628 THE SMALL GRAINS 



applied soon after seeding, remaining on from 1 to 6 

 days, depending on local conditions. The grain must be 

 well sprouted, but in some localities the soil and air are 

 at low temperatures at this season, and there is danger of 

 rotting the seed if the water remains on very long. In 

 California, the period of this irrigation should not be 

 more than 2 days. As the soil also should not dry out, 

 frequent irrigation is required until the plants come up 

 (Chambliss and Adams, 1915). In South Carolina, the 

 " sprout water," as this first application is called, remains 

 on 4 to 6 days. 



When the plants are 6 to 8 inches high, the long flooding 

 begins, and the water then turned on remains at a depth 

 of 3 to 6 inches, until the panicles are well filled and 

 drooping. In California, this submergence should begin 

 about 30 days after the plants come up, and the water 

 should remain at a depth of 5 to 6 inches. 



In South Carolina, there is a submergence of 10 to 12 

 inches, known as the " stretch water," when the plants 

 have 2 leaves, which depth is gradually reduced to about 

 4 inches. This period continues 20 to 30 days. There 

 is then a period of dry growth, when the crop is cleaned 

 of weeds, including volunteer rice, by hoeing. When 

 jointing begins, the final irrigation or "layby flow'' is 

 given. 



In the Texas-Louisiana rice district, and in Arkansas, the 

 irrigation season extends from 70 to 120 days, or an aver- 

 age of about 90 days. Early-sown rice, as it matures later 

 from the time of seeding, requires more days of irrigation. 



706. Some general principles of rice irrigation are as 

 follows : (1) The water should always stand at a uniform 

 depth over all the field ; (2) there should be a continuous 

 inflow and outflow, to avoid stagnation; (3) continuous 



