RICE EXPERIMENTS IN CALIFORNIA. 18 
the rate of 175 pounds per acre was less than the average yield from 
the 150-pound rate, but higher than that from any of the other rates. 
The 1921 yields indicate that 150 pounds per acre is probably the 
best rate of seeding on old land. These yields were obtained on an 
ideal seed bed, much better than the usual seed beds on commercial 
fields. Therefore, on commercial seed beds the higher rates of seed- 
ing could be expected to give even greater differences in yield. Thin 
stands result in excessive tillering, uneven ripening, and usually a 
poor quality of rice. 
FACTORS INFLUENCING THE RATE OF SEEDING. 
Many factors must be taken into consideration in determining the 
best rate of seeding. Among these are previous cropping, character 
of seed bed, kind of land, time of seeding, seed, variety, manner of 
seeding, drainage, and method of irrigation. 
More seed is required to obtain a good stand on land on which 
several crops of rice have been grown than on new land. Rice on 
old land does not stool as well as on new land. Therefore, it is 
necessary to increase the rate of seeding as the land becomes old. 
More seed is required to obtain good stands on a rough seed bed 
than on a good one. More seed also is required on heavy, cold land 
than on lighter, warmer soil. 
If rice is seeded early in the spring, when the soil, water, and air 
are all cold, more seed is required than for seeding later, when con- 
ditions are more favorable for germination. 
A smaller quantity of well-matured, recleaned seed than of inferior 
seed is required to secure good stands. 
All varieties should not be seeded at the same rate, because some 
stool much more freely than others. Wataribune rice stools much 
more than Colusa (C. I. No. 1600) under the same conditions. 
Wataribune does not stool as much on old land as it does on new or 
second-year land. All varieties stool more heavily on rich land 
than on poor land. 
Less seed is required where rice is drilled than when sown broadcast. 
On poorly drained, cold land more seed is required to secure good 
stands than on other soils, because conditions are usually unfavorable 
for germination on poorly drained soils. 
If the best methods of irrigation are not practiced or if water for 
the initial flooding is not plentiful and therefore a long time is taken 
to cover the field, more seed per acre is required, because some of the 
seed is likely to rot before the field is covered and the water removed. 
Because of all these factors it is not possible to say what rate of 
seeding is best under all conditions. Many factors should be con- 
sidered, and usually all favorable factors are not present in any one 
place at the same time. 
Early varieties on new land should be sown at about 100 to 110 
pounds per acre, and late varieties at 90 to 100 pounds. Early 
varieties on second-year land should be sown at 110 to 120 poundV 
per acre, and late ones at 100 to 110 pounds per acre. On third and 
fourth year land the rates should be increased in each ease from 5 to 
15 pounds per acre. 
