CHAPTER IV. 

 CULTIVATION OF WHEAT 



SOIL PREPARATION 



The cultivation of wheat is coeval with agriculture itself. No 

 land was alone the ground of Ceres where the human race 

 learned to plow and sow, nor was it the task of any one race 

 or nation to tutor mankind in the agricultural arts. How the 

 nations of antiquity tilled, sowed and reaped would be of great 

 interest, but the records which time has bequeathed to us are 

 all but silent upon these homely topics. 



Climatic Effects. The soil in nature is more uniformly cov- 

 ered with vegetation throughout the year than it is under 

 cultivation. Dark, exposed soil absorbs more heat than soil 

 covered with vegetation. Thus cultivation is supposed to mod- 

 erate climate and there is a widely prevalent opinion that it 

 also lessens frosts, humidity and rainfall. 



Plant and Soil Effects. Soil alterations of the highest im- 

 portance are made by means of tillage, fertilizing and irriga- 

 tion. The resulting variations in wheat are quantitative rather 

 than qualitative, except in the case of irrigation, which is 

 practiced on a comparatively small part of the wheat area. 

 This process and that of fertilizing are discussed in later chap- 

 ters. Cultivation, as here used, refers only to the mechanical 

 operations connected with raising wheat in the natural environ- 

 ment treated in the previous chapter. It renders this natural 

 environment artificial to the degree in which it alters the me- 

 chanical arrangement of the soil in nature and eliminates from 

 the competition of life other species of plants which would 

 naturally compete with wheat in the struggle for obtaining the 

 sustenance held by soil and atmosphere. This sets the 

 wheat plant free from many natural conditions which tend to 

 destroy unfit variations and to force wheat to assume one 

 type. Thus cultivation, while it has no direct influence in in- 

 creasing variation, by removing conditions which exert a se- 

 lective influence, is indirectly the means by which a greater 



