S2 



iEXPERIMENT STATION RECORD. 



Cooperative experinu'iits with a 5:!»:12 fiTtilizer were condncled on 3 sep- 

 arate plantations. The iiiixlnre was a]iplied at tlio rate of about SHO lbs. per acre, 

 at a total cost of approximately $10 per acre. On the I'unaluii iilantation, Oahu, 

 the increased yield was estimated at iiH per cent and the increased net profit at 

 .$G per acre. The experiment on a 1-year paddy field adjoining the rice trial 

 grounds at Waikiki showed an increased yield of paddy at the rate of 1,150 lbs. 

 per acre, or 39 per cent higher than on an unfertilized portion of the field. This 

 gave a net profit of $15 per acre due to fertilization. An adjoining test in 

 which the greater amount of nitrogen as sulphate of ammonia was applied 

 showed a still higher yield. The third cooperative experiment at I'alama plan- 

 tation near Honolulu showed an estimated increase of between 75 and 100 per 

 cent. 



In the experiment with upland rice grown with minimum irrigation all the 

 varieties from last year's test have been eliminated except Nos. 65, 68, and 

 154a, and possibly No. 19. The results with these varieties are indicated by 

 the following table: 



Results obtained loith a minimum amount of water upon upland rice. 



Variety. 



No. 19 (S. P. I. Inv. No. 1250S). 

 No. 65 (S. P. I. Inv. No. 17144) . 

 No. 68 (S. P. I. Inv. No. 17917) . 

 No. 68 (S. P. I. Inv. No. 17917). 

 No. 154 



Method of 

 planting. 



Drilled 



do 



do 



Aftermath. 

 Drilled 



Length of 

 growing 

 season. 



190 

 143 

 109 

 34 



145 



Total water 

 received 



(irrigation 

 and rain- 

 fall). 



Acre-inches. 

 47.0 

 30.6 

 23.5 

 6.9 

 30.0 



Yield of 

 paddy. 



Pounds. 



5,014 

 2,080 



Yield of 



hay 

 (approxi- 

 mate). 



Pounds. 

 10, 000 

 9, 926 

 6, 920 

 2,240 

 5,000 



Nos. 19 and 154 failed to set seed well, while the yield of paddy for No. 68 

 was not estimated. The rainfall in this table is included with the biweekly 

 Irrigation which was at the rate of 2i acre-inches per application, equivalent to 

 about 0.2 in. per day. Nos. 65 and 68 showed a 20 per cent increase in hay 

 yield and No. 19 a 50 per cent increase upon the application of double this 

 amount of water, but the grain yield did not increase in proportion. Growth 

 under submerged conditions failed to increase the yields of hay or paddy above 

 the point reached l)y the weekly application. All varieties failed to make a 

 crop with the application of 2i acre-inches once in 4 weeks, hence the biweekly 

 irrigation at the rate of 2* acre-inches is regarded as the minimum moisture 

 requirement for rice and the weekly application at that rate as about the 

 optimum. 



Under minimum moisture conditions 2 factors of equal importance in insur- 

 ing a crop are light seeding and deep and thorough tillage. Seeding at the 

 rate of 60 lbs. per acre (16 seedlings per foot) resulted in the failure of all 

 varieties to reach the fruit stage under 10 in. of rainfall, while the quick-ma- 

 turing variety. No. 68, thinned to stand 6 to 12 in. apart in drills 8 in. apart, 

 tillered well and produced perfect seeds. With 8 plants per foot, little tillei-- 

 ing and seed resulted. Root development under good tillage was from 4 to 6 

 times as great as in poorly prepared soil. " The same relative development was 

 (rue of plants set well apart and those that were crowded." 



Trials with salt-marsh rice gave acre yields of 14,212 lbs. total green weight, 

 5,852 lbs. air-cured matter as hay, and 2.842 lbs. as cured paddy. The product 

 was valued at $73.15 per acre as cured hay, and at $56.84 per acre as paddy. 

 The cost of harvesting, curing, and preparing for market would be about equal. 



