10 BULLETIN 1155, U. S. DEPARTMENT OF AGRICULTURE. 
In five of the years the 2-inch depth of seeding produced the highest 
yields; in two, the plats sown at the 1-inch depth, and in one, those 
sown at the 3-inch depth yielded best. The highest average yield, 4.423 
pounds per acre, was obtained from the plats seeded 2 inches deep. 
The plats seeded 1 inch deep ranked second, with an average yield of 
4,279 pounds per acre. The average yields in the depth-of-seeding 
experiments with rice at the Biggs Field Station from 1913 to 1921, 
inclusive (1920 omitted), are shown graphically in Figure 4. 
y/£LD P£/? s4C/P£ fPOlSA/Ds) 
Fig. 4.— Average acre vields of Wataribune rice obtained in the depth-of-seeding experiments at the 
Biggs Rice Field Station during the 9-year period from 1913 to 1921 (1920 omitted). 
On an exceptionally good or a rough cloddy seed bed the best stands 
are usually obtained from shallow seeding. On heavy soil, such as the 
Stockton clay adobe, if the seed bed is finely pulverized and the rice 
is sown too deep, the flooding to start germination will run the soil 
together. This makes it very compact, keeps it cold, and results in the 
rotting of considerable seed. Again, if such a soil is cloddy and 
rough and the seed is sown deep, the flooding to start germination 
will slack the clods and bury the rice so deep that the plants are 
unable to emerge. Therefore, our experiments, observations, and 
experience all strongly indicate that on heavy soil shallow seeding, 
1 toH inches, is preferable to deeper seeding. On soils of lighter tex- 
ture deeper seeding may be advisable. Some rice growers broadcast 
the rice on plowed or disked land and depend upon the first flooding 
of the field to bury the seeds. Although good yields have been 
obtained in this way. this method of seeding should not be practiced 
when the crop is not to be submerged continuously after seeding. 
RATE OF SEEDING. 
Rate-of -seeding experiments were begun in 1913, when plats were 
sown to Wataribune rice at rates of 60, 80, and 100 pounds to the 
acre. After the land had been in rice for several years it became 
necessary to increase these rates in order to have the stands thick 
enough on all plats to aid in keeping down weeds. Beginning in 
1918, rates of 110, 130, and 150 pounds were used. In 1921 new 
rate-of-seeding experiments were begun, with three varieties and 
six rates of seeding for each variety. 
EXPERIMENTS FROM 1913 TO 1921. 
The yields from duplicate tenth-acre plats in the rate-of-seeding 
experiments during the 9-year period from 1913 to 1921 are shown 
in Table 8. The preparation of the land and the time, depth, and 
manner of seeding were the same on all plats. As stated above, 
the rates used from 1913 to 1917, inclusive, were 60, 80, and 100 
pounds'per acre; from 1918 to 1921, they were 110, 130, and 150 
pounds. A set of plats was drilled and one sown broadcast at these 
rates each vear. 
