BICE EXPERIMENTS IN CALIFORNIA. 
27 
Table 20. — Annual and average yields of Wataribune rice obtained in the fertilizer ex- 
periments at the Biggs Rice Field Station, Biggs, Calif, in the 3-year period from 1917 
to 1919. inclusive, vjith the average increase or decrease in yields and net values due 
to fertilizers, 1 
Fertilizer. 
Yield per acre (pound? . 
Gain or loss per acre. 
1917 1918 1919 Average. Pounds 
value. 2 
Manure 3, 960 
Sulphate of ammonia 4, 360 
Sulphate of ammonia \ , 9 ^ 
Acid phosphate / % Z4U 
Dried blood 4, 200 
Sulphate of ammonia ) 
Sulphate of potash - 4, 020 
Acid phosphate j 
Acid phosphate 3, 520 
Sulphate of ammonia 1 ,con 
Sulphate of potash / 6 > ^ 
Sulphate of potash 3, 730 
Nitrate of soda 3, 520 
No fertilizer « 3, 690 
Sulphate of potash \ Q - 5n 
Acid phosphate / 6 > ^ u 
Lime 3, 390 
4,720 
3,910 
3,640 
3,720 
3, 770 
3,500 
3,490 
3,190 
3,280 
2,706 
3. 280 
3, 1-50 
2,210 
1 Yields from tenth-acre plats, fertilizer applied when the rice plants were approximately 3 inches high. 
5 The average price of rice for 1917. 1918, and 1919 was $4.90 per 100 pounds. This column shows the 
value of the additional crop less the actual cost of fertilizers. The cost of freight on fertilizers, the cost of 
application, and the extra cost of handling the additional crop are not taken into account. 
3 Average yields from 7 tenth-acre plats. 
SUMMARY OF FERTILIZER EXPERIMENTS. 
Table 21 shows the average yields obtained each year in the ferti- 
lizer experiments, the average yields for the 6-year period from 1914 
to 1919. the increase or decrease in yield as compared with the check, 
and the value of this increase or decrease. 
The average increase in yield from the fertilizers ranges from 25 
pounds for acid phosphate and sulphate of potash combined to 1.046 
pounds per acre for manure. The application of lime caused an 
average decrease in yield of 342 pounds. Manure produced the 
largest increase in yield and net value per acre. Sulphate of am- 
monia ranked second, dried blood ranked third, and acid phosphate 
and sulphate of ammonia combined ranked fourth in both inc. 
and net return. Acid phosphate alone, acid phosphate and sulphate 
of potash combined, and the combination of sulphate o( ammonia, 
sulphate of potash, and acid phosphate, while causing inc 
yield, cost more than the additional crop was worth. 
It should be remembered that the increases in yield due to the 
various fertilizers have been multiplied by the average price of rough 
rice (S3. 40 per 100 pounds) for the period under discussion L914 to 
1919). This average price no doubt is much higher than it would 
have been or will be during normal times, and therefore the net 
returns per acre from the use of the various fertilizer- as shown 
in Table 21 are much higher than one should expect when conditions 
return to normal. 
