14 
BULLETIN 1387, U. S. DEPARTMENT OF AGRICULTURE 
Table 8.— Yields of Caloro rice obtained on plats sown on two dates, both broadcast 
and drilled, and submerged at various depths after the rice emerged at the Biggs 
Rice Field Station in 1922, 1928, and 1924. 
.Submergence 
Acre yields (pounds) 
Date and method of seeding 
1922 
1923 
1924 
Aver- 
age! 
Compared 
with check 
Date 
Depth 
(inches) 
Gain 
Loss 
April 25: 
May29». 
..do.2... 
... do.«.„ 
..(10.2... 
...do.a... 
..(10.2... 
..do.2... 
..do.»... 
Junel5«. 
..do.-f... 
June 8 5 _ 
..do. 5 -.. 
.do. 6 -.. 
do. 6 . 
2 
2 
4 
4 
6 
6 
8 
8 
6 
6 
4 
4 
6 
6 
8 
8 
6 
6 
2,280 
2,690 
2,580 
2,450 
2, 060 
2,480 
2,300 
2, 270 
2,590 
2,450 
2,050 
2, 0»i0 
1,995 
2,085 
1,825 
1,735 
1,830 
2,110 
2,240 
1,985 
2,095 
1,815 
1,520 
2,145 
1,645 
2,004 
1,220 
1,675 
1,210 
1,320 
905 
825 
1,210 
1,605 
1,390 
1,690 
1,135 
1,4(35 
1,510 
1,660 
1.530 
1,870 
870 
1,227 
1,833 
2,163 
1,985 
1,967 
1,888 
1,985 
1,783 
2,095 
1,702 
1,894 
1,635 
1,867 
1.C02 
1 709 
131 
269 
283 
73 
186 
91 
81 
201 
Drilled.-. 
Broadcast on soil . 
Drilled 
Broadcast en soil. „ ... 
Drilled 
Broadcast on soil 
Drilled 
Broadcast on soil 3 
[""""" 
Drilled3._. 
May 5: 
Broadcast on soil... 
Drilled 
Broadcast on soil 
Drilled 
425 
177 
392 
12 
155 
Broadcast on soil 
Drilled 
Broadcast on soil 3 
..do.\_. 
June 25. 
do 
1,365 
1,280 
1,210 
i r,on 
410 
Drilled'.. 


i The two-year average for (he May 5 date of seeding. 
'Submerged on Maj 24, 1923, and on May 22. 1924. 
' Used as checks on the two methods of seeding, respectively, for April 25 and May 5. 
4 Submerged on June"!.', L924 
5 Submerged on June 4, 1923. 
The young rice plant or seedling apparently is unable to adjust 
itself to the sudden change from a dry or moist soil to a submerged 
life. Many young plants are suffocated when submerged in deep 
water (6 and 8 inches), and those which emerge to the water surface 
are slow in regaining, if they ever fully regain, their normal viability. 
However, when the rice seed germinates under water and the seed- 
lings emerge through the water such plants appear to be more vigorous 
than plants grown by the old method of irrigation. 
SPRING PLOWING AND DISKING OF STUBBLE LAND COMPARED 
Experiments comparing spring plowing and disking were conducted 
on land which had been alternately cropped to rice and fallowed in 
the cultural experiments from 1914 to 1921. The land produced a 
rice crop in 1921. The 1922 crop was the sixth rice crop on this 
land in 9 years, the 1923 crop was the seventh rice crop in 10 years, 
and the 1924 crop was the eighth rice crop in 11 years. 
In the spring one series of plats was double disked and harrowed 
each year during the three years 1922, 1923, and 1924. A second 
series of plats at the same time was spring plowed, double disked, 
and dragged. These tillage operations prepared a good seed bed on 
the spring-plowed land, but a poor, hard, grassy seed bed on the 
disked stubble land. 
In these experiments alternate plats, usually inclosed within the 
same levees, were sown broadcast and drilled. Each year the rice was 
