136 SOIL MANAGEMENT 



to receive it. We call this preparation tillage. Its origin 

 takes us back from the modern plow and harrow, past rude 

 implements still in use by barbarous peoples, to the days of 

 the crooked stick of the savage. From the very earliest 

 times, men stirred the soil before planting the seed, not 

 knowing exactly why, but believing that they would 

 obtain larger crops by doing so. Civilized man has found 

 out several reasons why tillage is beneficial. We will now 

 note some of them. 



a. Tillage, we have already said, breaks compacted soil 

 apart and pulverizes it. Soil lying untouched for a year 

 or two becomes compact chiefly by the force of falling 

 rain, by the action of the water and ice within the soil, 

 and by the pressure of the upper soil layers. This shuts 

 out air from the soil. But we have learned that plant 

 roots need air. Tillage ventilates the soil, driving out foul 

 gases that it may contain, and making open spaces, or 

 pores, which take up fresh air. 



b. Tillage conserves moisture. In the last chapter it was 

 stated that soil moisture is perhaps the most important 

 point for farmers to watch in connection with their soils. 

 This was why so much space was devoted to the study of 

 drainage and irrigation. Capillary water escapes from the 

 soil either by direct evaporation or by being absorbed 

 by plant roots. It is the loss by evaporation that needs to 

 be regulated by tillage. 



In this matter the first thing to see to is to be sure that 

 the deeper layers of the soil store up all the water they 

 can hold. To help this process, where needful, the farmer 

 loosens up the under crust, sometimes by dynamite, but 

 more commonly by deep fall plowing. The idea in mind 

 is to get many open spaces for water storage deep in the 

 soil. 



Surface or shallow tillage is next resorted to in order to 



