76 



TILLAGE FOR CORN 



strated on such soils (when undisturbed) that 30 to 60 per cent of 

 the water lost may be saved by cultivation. 1 



Water Loss in Fields. In a corn field conditions are quite 

 different from those on a fallow soil. (1) Conditions favoring 

 evaporation from the soil surface are largely removed. (2) The 

 upward movement of soil moisture is intercepted by roots. 



1. Set a pan of water on bare ground and another on the ground 

 in a wheat field. The water surface in the open will lose moisture at 

 the rate of one-half inch per day in dry weather, while the water 

 surface in the wheat field will probably not lose as much in a week. 

 A similar pan of water in a corn field will lose more than in a wheat 

 field, being more exposed, but much less than on a bare (fallow) 

 field. 2 



2. In a wheat or corn field a mass of roots fills the upper eight 

 to twelve inches of soil, intercepting any upward movement of 

 water. This would be especially true in a dry time, and it is doubt- 

 ful if any appreciable amount of water could pass through this mass 

 of roots to the surface. 



Conserving Moisture in a Corn Field. From the above we 

 may conclude that in a fallow field moisture can be conserved by 

 cultivation. That in a corn field, up to the time the plants are 

 twelve inches high, the conditions are similar to a fallow field, but 

 from this time on conditions rapidly change as the tops protect the 

 surface and the roots occupy the soil. 



Cultivation should be effective in conserving moisture during 

 early growth, but not very effective after corn is five or six feet in 

 height. This conclusion has been verified by numerous experiments, 

 which the following will illustrate : 



Effects of Different Treatments After Corn Is High 



1 Widstoe, John A. : Dry Farming, p. 155. 



a Nebraska Agricultural Experiment Station, Annual Report, 1911, 

 p. 97. 



