J. S. AGRICULTURAL EXTENSION SERVICE 



Figure 13. Natural grass cover; an efficient retard- 

 ing agent. 





U. S. AGRICULTURAL EXTENSION SERVICE 



Figure 14. An ordinary farm pasture helps water 

 penetrate the soil. 



Figure 15. Heavy planted alfalfa promotes infiltra- 

 tion and underground storage, on which it draws 

 heavily. 





U. S. AGRICULTURAL EXTENSION SERVICE 



