KICE CULTURE IN CALIFORNIA 37 
Strong winds sometimes blow fiom the north or the south, but as 
a rule there is little wind. 
The average evaporation for June, July, and August from 1913 to 
1924, inclusive, was 24.834 inches. The average evaporation from 
April to October, inclusive, for 1914, 1915, 1921, 1922, and 1923 
was 42.090 inches. 
On foul land rice sown broadcast and immediately and continu- 
ously submerged or sown broadcast in the water and kept sub- 
merged thereafter appears to have three distinct advantages over 
rice irrigated in the old way: (1) Continuous submergence controls 
to a marked extent the common forms of water grass and also spran- 
gletop, and the rice plants so irrigated are more vigorous and thrifty 
than those grown by the old method of irrigation; (2) depending 
upon the date of seeding, the rice matures from 5 to 10 days earlier 
than when irrigated in the old way, the difference being less from 
early than from late dates of seeding; (3) as a result of water-^rass 
control and better developed rice plants, the acre yields are materially 
increased by continuous submergence, and because of earlier maturity 
the danger of crop loss by early fall rains is lessened. 
The results in the date-of-seeding and depth-of-seeding experi- 
ments indicate that the rice should be sown broadcast comparatively 
early and immediately submerged about 6 inches. 
Experimental results indicate that seeding in the water has no ad- 
vantages over seeding on the soil, except that usually less seed is 
required to obtain good stands. The increased cost of sowing in the 
water, however, more than offsets any saving in seed. 
When rice is drilled and immediately submerged it appears that 
considerable seed rots, this often resulting in poor stands and low 
yields. When stands of rice are poor such weeds as the annual sedge, 
redstem, and cat-tail increase rapidly. 
When rice is drilled or sown broadcast and irrigated and drained 
at frequent intervals until emergence and then is continuously sub- 
merged, shallow submergence at 2 and 4 inches does not effectively 
control water grass. Deep submergence 6 and 8 inches aids in the 
control of water grass, but such depths of submergence also suffocate 
.so much rice that low yields are produced. This method of irriga- 
tion is distinctly inferior to continuous submergence, both in the con- 
trol of water grass and in yields of rice. 
The results show that it does not pay to grow rice on a seed bed 
prepared merely by double disking rice stubble land, because such 
weeds as spike rush, cat-tail, slender aster, canary grass, and per- 
ennial sedge reduce yields below profitable limits. Good plowing 
aids materially in the control of these weeds. During the thiee years 
1922, 1923, and 1924 the average acre yield of the spring-plowed 
land was 754 pounds more than for the disked stubble land. 
The results of the rate-of-seeding and meihod-of-irrigation experi- 
ments show that the best method of irrigation on foul land consists 
of continuous submergence after broadcasting the rice on the soil. 
The results also indicate that probably rice should be sown at a 
heavier rate when grown by continuous submergence than when 
grown by deferred submergence by the old method of irrigation. 
The results of rate-of-seeding experiments with three varieties in- 
dicate that on old land rice probably should be sown at the rate of 
150 pounds per acre when grown b} T the old method of irrigation. 
