RICE EXPERIMENTS IX CALIFORNIA. 
applied at three stages of growth, the first stage being when the plant- 
were about 3 inches high. As previously stated, the plats to which 
fertilizer was applied at this stage in general yi elded more than those 
which were fertilized later. The other and probably the more impor- 
tant factor in reducing crop yields during the second period was the 
increase in weed growth. The land had been continuously in rice 
since the beginning of the experiment, and weed growth increased 
with each successive crop. 
Table 22. — Average yields of Wataribune rice obtained in the fertilizer experiments at the 
Biggs Rice Field Station, Biggs, Calif., in the 3-year periods from 1914 to 1916 
1917 to 1919, inclusive. 
Yield per acre (pounds). 
Fertilizer. 
1917 to 1919.* 
1914 to 
1916.1 
A stage. 3 B stage.* C stage.* 
Manure 
Sulphate of ammonia . 
Dried blood 
Cottonseed meal 
Sulphate of ammonia . 
Acid phosphate 
Sulphate of ammonia. 
Sulphate of potash. . . 
4,488 
4,260 
4, 255 . 
4. 192 
3,973 
3,920 
3,943 
3,493 
3,340 
3,297 
3,053 
3,070 
2,733 
3,477 
3,093 
Sulphate of ammonia. 
Sulphate of potash . . . 
Acid phosphate 
Sulphate of potash . 
Nitrate of soda 
Acid phosphate 
Sulphate of potash . 
Acid phosphate — 
No fertilizer. 
Lime 
) 
3,240 
3, B32 
3, 795 
3,630 
2,950 
2,850 
2,873 
1 
3,560 
2,830 
« 3,609 
3,322 
7 2,732 
2,333 
3,140 
3,043 
3,043 
2,6S0 
3,277 . 
2,873 
2,547 
2, 617 
2,437 
2,587 
2,760 
2,283 
1 Yields of duplicated tenth-acre plats each year. 
* Yields of single tenth-acre plats each year. 
* Fertilizer applied when the rice plants were 3 inches high. 
4 Fertilizer applied when the first heads were emerging. 
8 Fertilizer applied two weeks after first heading. 
8 Average yields from 12 tenth-acre plats each year. 
J Average yields from 7 tenth-acre plats each year. 
VARIETAL EXPERIMENTS. 
Thousands of varieties and strains of rice are grown in the various 
rice-producing countries of the world. One of the principal lin< 
experimentation at the Biggs Rice Field Station has been the testing 
of many varieties of rice from various sources in the hope of finding 
some that are superior in yield and milling quality to those thai 
now being grown commercially in California. 
CLASSES OF RICE. 
The varieties of rice most commonly grown in the United States are 
classed roughly as long-grain, medium-grain, and short-grain. The 
short-grain rices have small stalks, narrow leave-, and short kernels. 
The medium-grain rices have rather large stalks, comparatively wide 
leaves, and kernels of medium length. The long-grain rices have 
