326 SOILS: PROPERTIES AND MANAGEMENT 



moisture that optimum conditions as far as the plant is 

 concerned may be obtained, should have no fear of a 

 poor utilization of heat. 



The increase of soil humus, of course, may act directly 

 in heat control by darkening the color and increasing 

 absorption. A soil mulch, being dry, not only checks 

 evaporation but lowers radiation while increasing absorp- 

 tion. Any methods of handling the land which tend to 

 better the physical condition of the soil and increase its 

 tilth tend also toward a proper heat control at the same 

 time. The whole question may be summarized by say- 

 ing that if a farmer adopts a proper system of moisture 

 control and at the same time employs methods that tend 

 always toward a better physical condition of the soil, 

 the problem of control of soil heat will be automatically 

 solved. He will then have brought about the best condi- 

 tions for heat absorption and will have facilitated conduc- 

 tion and convection, while at the same time retarding 

 losses by evaporation and radiation. 



