28 
BULLETIN 1155, U. S. DEPARTMENT OF AGRICULTURE. 
Table 21. — Annual and average yields of Watarlbune rice obtained in the fertilizer experi- 
rmnts at the Biggs Rize Fizld Station, Bigjs, Calif., in the 6-year period from 1914 to 
1919, inclusive, with the average increase or decrease in yields and net values due to 
fertilizers. 
Yield per acre (pounds). 
Fertilizer. 
1915 i 
1916 1 
5,000 
4,580 
4,485 
4,235 
3.825 
3.905 
4,240 
3,870 
4.225 
4,025 
3.165 
3.200 
4.420 
3,490 
< 3.914 
4,055 
< 3,221 
3,040 
4.315 
3,580 
4,275 
3,415 
3,750 
3,085 
1917 2 1918 ? , 1919- Average. 
Gain or loss per 
acre. 
Pounds 
Net 
value. 3 
Manure 4 
Sulphate of ammonia ' 4 , 
Dried blood I 4, 
-Sulphate of ammonia \ - 
Acid phosphate / ' 
Xitrateof soda 3, 
Sulphate of potash I 4, 
Sulphate of ammonia \ „ 
Sulphate of potash 
4.720 
3.910 
3.720 
4,240 3,640 
3,280 
3,190 
3.150 
2.210 
2,100 
4,216 
3,877 
3,798 
2.550 3,725 
1.750 
1,930 
3.323 
3,386 
Nofertilizer *3, 
Acid phosphate 3, 
Sulphate of ammonia. 
Sulphate of potash 
Acid phosphate 
3,890 3.490 
Sulphate of potash \ 9 QQn 
Acid phosphate / ~' yyu 
Lime. 
3,130 
5 2,706 
3,500 
3,770 
3,280 
1,760 
1,900 3,507 
+1,046 
+707 
+628 
+555 
+ 153 
+216 
+337 
+$30.64 
+ 19.49 
+ 15.30 
+11.37 
+1.58 
+ .81 
+ .38 
5 1,799 
1,600 
1,930 
1,680 
1,850 
3,170 
3,252 
3,562 
3,195 
2,828 
+82 
+392 
+25 
-342 
-.16 
— 70 
-8.63 
-25.13 
1 Average yields from duplicated tenth-acre plats. 
2 Yields from the tenth-acre plats to which fertilizers were applied when the rice was 3 inches high. 
« The average price of rice from 1914 to 1919, S3. 40 per 100 pounds. This column shows simply the value 
of the increased production less the cost of fertilizers (Table 17), without taking into account the freight on 
fertilizers, the cost of application, or the cost of handling the increased crop. 
1 Average yields from 12 tenth-acre plats. 
* Average yields from 7 tenth-acre plats. 
The data show that, even under normal conditions, however, 
manure, sulphate of ammonia, and dried blood increase the yields 
of rice to a marked extent, and in time sulphate of ammonia or dried 
blood will probably be used on commercial fields in California if the 
relative prices of rice and fertilizers justify such use. 
Manure is cheap but is difficult to apply. It is scarce and also 
carries weed seeds. These are the main objections to manure as a 
fertilizer. Dried blood and sulphate of ammonia can be applied with 
a fertilizer attachment on the drill at seeding time, and this is a 
strong point in their favor. There is little difference in the results 
obtained from dried blood and sulphate of ammonia, but sulphate of 
ammonia is easier to apply and for this reason should be the more 
popular on commercial fields. 
Table 22 shows the average acre yields obtained from the plats to 
which various fertilizers were applied in the 3-year period from 1914 
to 1916 and also the average yields from the plats to which fertilizers 
were applied at different stages of growth of the crop in the period 
from 1917 to 1919. Jn every case the average yields in the 3-year 
period from 1917 to 1919 were lower than the yields from the corre- 
sponding plats in the earlier period, 1914 to 1916. These lower yields 
were undoubtedly due to two causes, and it is impossible to say which 
one of these was the more important. In the earlier period the fer- 
tilizer was applied before seeding time and was available to the crop 
during the entire period of its growth. In the later period it was 
