EDIBLE CANNA IN WAIMEA DISTRICT OF HAWAII 35 
vesting on a large scale is as yet an unstandardized procedure, and 
partly to the employment of untrained help in the work of harvest- 
ing, making it impossible to insure that the tops are severed with the 
same average length of stem attached to the rootstocks. In addi- 
tion, the quantity of roots, dead scales, and soil adhering to the canna 
rootstocks varies under different weather conditions. 
Lack of precision in cutting off the top at the exact apex of the 
rootstock makes it difficult also to estimate the tare. In the sub- 
surface types the exact juncture of rootstock and stalk can be deter- 
mined only by a careful inspection of a longitudinally cut section of 
the rootstock. (Fig. 18.) During later harvests great care was taken 
to cleanse the rootstocks of all adhering soil and to cut the tops as 
closely as possible to the rootstocks so that the tare values would be 
more nearly constant. The values can not be assumed to be constant, 
however, since they are so easily affected by the factors mentioned 
above. 
The tare will likely have to be estimated in actual operation, 
especially if the rootstocks are purchased by the ton from growers. 
Two methods of procedure are feasible for the purpose. One is 
that used in the present study. If accurate results are expected 
considerable care must be exercised in the selection of representative 
samples and determination must be made on lots of good size. In 
the second method, the price per ton is based on the percentage of 
starch extracted. A basic price could be paid plus a bonus for each 
percentage of extraction over the minimum. The actual percentage 
of starch in the rootstock could be determined by attaching a con- 
tinuous sampler to the shredder. The second method seems prefer- 
able to the first since it takes into account the tare and also differ- 
ences in actual percentage of starch in the rootstock. However, 
this method can not well be used until milling operations are com- 
pletely standardized. The first method can be used during the initial 
stages of the industry. 
FEED AND FERTILIZER VALUE OF CANNA TOPS AND PULP 
In order to determine the fertilizer elements in the different parts 
of the canna plant and the value of these parts as feed and as green 
manure, 5 hills of canna were dug from an 18-month-old field at 
Waimea. The tops were classified and the separate groups weighed. 
Approximately 50 pounds of rootstocks were shredded and the starch 
extracted by repeatedly washing the pulp in a cloth bag. Samples 
of the pulp, the rootstocks, and the three groups of tops were then 
dried and analyzed for their nutritive and fertilizer constituents. 
Group 1 contained an even distribution of shriveled tops and tops 
the stems of which were still succulent. Group 2 also contained an 
even distribution of the older and younger members. Group 3a 
was largely medium to old and contained practically none of the 
youngest stalks of the group. Table 14 compares the composition 
of different parts of the canna plant and other carbohydrate feeds. 
