2 BULLETIN 1387, U. S. DEPARTMENT OF AGRICULTURE 
this method of irrigation the land soon became foul. On such foul 
lands water grass competes successfully with the rice crop, and the 
reduced yields which follow are often unprofitable. 
If the seed or seedlings of water grass are completely covered by 
water it is possible to smother this plant, whereas rice seed will ger- 
minate and emerge in a normal way even when fully submerged. 
This reaction of the two plants is the basis for control methods which 
are being developed and used on foul land. 
The method most commonly used is to sow the rice on a well- 
prepared seed bed and to submerge immediately to a depth of 4 to 
8 inches, maintaining this depth until the land is drained before har- 
vest. A second method is to prepare the seed bed reasonably well, 
although not quite so thoroughly as in the first method, and to sub- 
merge the land to a depth of 4 to S inches. The rice is then sown 
broadcast in the water, which keeps it from being covered by the 
natural slaking of the soil in the water. Submergence is maintained 
until the land is drained before harvest. A third method less com- 
Fig. 1 —Harvesting scene in a commercial rice field near Biggs, Calif. 
monly used is to drill or broadcast the seed, with immediate irrigation. 
The land is then drained and so remains until both rice and water- 
grass seedlings have emerged, when water is turned on to a depth of 
4 to 8 inches, where it is held until the land is drained for harvest. 
The first and second of these three methods are very effective in 
the control of water grass, the third being less satisfactory. 
The acreage, acre yield, production, and farm value on December 
1 of rice produced in California from 1912 to 1924, inclusive, are 
given in Table 1. These figures show a rapid increase in acreage 
from 1912 to 1920, inclusive, then a marked decline in acreage for 
1921, a slight increase for 1922, then a marked decrease in acreage 
for 1923 and 1924. It is interesting to note the difference in value 
of the 1919 crop, grown on 142,000 acres, and the 1920 crop, grown on 
162,000 acres. The reduction in value of nearly $10,000,000 shows 
how the rice growers were affected by the deflation in prices of farm 
crops. A harvesting scene in a commercial rice field near Biggs, 
Calif., is shown in Figure 1. 
