12 BULLETIN 447, U. S. DEPAKTMENT OF AGRICULTURE. 



(3) After a field has once been covered with water, little further absorption 

 takes place, and no benefit can result from having water stand on or flow over 

 the soil for more than a few minutes. 



(4) The depth to which the water will penetrate depends upon the depth 

 to which the soil has been dried and cracked. 



The following poinjts brought out in this bulletin apply to the cul- 

 tural practices for these gumbo soils under either irrigation or dry- 

 land conditions: 



(1) No particular method of cultivation will be superior to others in influ- 

 encing the quantity of water absorbed, since this depends upon the degree to 

 which the surface soil is dried and cracked. The soil after harvest is usually 

 so dry that penetration takes place very readily, and any ordinary quantity of 

 rain that falls is absorbed, regardless of the cultural treatment. 



(2) Since the dry soil is naturally broken up to depths as great as would be 

 reached by either deep plowing or subsoiling, these operations can be of no great 

 benefit in water absorption. 



(3) Some method, such as dynamiting, by which the soil below the cracked 

 area could be broken up, might result in a temporary increase in the depth to 

 which water could easily penetrate. The natural swelling of the soil, however, 

 would cause it again to become compact every time it was wet. This would 

 make it necessary for the operation to be repeated each year, which would 

 involve an expense too great for this method ever to be considered seriously. 



ADDITIONAL COPIES 



OF THIS FUBLICATION MAY BE PROCURED FEOM 



THE SUPEKINTENDENT OF DOCUMENTS 



GOVERNMENT PRINTING OFFICE 



■WASHINGTON, D. C. 



AT 



5 CENTS PER COPY 



■WASHINGTON : GOVERN'MENT PRINTING OFFICE": ISIS" 



