Vol. XIII. No. 321. 



THE AGRICL'LTUEAL NEWS. 



259 



SUGAR INDUSTRY. 



RECENT PROGRESS IN THE CULTIVA- 

 TION OF THE SUGAR-CANE. 



All abstract of the ruport of tliu C'uiiimitU-L- on tlit- culti- 

 vation and fertilization of uninigated ]jlantatioii.s appointed 

 by the Hawaiian Sugar Plaiiter.s' Association has just been 

 issued and is abstracted in the International Sui/nr Jownal 

 for -July 19U. 



Dealing first with the a[)plication ol manures, it is stated 

 that on one plaTitation it used to he the custom to apply 

 fertilizers in large amounts at a time, but this year (1913) 

 the dose has been reduced and given more often, with good 

 results. The ratoons, having a larger root formation, were 

 alile to stand the larger (|uantity to ad\antage. Whereas in 

 jirevious years it was customary to gi\e a first dose of -^(10 Ih. 

 to jilant canes, the first ai)j)lication has now been reduced to 

 lialf that amount, namely 2">0 tli. with an additional •")(!( I B). 

 on hilling u]). It is being found useful to apply tankage at 

 the time of planting and in treating ratoons after the plant 

 canes are taken off as much as possible of the top.s and 

 trash is ploughed in to increase the humus. 



The subject next dealt with in this summary is that of 

 spraying machines for weed destruction. The Director of the 

 Station originatefl the idea that a mule-drawn ai)i)liauce 

 consisting of a spraying outfit so constrncted that the liquid 

 would be prevented from coming into contact with the canes, 

 while playing on the middles l)etween the rows, would [jrove 

 ill! ertective weed destroyer when charged with a destructive 

 solution. An effective spray has been found to be a very 

 weak solution of arsenite of soda. After some preliminary 

 oxiieriments, a s[)rayer of simple construction which gave 

 .satisfactory results, was designed, and from small trial tests 

 namely, 1.5 to 20 acres, it has been shown that the methixl 

 might lie applied on a large scale thereby reducing the present 

 cost of weed destruction to less than one-half of the present 

 amount. It remains, however, to lie jiositively shown that 

 no harm results from the application of arsenic to the soil. 

 The application of 6 to 7 ft), of arsenic per acre to a ferrugi- 

 nous soil in a wet climate should not give rise theoretically to 

 any harmful results. The cost of the ajjplication per acre for 

 labour and chemicals is calculated to lie approximately 6.5c. 

 A fairly detailed account of the machine is given in the 

 issue of the International Su^/ar ■Journal, from which this 

 information has been obtained. 



The methods of soil cultivation in Hawaii are largely 

 concerned in principle, at least on the unirrigated lands, witli 

 the increase of humus by ploughing in organic matter. 

 Ploughing in or 'rotting back' the trash on the ratoon fields 

 has been practised sometimes with good results and at other 

 times with apparently the adverse effects: on the whole, the 

 practice together with liberal liming is beneficial, provided 

 that the fields are reasonably clear of injurious pests and 

 disea.ses. 



The view is expressed that there is no crop, leguminous 

 or otherwise, that is equal to cane as a .soil enricher, provided 

 advantage be taken of all the residues left in the field after 

 the crop has been carrieil. This, of course, is more theoretical 

 than practical because of the difficulty of turning in the trash 

 in round-ploughing for planting; but it is said that this has 

 been overcome by employing the Spaulding deep-tiller plough. 

 'If it were possible to store the heavj- piles of trash left by 

 the crop between the rows, the pile would act as a blanket 

 and prevent evaporation. With the e\er increasing speed at 

 which water levels are sinking in the district, it behoves the 



irrigator to cast about for some means to make a little go- 

 a long way: and it may lie predicted that by persisting in 

 rotting back all residues, in ten years as good, if not better 

 crops will l:ic grown with 50 per cent, of the water at present 

 used'. 



Labour economy in field operations is dealt with next 

 and in comiexion with cutting it is said that there are times 

 when liurning does not represent true economy. It is main- 

 tained that cutting can be accomplished much more economi- 

 cally when cane has had a stripping. It is found also tliat 

 stripped cane is always less harmed by burning than unstripped. 

 'Stripped leaves being bedded down and invarialily more or 

 less moist, burn more slowly and therefore less intensely. 

 In fact there is frequently a con.sideralile amount of trash 

 left unburned, while a burn on unstripped at the same time- 

 would make a clean sweep.' 



A NEW MANURE: ELECTRO-POTASH. 



In the Monthly Bulletin of Agricultural Intelli- 

 f/ence and Plant Diseases for May 1914, is published 

 the following information concerning the exjjerinients 

 can-ied out by H. G. Soderbaiun at Stockholm wdth 

 regard to this new fertilizer. 



The price of German potassic salts is much higlier in 

 Sweden than in other countries, and the writer reviews all 

 the trials which have been made to utilize felspars, or other 

 potassic rock constituents in Sweden, for the preparation of 

 potassic fertilizers. 



Up to the present all attempts have failed, but a new 

 method recently invented by two Swedish workers, 

 A. Lindlilad and L. Yngstiiim appears promising. The 

 raw material is a common rock in Central Sweden called 

 'leiJtite' or 'eurite' similar in chemical composition to a gneiss 

 or felspar, and may contain up to 1 1 per cent, of potassh. 

 Leptite is niLxed with coal and iron filings, and treated 

 in an electric oven provided with carbon electrodes at 

 a temperature of 1,800'C. approximately. At this tem- 

 perature the silicic acid in the rock is partially reduced to 

 silicon; this combines with iron to form a silicic iron, which 

 collects in the bottom of the oven under a layer of slag 

 consisting chiefly of potassium and aluminium silicate and 

 more soluble than the silicates in the original leptite. The 

 slag, when cold and finely ground forms a grey powder and i.s 

 sold under the name of electro-potash ('electrokali'). 



The principal product, silicic iron, is easily disposed of 

 as an alloy for various metallurgical uses, but in order that 

 the manufacture should prove remunerative, a market mu.st 

 also be found for the electro-potash. The latter was 

 analysed at the Central State Experimental Station and was 

 shown to contain about 1 1 per cent, of potash, of which 

 10 per cent, is soluble when the material is treated on the 

 water bath with 20 per cent, hydrochloric acid, while shaking 

 the material with 2 per («nt. hydrochloric acid for twelve 

 or twenty-four hours dissolved out 6 and 6'5 per cent, 

 re.spectively. 



The writer carried out some pot cultures in which the- 

 new manure was tested against sulphate of pota.sh, both being 

 supplied at the rate of 1 80 ft. of potash per acre. The 

 results show that the electro-iiotash pots yielded 78 per cent, 

 of the crops obtained on the sulphate of potash pots which 

 is fairly satisfactory as a first experiment. Moreover as it 

 was found jiossible to increase the solubility of the slag 

 during the year 1913, it does not seem iniproliable- 

 that further trials will yield still better results, so that this 

 new method of using native resources for fertilizing the soil 

 may prove an economic poss 



