RICE EXPERIMENTS IN CALIFORNIA. 
19 
Table 14. — 'Annual and average yields obtained by different water treatment: 
Watarlbune rice at the Blags Eice Field Station, Biggs, Calif., from 1914 to 1921, 
inclusive. 
Yield per acre (pounds,. 
Year. 
chaneine i Sta ^^ nt Fluctuating 
Sf^ water ' 6 ~ de P th of 
Ssut i ^h sub- submerg- 
mergence. mergence. ence. 
1914 4. ,90 
1915 4,210 
1916 3,460 
1917 : 4,230 
1918 3, 615 
1919 : 3, 000 
1920 2,075 
1921 2 3,070 
Average 3, 556 
4.940 
5,290 
3,990 
4,160 
3,800 
3,690 
4,405 
4,360 
2,5.50 
3,625 
2,600 
2,950 
1.850 
2. 345 
2. 510 
2,990 
No sub- 
but soil 
kept moist. 
2,440 
2,480 
2,100 
2,860 
1,250 
670 
1,110 
3,331 
3,676 
1,925 
i Yields from single fifth-acre plats in 1914, 1915, 1916, 1918, and 1920 and from tenth-acre plats (dupli- 
cated where noted) in 1917, 1919, and 1921. 
2 Average of duplicated tenth-acre plats. 
The yields presented in Table 14 show that in five of the eight years 
the plat in which the water was slowly changing gave better yields 
than the plat that was stagnant. In the stagnant plat water was 
added about once a week. It is the writer's opinion that the addi- 
tion of several inches of cold water once a week has had a more 
detrimental effect on the stagnant plat than the stagnant condition 
itself. 
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■VO ' Si/3M£ffG£A/C£ 
A '/£/?*££■ y/£U7 P£/?AC/?£- /PoUA/DSf 
— — — — — — 355G 
■■■^■i^BHBMMMB 3,33/ 
■■■■■■^■■■■■■■^■B 3.67 G 
FigJ9. — Average acre yields of Wataribune rice obtained in experiments to determine the effect of dif- 
ferent methods of irrigation at the Biggs Rice Field Station during the 8-year period from 1914 to 1921, 
inclusive. 
FLUCTUATION OF DEPTH OF SUBMERGENCE. 
The plan of the experiment in fluctuating the depth of water was 
to submerge the land 30 days after emergence to a depth of 4 to 6 
inches and maintain this depth until the plants began to boot; then 
to lower the water to 1 to 2 inches and hold it at this depth until the 
first heads appeared, at which time the water was increased to the 
usual depth of 4 to 6 inches and held until the crop was mature or 
ready to drain. 
The plats on which the depth of water was changed from time to 
time yielded less than those submerged 2, 4, 6, and 8 inches deep 
during the entire submergence period (Table 13). However, it does 
not appear that the fluctuation of depth of water is nearly as harmful 
as is commonly believed. Annual and average yields are shown in 
Table 14. 
NO SUBMERGENCE. 
On one plat each year the land was kept moist at all times, but 
no water was held on it during the usual submergence period. The 
yields from this method of irrigation have ranged from 670 pounds 
