64 A YEAR IN AGRICULTURE 



on land plowed in the fall and similar land plowed early in 

 the spring are very slight. Sticky clay land should not be 

 plowed when it is so wet as to slip off the mouldboard in a 

 shiny condition. Land that is likely to wash because of 

 steepness or other conditions should be plowed late in the 

 winter rather than early, especially if it is protected by a 

 cover-crop. 



Purpose of plowing. One purpose of plowing is to enable 

 the land to store water and retain it. Fall plowing pro- 

 vides for the storage of water in the soil ; spring plowing 

 provides for its retention. But to this qualification there 

 needs to be added the statement that spring plowing is 

 likely to hasten the evaporation of soil moisture unless the 

 plow is almost immediately followed by the harrow. "Water 

 escapes very rapidly from the surface of a newly plowed 

 field. Following the plow with the harrow while the surface 

 soil is still fresh reduces the exposed surface and so retards 

 evaporation. It also retards the rise of the water from the 

 subsoil, thus retaining it where the plant roots will need it 

 during the growing season. Plowing also increases the feed- 

 ing area of the corn roots and helps to make plant-food 

 available. 



Depth of plowing. The depth of plowing for corn will be 

 determined largely by the depth of previous plowings. It 

 is not wise to turn a large amount of raw subsoil up to the 

 surface. Usually it is well to bring a small amount of new 

 soil under the direct influence of sun and rain, thus prepar- 

 ing it to be useful to subsequent crops. It is to be remem- 

 bered that it is the mellowed soil that contributes most to 



