THE FIRST BOOK OF FARMING 



the biological work in the soil requires both chem- 

 ical and physical conditions. 



From the farmer's standpoint the physical prop- 

 erties seem to be most important, for the others are 

 dependent on the proper texture, moisture, heat and 

 ventilation which are controlled largely by tillage. 



Therefore the first effort of the farmer to improve 

 the fertility of his soil should be to improve his 

 methods of working the soil. 



Every one of these properties of the fertile soil, 

 and consequently every one of the conditions neces- 

 sary for the growth and development of plant roots, 

 is influenced in some way by every operation per- 

 formed on the soil, whether it be plowing, harrow- 

 ing, cultivating, applying manure, growing crops, 

 harvesting, or anything else, and the thoughtful far- 

 mer will frequently ask himself the question : " How 

 is this going to effect the fertility of my soil or the 

 conditions necessary for profitable crop produc- 

 tion?" 



MAINTENANCE OF FERTILITY 



The important factors in maintaining or increas- 

 ing the fertility of the soil are : 



The mechanical operations of tillage, especially 

 with reference to the control of soil water. 



The application of manures and fertilizers, es- 

 pecially with reference to maintaining a supply of 

 humus and plant food. 



Methods or systems of cropping the soil, with ref- 

 erence to economizing fertility. 



