CULTURE OF WHEAT 75 



The wheat is sown after the renxoval of the potatoes without 

 plowing. The residual effect of the fertilizers combined with 

 the influence of the tillage given the potatoes usually results in 

 increased wheat production. 



120. Carriers of Fertilizing Constituents. — The results of 

 many experiments with various forms of phosphatic fertilizers 

 seem to indicate clearly that when these are applied to wheat 

 the carrier or source of the phosphoric acid, whether raw bone 

 meal, undissolved rock phosphate, basic slag, acid phosphate, 

 or tankage, does not materially affect the yield provided the 

 material is finely ground. Nitrate of soda has been found to be 

 the most effective carrier of nitrogen, although the difference in 

 the effectiveness of different carriers of nitrogen is not great 

 when applied to wheat 



121. Relative Importance of Fertilizing Constituents. — WTiile 



field experiments indicate that the relative miportance of 

 fertilizing constituents depends upon the soil, throughout the 

 drift area of the United States, phosphoric acid is the only ferti- 

 lizing ingredient which, when applied singly, has been found 

 generally to increase the yield of wheat. The increase in the 

 yield of straw has usually been greater than the increase 

 in .^Tain. (z,7,) For this reason, the increased appearance of 

 the crop is generally greater than the increased yield of grain. 

 The influence of fertilizers upon the seeding of timothy and 

 clovv^r when it accompanies the seeding of the wheat is often de 

 cide« 'ly favorable. Neither nitrogen nor potash when used alone 

 prod' ces generally any marked influence on the yield, but both, 

 and . <itrogen especially when applied with phosphoric acid in 

 prope • proportions, appear to exert a favorable influence. The 

 Ohio ' Station has found that a complete fertilizer, containing all 

 three constituents, has produced a much larger total increase 

 than tl e sum of the increase produced by the constituents used 

 separate 'v.- The same idea is expressed in the results obtained 

 1 Ohio BiJ. no (1899). P- 68. 



