816 STATE BOARD OF AGRICULTURE. 



to shade the ground then the creation of conditions (2), (3), and (4) 

 would be of practically no important benefit. 



Furthermore, by creating conditions (2), (3), and (4) the temperature 

 of the heavy types of the mineral soils could hardly be increased more 

 than 2°F; that of the peat, however, could be raised almost twice this 

 amount. The practical importance of this comparatively small increase 

 in average temperature, therefore, would depend upon the sensitiveness 

 of the germinating seed and growing plant upon the temperature and 

 upon the time of the growing season. 



Again, it must be remembered, that it is not only the soil temperature 

 that influences the growth of plants, but the air temperature as well. 

 Hence, if the air temperature is the same over a certain area then the in- 

 fluence of small variation of temperature that may exist in adjacent 

 difl'erent types of soil would be of lesser significance. 



Some of the intrinsic factors which man can modify to keep the soil 

 waiTii or protect it from extreme low temperature in the winter are: (1) 

 covering the soil with straw or any other material, and (2) heating the 

 soil. 



Man can regulate the soil temperature far easier, more successfully and 

 probably with far greater practical results during the cold part of the 

 year than at any other other time. 



