10 
BULLETIN 1387, U. S. DEPARTMENT OF AGRICULTURE 
Table 6. — Yields of Caloro rice on plats submerged immediately after broadcast 
seeding in date-of -seeding and depth-of -submergence experiments at the Biggs Rice 
Field Station in 1922, 1928, and 1924 
Seeding 
Submergence | 
Acre yields (pounds; 
Compared with 
check 
Date 
Method 
Date 
Depth 
(inches) 
1922 
1923 
1924 
Aver- 
age 
Gain 
Loss 
April 25. 
Broadcast on soil 
Apr. 25i . 
. 
3,295 
2,365 
2,395 
2, 685 
874 
Do.... 
do 
__.do.i_.. 
6 
2 3, 520 
2 3,265 
2 3, 125 
3,303 
1, 492 
Do.... 
do 
...do.'... 
8 
3,265 
2,115 
2, 020* 
2,080 
2,467 
656 
May 5.. 
do 
May 5... 
4 
2,605 
2,530 
2,405 
594 ! 
Do.... 
do 
...do.... 
6 
3,290 
2,655 
2, 245 
2,730 
91," .._ 
Do..- 
dd 
...do.... 
8 
3,075 
2, 620 
2,430 
2,708 
897 ' 
May 15 . 
do 
Mayl .. 
2 
2.850 
2,090 
1,270 
2,070 
259 , 
Do.... 
do - 
...do.... 
4 
3,695 
2,075 
1,655 
2,475 
664 ! 
Do.... 
do... 
...do.... 
6 
4,250 
2.380 
1,675 
2,768 
957 ._ 
Do.... 
do 
...do.... 
8 
3, 645 
1,925 
1, 195 
2.255 
444 
May 1(3 . 
Broadcast in the water. 
...do.... 
4 
3,700 
2, ISO 
1,735 
2,542 
731 
Do.... 
do 
...do.... 
6 
2,805 
1,625 
1,010 
1,813 
2 
Do.... 
do 
...do.... 
8 
4,010 
2, 130 
1,310 
2,483 
672 
May 25 . 
Broadcast on soil 
May25». 
4 
3,515 
« 1, 560 
<810 
1,962 
151 
Do... 
. do 
...doJ... 
6 
2,785 
< 1,400 
* 745 
1, (.43 
168 
Do... 
do 
...do.<... 
8 
3,110 
« 1, 460 
* 760 
1,777 
34 
April 25. 
Drilled 
Apr. 251. 
6 
1,740 
2,392 
1,777 
1,970 
159 
Do.... 
Drilled (check) . 
June 15 5 _ 
6 ! 
3, 25 
1,572 
610 
1,811 
•Submerged on Apr. 28, 1922. 
2 Yields increased by an old fill a u u previous treatment. 
'Submerged on May 26, 1924. 
* Affected by seepage. 
'Submerged on June 11, 1924. 
The three-year average acre yield of the plats sown broadcast and 
immediately submerged 4, 6, and 8 inches on May 15 is higher than 
that of the plats sown broadcast in 4, 6, and 8 inches of water on 
May 16. The difference, 220 pounds per acre, may be significant. 
The highest three-year average acre yield of the plats sown broad- 
cast and immediately submerged on May 15 was obtained from the 
plats submerged 6 inches; the highest acre yield for the plats sown 
broadcast in the water was obtained from the plats submerged 4 
inches. The cost of sowing in the water is much higher than for 
sowing broadcast on the soil, and although it is possible to obtain 
a stand with less seed when the rice is sown in the water this saving 
in seed would likely be more than offset by the increased cost of 
seeding. 
The yields of plats sown broadcast and plats drilled and submerged 
6 inches on April 25 are much higher each year for the plats sown 
broadcast. When rice seed is drilled and immediately submerged 
considerable seed rots, and this results in poor stands and usually in 
low yields. 
Rice sown broadcast and immediately submerged 4, 6, or 8 inches, 
or rice sown in the water for all dates of seeding except for the plats 
submerged 6 and 8 inches on May 25, gave higher average yields 
than the check plats. The average increase in yields over the check 
plats varied from 2 to 1,492 pounds per acre. Slight differences in 
yield are certainly not significant; larger differences, 400 pounds per 
acre or more, probably are. Many of the modifications show in- 
creases of more than 500 pounds per acre above the control, and the 
methods of irrigation which result in these increased yields are appar- 
ently superior to the method used on the control plats. 
