"RRIGATIOX FOR RICE 365 



the Mississippi River the water was formerly supplied from tne 

 river by putting a pipe through the levee, the land being highest 

 next the river and the drainage being away from the stream. 

 The water is now conveyed over the levee by means of a 

 siphon, the former method being prohibited by law because the 

 majority of disastrous breaks in the levees was attributed to 

 them. In southwestern Louisiana and southeastern Texas not 

 only are streams used for irrigation but advantage is taken of 

 a stratum of water that underlies this territory at a depth of 125 

 to 200 feet. When tapped, this water rises near the surface, 

 sometimes within twenty feet, and in a few instances flowing 

 wells have been obtained. Whatever the source of water, it is 

 pumped to raise it to the proper level. The individual planter 

 may have his own pumping outfit or water may be furnished an 

 extensive area from a single system, and the planter is charged 

 a certain percentage (usually one-fifth) of the rice raised for 

 water supplied, or a certain number of pounds of rough rice 

 (usually two barrels, or 324 pounds). 



Water for irrigation purposes should be uniform in temperature, 

 not too cold, free from noxious weed seeds and injurious salts. 



512. Amoant of Water Required. — The amount of water 

 required will var}^ with many conditions, including evaporation, 

 seepage, drainage and the rainfall. Where abundant and 

 obtained by gravity, larger quantities are likely to be used 

 than where it is pumped. The Louisiana Station says that in 

 that State each acre of rice is assumed to receive the equivalent 

 of one-half inch of water daily during ninety days ; this is 

 fort}'-five inches. Deducting twenty inches for rainfall leaves 

 twenty-five inches to be supplied by irrigation.^ 



The Office of Experiment Stations has measured the water 

 used at two plantations where water is obtained by pumping, 

 with the following results : - 



1 La. Bui. ']'], p. 382. 



« O. E S. Bui. 113, pp. 22-28. 



