Lynne Wong's PhD thesis

Snow (1974) tested eight cane varieties of 11-month maturity, where the fibre/pith ratio
varied from 0.66 to 1.52 and fibre % cane (presumably total fibre % cane) ranged from 9.0
to 12.2.
Moodley (1991) tested four different varieties of cane aged 19 months and found that
although the fibre/pith ratio did vary from 2.00 to 2.86, there was not much difference in
pith % cane, but the hard fibre % cane did vary over a wide range from 8.85 to 12.86.
In this study, with the four cane varieties aged 52 weeks, fibre/pith ratio in cane ranged
from 1.06 to 1.21, in agreement with values found by Snow (1974). Hard fibre % cane
varied from 3.68 to 4.46, pith % cane from 3.18 to 4.03, and fibre % cane from 6.98 to
8.27. As mentioned earlier, the fibre % cane values appear to be low, and so do those of
hard fibre % cane.
3.5.3.3 Effect of extraneous matter on fibre/pith ratio in cane
Moodley (1991) found that, by adding 12% by mass of cane tops to clean cane, hard fibre
% cane is greatly increased from 8.78 to 10.99, and the pith % cane changes from 4.03 to
3.16 giving a fibre/pith ratio of 3.45, whereas with the addition of 12% by mass of dry
leaves, hard fibre % cane was greatly increased to 14.06 and the pith % cane to 4.11 giving
a fibre/pith ratio of 3.45 also. He also found that drought conditions affect fibre/pith ratio,
normally it is 60:40, whereas during drought it changes to 40:60.
In this study, by using data from Tables 3.8 – 3.10, the mass of stalk plus rind can be
considered as clean cane, the effect of the presence of dry leaf in gross cane (clean cane +
dry leaf) on hard fibre % cane, pith % cane, total fibre % cane and fibre/pith ratio in cane
was evaluated and shown in Tables 3.14 – 3.16 for the four cane varieties at three ages.
The first fraction > 1.18 mm collected after dry sieving was considered to be the hard fibre
and the second fraction < 1.18 mm, the fines or pith. Similarly, the effect of green leaf and
tops on the above parameters was also assessed. It can be seen that all the extraneous
matter studied increases the fibre/pith ratio in cane (except dry leaf when added to 44
weeks old cane), hard fibre % cane, pith % cane and total fibre in cane.
3.5.3.4 Effect of extraneous matter on fibre % cane
From Tables 3.14 – 3.16, it is evident that the addition of dry leaf and green leaf, but not
cane tops, to clean cane increases fibre % cane. These increases in fibre % cane due to the
presence of dry leaf and green leaf are calculated and shown in Table 3.17 for the four cane
varieties of three ages. These calculated increases compare favourably with the prediction
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