442 ANNUAL REPORT OF THE Off. Doc. 



and, therefore, to raise wheat successfully, the soil should be in a 

 high state of cultivation, or should be peculiarly adapted for the 

 •ulture of wheat. The experiments of Loew and Gilbert illustrate 

 the weak feeding powers of wheat, especially in regard to nitrogen, 

 as the following table will show: 



No manure applied for 40 years, 14 bushels per acre. 



Mineral fertilizer alone for 32 years, 15| bushels per acre. 



Nitrogen fertilizer alone for 32 years, 23^ bushels per acre. 



Barnyard manure for 32 years, 32| bushels per acre. 



Minerals and nitrogen alone for 32 years, 36^ bushels per acre. 



Wheat, therefore, should be grown on soils especially adapted 

 and should be placed in such a position in the rotation when the 

 soil is in the highest state of cultivation to assist its weak feeding 

 powers. Barley belongs to the same clas;= of cereals, but differs 

 from wheat in that it has a stronger root development, can use 

 plant food as Liebig has shown in a less available form, which is true 

 of potash, nitrogen and phosphoric acid. This has been well illus- 

 trated in some of the Western states where .-heat has been grown 

 for years in succession, and no longer yields satisfactory crops, 

 whereas, barley gives excellent results. 



This is due to a condition of the soil produced by the long cultiva- 

 tion of wheat rendering the plant food less available, the soil more 

 porous, creating a condition to which barley can adapt itself better 

 than wheat, because of its stronger feeding powers. Barley, how- 

 ever, is greatly benefited by manuring, especially by those contain- 

 ing nitrogen, as experiments by Loew and Gilbert have shown: 



No manure for 34 years, averaged per acre 23J. 



No manure for 34 years, averaged per acre 17|^. 



Super-jjhosphate alone for 34 years, averaged per acre 23J. 



Mixed minerals for 34 years, averaged per acre 24^. 



Nitrogen alone for 34 years, averaged 30f . 



Nitrogen and super-phosphate for 34 years, averaged per acre 45. 



Barnyard manure for 34 years, averaged per acre 49^. 



Barley, like wheat, derives the greatest benefit from nitrogen, 

 showing that it has special difficulty in getting this element. The 

 feeding powers and habits of oats are such that they can obtain food 

 when it is less available than the barley, and they will thrive in an 

 acid or alkaline condition of soil where either wheat or barley 

 would perish. But nitrogenous fertilizers benefit them greatly, 

 even to such an extent as to double the yield. Corn seems to be 

 an exception to the general weakness of the cereal crops, because it 

 seems to able to feed on the nitrogen of the organic matter of the 

 soil as it passes through the stages of nitrification, but has especial 

 difficulty in getting phosphoric acid. Corn will thrive when the 

 fertility in the soil is in a crude condition, and will utilize a large 



