Vol. X. No. 247. 



THE AGRICULTURAL NEWS. 



32.3 



SUGAR INDUSTRY. 



SUCROSE AND POTASH IN CANE JUICE. 



The InternatioHal Swjar Journal for August 1911 

 contains a paper by H. C. Prinsen Geerligs, which is of 

 much interest as it demonstrates the existence of a relation 

 between the sugar in the juice of the cane and its content 

 of potash. 



It is first pointed out that the observation has been 

 made several times to the eft'ect that, although the quantity 

 of exhausted molasses obtainable from a given variety of 

 cane varies considerably, yet the composition of the 

 molasses, and especially the amount of potash in it, does not 

 ditt'er much, from sample to sample. Cane juice of a high 

 purity gives exhausted molasses very similar in its composi- 

 tion to that from juice with a very low purity. 



Further, analysis makes it evident that the ratio of 

 potash to dry substance in exhausted molasses varies little, 

 although the quantity of raolas.ses obtainable exhibits con- 

 siderable differences. 'For example, in the case of juice of 

 75 purity yielding 2-| times the quantity of molasses which 

 is produced by juice of 90 purity, the potash content of the 

 latter is by no means 2.', times that of the former ; and this 

 is only what may be expected if both had contained at the 

 outset the same ratio of potash to dry substance content. 

 As, however, this potash content does not ditier, we are 

 compelled to admit the fact that, generally, a cane juice of 

 low purity is more charged with potash salts than a juice 

 having a high quotient of purity.' This, combined with the 

 fact that the purity is infiuecced mainjy by the glucose 

 content, leads to the conclusion that the glucose in a ripe 

 cane is accompanied by a fixed proportion of potash salts, so 

 that the latter keep back in the cane juice a quantity of 

 glucose which does not disappear during the ripening of the 

 cane, and thus the quotient of purity is lowered. If the 

 potash salts possess such an action, a ripe sugar-cane with 

 a high potash content must contain a high percentage of 

 glucose. Actual investigations have shfiwii this to be true 

 in the case of the beet. 



The matter is complicated by the fact that differences 

 in purity are brought about by the soil conditions, climate, 

 the manures employed and the variety of cane; the degree of 

 maturity of the cane also entails differences which are likely 

 to cause confusion. The work of the author, combined with 

 the results of others, shows that there is no perceptible 

 change in the content of potash in the juice while the cane 

 is ripening. It thus follows that if there is any relation 

 between the proportion of potash and that of glucose, it must 

 be correlated with what is termed the natural glucose in the 

 cane, namely that which depends on the variety and condi- 

 tions of climate; but not with what is called the accidental 

 glucose, which is present through imperfect maturity or 

 over-ripeness. 



In the investigations, analyses were made of juices from 

 estates dealing with canes possessing a juice with a high 



purity, and similarly with those grinding canes with a low- 

 purity. In the same way the experiments were extended to 

 different varieties of cane, choosing for comparison those 

 giving juice of the highest purity and those in which this was 

 very low. In the result, the indication was obtained that, in 

 the case of rich and pure canes, the juices contained little 

 potash; whereas where the purity of the juice was low, large 

 quantities of potash were always found. The same was 

 demonstrated to he true of the varieties chosen to exhibit 

 large differences in purity. 



It therefore follows that canes posses-ing the largest 

 power to absorb potash from the soil gave juice with the low- 

 est purity, and that conversely, the available sugar was largest 

 in amount from canes absorbing the least potash. It is, 

 naturally, not intended that the.se statements should discour- 

 age the employment of potash manures among planters, for 

 these are necessary in order that the plant may have an 

 adequate supply of its essential food bodies in the soil. 



It is pointed out that while .sugar-cane seedling produc- 

 tion and selection have given canes with a larger weight, 

 there has been no increase in the sugar content, but rather 

 a decrease in many instances. The practical import of the 

 investigations is then expressed, namely that more attention 

 should be given in seedling cane production to the sucrose 

 sugar content, and that a useful indication of this is afforded 

 by the determination of the extent to which potash salts are 

 present in the juice. 



Susrar-cane Seedling D.1135 in New South 



Wales. — A bright, light purple-coloured cane, introduced 

 by the Colonial Sugar Refining Company, from Fairymead, 

 Queensland. 



So far as growing trials of this cane have progressed, 

 D. 11 3.5 proves best as a two-year-old plant cane, but is of 

 uncertain sweetness, and somewhat difficult to trash. As 

 a ratoon cropper, it is reported to develop poorly. It is an 

 exceedingly straight grower, carries a dark olive-green leaf 

 of attractive appearance, and has few dead stalks as a two- 

 year-old crop. 



On the Richmond River, it is questionable whether this 

 cane is likely to prove the continued success that D.113.5 has 

 been found to be in other parts of the State. Here its sugar 

 density appears to be greatly influenced by weather and soil 

 conditions. In this respect it cannot be relied upon, as can 

 the two more largely grown varieties, ^lalabar and Mahona. 



As the true character and value of D.1135 have not as 

 yet been fully demonstrated, this cane should be given 

 a further and more extended trial. (The Aiiricnltural (razette 

 of Km' South Ilrt/es, Vol. .X.XII, p. 516.) 



A report from Montserrat states that ample rains have 

 fallen during September, throughout the island, and that the 

 outlook for the cotton crop has improved considerably. It is 

 thought that this will not be quite up to the average, but as 

 the area in cotton cultivation has increased, the total output 

 will be fairly large. Cotton-picking has commenced at least 

 a month earlier than it did last year. In the districts that 

 have suffered severely from drought, as well as in some others, 

 leaf-blister mite is more prevalent than it has been for many 

 years. The cotton worm has not caused much trouble, while 

 angular leaf spot has not been present to the extent of last 

 year, and the flower bud maggot has not been reported. 



