INFLUENCE OF SOIL LTPON YIELD. 



23 



centage of nitrogen relatively higher, and gives a grain of lighter 

 weight per bushel and smaller yield per acre. 



The fact that one variety of wheat is adapted to a hot, dry climate 

 and another to a cool, moist one does not mean that the former under- 

 goes as complete maturation as the latter, even though the grain is not 

 shriveled. This is shown by the fact that a variety of w^heat well 

 adapted to a hot, dry climate will, when planted in a cool, moist one, 

 immediately grow plumper and the kernel weight will increase, as 

 was the case in the experiment of taking Minnesota wheats to Maine. 



INFLUENCE OF SOIL UPON COMPOSITION AND YIELD. 



In considering the effect of the soil upon the wheat crop there will 

 naturally be included experiments designed to show the effect of 

 fertilizers upon the crops. It is, in fact, upon experiments with fer- 

 tilizers that we must depend for most of our information on this 

 subject. 



Experiments to ascertain the effect of fertilizers upon the composi- 

 tion of the w^heat kernel were conducted b}^ Law^es and Gilbert for a 

 period of years extending fro in 1845 to 1854." Plots of land in 

 Avhich wheat was grow n continually were treated annually as follows : 

 Unmanured, manured with ammoniacal fertilizer alone, and manured 

 Avith ammoniacal fertilizer and proportionate amounts of mineral 

 salts. In composition calculated to dry matter, the wheat on the 

 plots receiving ammoniacal fertilizer alone contained quite uniformly 

 a slightly larger amount of nitrogen than either of the other two. 

 The averages for the ten. years were as follows : 



There w^as practically no difference in the nitrogen content of the 

 straw^ From these experiments the authors quoted conclude that 

 there is no evidence that the nitrogen content of the wheat kernel 

 can be increased at pleasure by the use of nitrogenous manures. 



Ritthausen and Pott '' report an experiment in which plots of land 

 were manured (1) with superphosphate alone, (2) with nitrate alone, 

 (3) with a mixture of superphosphate and nitrate, and (4) w^ere left 



« On Some Points in the Composition of Wheat Grain, London, 1857. 

 &Landw. Vers. Stat., 16 (1873), pp. 384-399. 



