828 EXPERIMENT STATION BECORD, [Vol. 38 



hispida, M. hispida sardoa, and M. tubcrculata. M. sciitcllata was the first to 

 reach maturity, but is described as ranking lowest in forage production. 



Two varieties of potatoes of the so-called " Hamakua Hybrid " designated 

 as Blue Ribbon and White Ribbon, respectively, were grown in comparative 

 tests for blight resistance with Portuguese Red and five common white var»e- 

 ties. Tlie hybrid varieties and the Portuguese Red exhibited a marked degree 

 of resistance and outyielded the white varieties in every instance. 



Report of the agronomy division, C. A. Sahr (Hawaii Sta. Rpt. 1917. pp. 

 48-55, pi. i).-^This reports the continuation of previous work (E. S. K., 37, 

 p. 131). 



In a study of soil aeration vnth rice, the increases favoring nonaeration in 

 1916 were 18.7 per cent for the spring crop, and 4.9 per cent for the fall crop, 

 and in 1917 3.1 per cent for the spring crop. 



Plantings of Burbank and Early Rose potatoes produced average yields of our 

 0.47 lb. per hill for both varieties, due to an attack of mites and to dry weather. 

 Three varieties of sweet potatoes were propagated for cuttings for distribution. 



Individual yields of alfalfa varieties, based on 9 cuttings per annum for a 

 period of 32 months,, were obtained as follows : Utah Common 30 tons of 

 green forage per acre, Kansas Common 28.4 tons, Peruvian 21.7 tons, and 

 Turkestan 14.7 tons. From the same number of cuttings for a period of 28 

 months, yields of Grimm, dry-land, and common alfalfa were obtained amount- 

 ing to 26.6, 26.4, and 9.3 tons per acre, respectively. 



Tests with tepary beans for seed have given varying results. A fall seeding 

 made a growth of 9 in., the plants dying before reaching maturity, while a sec- 

 ond seeding drilled in rows 1.5 ft. apart failed to fill the space between the 

 drills, but yielded at the rate of 10 bu. of shelled beans per acre. In a third 

 test made under drier conditions, with the beans drilled in rows 2 ft. apart 

 at the rate of 15 lbs. per acre, the crop attained maturity in 76 days and 

 yielded at the rate of 33.4 bu. per acre. 



A new variety ef pigeon pea introduced from India is said to have given 

 favorable results. 



Brief notes are given on limited field tests with various grasses including 

 Polytrias prcemorsa, blue couch (Digitaria didactyla) Napier (Pemiisetnm pnr- 

 ptircum). Wilder, fuzzy top, Australian blue, and Natal redtop. In sorghum 

 variety tests Sugar Drip was again first in yield of both grain and forage. 

 Nut grass control by spraying with a solution vof 1 lb. of white arsenic and 

 0.5 lb. of caustic soda in water to make 20 gal. when the plants were in full 

 bloom necessitated treatments at average intervals of 40 days the first year 

 and 65 days the second year. The third year, an interval of 9 months has 

 elapsed since the last spraying without the appearance of any blooms. 



Variety and fertilizer tests with corn failed completely due to severe attacks 

 by the leaf hopper {Percgrinus maidis), although the infestation was sufficiently 

 controlled by means of parasites (Ootctrastichns sp.) to obtain a crop of sweet 

 corn, the yield being at the rate of 43 bu. per acre. 



Small plantings of edible canna yielded at the rate of 23 tons edible tubers, 

 20.5 tons immature tubers, and 20.25 tons forage per acre. 



A white sweet variety of cassava from Trinidad and a red bitter sort common 

 to the islands, planted in the summer of 1915 and harvested in March, 1917, 

 yielded at the rate of 81 and 16.25 tons fresh roots per acre, respectively. 



A study of forage-crop problems was begun in July, 1916, on the military 

 reservation at Castner, Oahu, and experimental plantings were made of 

 numerous leguminous and nonleguminous forage crops. Chemical soil analyses 

 showed from 1.24 to 6.02 per cent of manganese dioxid in the surface soil 



