten years of the experiment the plats thus treated gave 

 the highest yields, but since that time the injurious effect of the 

 sulphate of ammonia when applied continuously in large amounts 

 has become very marked. Special investigations have shown that 

 the lime requirements of plats treated with sulphate of ammonia is 

 very much greater than those treated with nitrate of soda. The in- 

 jurious effect of this acid condition of the soil due'to the contlnnnna 

 use of sulphate of ammonia has been more marked upon the corn 

 and the clover than upon the wheat, oats or timothy. 



COMMERCIAL. FERTILIZERS IN COMPARISON WITH STABLE MANURE. 



It has been possible during twenty-five years to maintain the crop 

 producing capacity of this soil without the use of any stable man- 

 ure. When the yields of the three plats of each tier receiving 24, 

 48 and 72 pounds of nitrogen in connection with 48 pounds of phos- 

 phoric acid and 100 pounds of potash are averaged and compared 

 with four plats receiving six tons (two plats), eight tons and ten 

 ^ons of yard manure, it is found that the yield has been slightly 

 greater where commercial fertilizers have been used for every five 

 year period except one, as shown in the chart. 



Without the addition of any organic matter to the soil during 

 twenty-five years, except the roots and stubble of the crops raised, 

 the fertility of the soil has been fully maintained. Tlie table shows 

 the average value of the products twenty-five four-year rotations, 

 the cost of two applications of fertilizer and the value of the in- 

 crease during the rotation over the cost of the fertilizer. 



