Vol. IX. No. 213. 



THE AGRICULTURAL XEWS. 



195 



cultiv.ation. The same consideration shows the necessity 

 for care and caution in applying manures, at any rate to 

 soils containing little lime. Nitrate of soda reduces 

 the condition of such soils by becoming converted 

 into carbonate of soda which lowers the power of the 

 clay particles to form floccules. The remedy for 

 this is the use of superphosphate; a preventive meas- 

 ure is to apply some of the nitrogen in the form of 

 sulphate of ammonia by mixing this with the nitrate 

 of soda. Common salt and potash manures also cause 

 injury to the tilth, because they increase the alkalinity 

 of the soil through the influence of the lime in it. To 

 prevent this occurrence, where it is necessary, these 

 manures should be accompanied by superphosphate.-^ 



The broad, practical interpretation of these facts is 

 that a properly treated soil will remain productive and 

 if, as is generally the case, it is e.xpedient to increase 

 its productivity by the use of artificial manures, the 

 kinds and quantities of these must be decided by con- 

 siderations of the e.xtent to which their use will be profit- 

 able, and of the effects that they are likely to produce, 

 in relation to the te.Kture of the soil. 



PRODUCTION OF SEEDLING CANES 



IN JAVA. 



The following is a translation of part of an article 

 which appears in the Jnurnal d' Afjriialtvire Tropicale, 

 for January 1910, which is an abstract of a paper pre- 

 sented by the late J. B. Kobus at the last International 

 Congress of Applied Chemistry, held in London. The 

 experiments described were carried out at the East 

 Java Experiment Station: — 



The seed of the cane began to take a po.sition of economic 

 importance in the Java sugar industry when, following upon 

 the first researches of Dr. Soltwedel in .Java, of Messrs. 

 Harrison and Bovell in the West Indies, Kobus took up the 

 sj'stematic work, which rapidly led to practical results, 

 thanks to the valuable aid which he received from jilanters 

 in the island. 



In 1894, Bouricius succeeded in making the first cross 

 between the Cheribon and the Morte de Fiji, which under 

 the name of No. 247, occupied 35 per cent, of the planta- 

 tions in Java. It was during the course of the same year 

 that Dr. Wakker, after much patient research, gave an 

 explanation as to why the greater number of canes were 

 incapable of being self-fertilized: this was found to be owing 

 to constitutional defects in the flowers. 



The two seedling canes that are chiefly feund in cultiva- 

 tion at present, though they have certain advantages, are not 

 absolutely perfect in type. One, No. 247, is attacked by 

 Sereh; the other, No. 100, does not grow well on different 

 kinds of soil. 



Kobus did not at all despair of attaining entirely satis- 

 factory results, and continued his researches accurately, accord- 

 ing to a plan which had been drawn up methodically. He tried 

 to distinguish characters that were more especiallj- marked: 

 particularly lesistance to disease and richne.ss in sugar: 



at the same time he conducted a microscopic examination of 

 the flowers in order to make certain that the structure of the 

 central organs was normal. Evidence of the fertility of the 

 pollen is obtained by the aid of a solution containing iodine. 

 In order to prevent interference by foreign pollen, the arrows 

 which are being cros; -pollinated are confined in a cover of fine 

 gauze. A single arrow is sufficient when self-pollination is 

 being affected; but it is necessary to bring two arrows together 

 under the same cover in order to ensure an effective 

 crossing. In the last case, the female element is furnished, 

 in preference, by a variety normally possessing sterile Dollen — 

 a phenomenon which is generally shown by canes of high sugar 

 content. It has been ascertained that the dehiscence of the 

 stamens of the sugar-cane takes place early in the day, most 

 often between four and six o'clock, rarely later than nine 

 o'clock, in the morning, and that the opening of the flowers 

 may easily continue during five or six days. The drying up 

 of the male arrow is prevented, during this lapse of time, by 

 taking care to remove these inflorescences from the cover, for 

 the purpose of keeping them, with the base of the stalk in 

 water, until the early hours of the morning. In spite of these 

 precautions, checks have been experienced, which physiologists 

 have not yet succeeded in explaining satisfactorily. 



The parent canes which are intended to take part in 

 cros.s-pollination are submitted, during the preceding year, to 

 a most rigorous chemical selection, prompted by differences of 

 10 per cent, in sugar and 20 per cent, in weight which have 

 been observed between seedlings of the same varieties but 

 from more or less rich parents. 



The method described by M. Kobus is strictly followed 

 at the East Java Experiment Station, where 16,000 to 32,000 

 seedlings are raised in this way every year. Unfortunately 

 the greatest uncertainty exists as to the results, which are 

 disappointing on most occasions. In the hope of lessening 

 this considerable loss, the idea arose of sowing the seeds from 

 successive crossings between four or five ditt'erent varieties; 

 the first trials made of this new method brought about greater 

 success than when one crossing was employed. 



At the first harvest, the seedling canes are submitted to 

 a selection which is not less severe than that which took place 

 before they were obtained. Those are taken out first which 

 are obvirmsly inferior in appearance; the others are analysed 

 with a view to planting cuttings of those, only, which have 

 a completely satisfactory sugar content. In 1907, the minimum 

 of richness permitted had to correspond to a yield of 4 tons of 

 sugar to the acre; at the present time, a minimum of 7 tons 

 is required. Under these condition.s, the double test in the field 

 and in the laboratory only allows the survival, for replantation, 

 of a feeble proportion, consisting of twenty-five canes in 

 10,000 seedlings. This average is reduced by two-thirds 

 during the following year; in the fourth year, the few seedlings 

 which have succeeded throughout this long series of special 

 trials are cultivated in the experimental field, together with 

 the best varieties that have been obtained. Those among 

 them which undergo the comparison to their advantage are 

 definitely classed, and propagated in sufticient quantity to 

 permit of their distribution to those planters who are wishful 

 to make trial of them. 



The systematic application of this eminently scientific and 

 rational method has saved the sugar industry of Java, on the 

 eve of its suflering serious damage through several threaten- 

 ing fungus diseases; it has raised the yield of sugar from 

 one of 2i tons in 1SS7 to one of 4i tons in 190S; in a word, 

 it has contributed to the great development of cane planta- 

 tions, and to their prosperity. It is believed that these results 

 are amply sufficient for calling attention to the work accom- 

 plished by Kobus and his worthy fellow-workers. 



