CHAPTER IV 



Soil Temperature 



FOR centuries farmers have observed that some soils 

 are seemingly better adapted than others to grow 

 certain kinds of crops. These observations naturally 

 have led to what is called "wheat soil," "barley soil," 

 "rye soil," etc. While these observations on the face 

 of them would lead one to think that some soils are 

 more adapted than others for crop growing, there is a 

 great deal of doubt as to their real merit because in the 

 light of present-day experiments crops have been grown 

 in pure sand which had been supplied with the plant 

 food elements and the amount of moisture necessary to 

 grow plants. 



Climatic conditions have much to do with crop grow- 

 ing, consequently, when one begins to study what crops 

 that soil is to produce, he must take into consideration 

 the climatic conditions as well as the soil. Naturally 

 then, if a farmer can supply a soil with conditions 

 equivalent to climate, he can, to the extent of that 

 ability, grow plants in any soil. 



The wheat and oat plants offer an interesting illus- 

 tration of this fact. Assuming that the proper fertility 

 is in the soil, whether it is sand or clay, climatic con- 

 ditions, that is, temperature and water, must determine 

 the growth. Up to the time of ear shooting wheat 

 needs wet, but not too warm weather; at flowering 



