100 CHAPTER VI 



of leaves, tops and roots, which normally remain on the land. In the case 

 of the phosphoric acid, however, the division between stalks and residues is 

 approximately equal. As regards the material entering the factory, 70 

 per cent, of the potash is found in the molasses, 20 per cent, in the sugars 

 and 10 per cent, in the bagasse. Of the phosphoric acid, 80 per cent, appears 

 in the press cake, 10 per cent, in both bagasse and molasses, and only a very 

 small quantity in the sugars. Of the nitrogen, 60 per cent, is accounted for 

 in the press cake, 25 per cent, passes to the molasses, 10 per cent, is found 

 in the bagasse and 5 per cent, in the sugars. That quantity which appears 

 in the molasses is mainly in amide form, the albuminoid nitrogen being pre- 

 cipitated in the defecation process. Of the Hme the press cake contains 

 50 per cent, more than is introduced with the stalks, most of the balance 

 going to the molasses. Based, however, on the whole amount of matter 

 taken from the soil, only 20 per cent, of the potash is found in the molasses, 

 5 per cent, in the sugars, 3 per cent, in the bagasse, the balance, approximately 

 70 per cent., appearing in the leaves, etc. Of the total amount of phosphoric 

 acid, half remains in the leaves and half is found in the factory products, 

 the press cake accounting for the major portion. Similarly, the leaves, etc., 

 contain 70 per cent, of the nitrogen, 60 per cent, of the remainder being found 

 in the press cake, with most of the remainder in the molasses. It follows, 

 then, that the sugar cane cannot be considered an exhaustive crop since so 

 much of the material removed from the soil is- actually returned or capable 

 of being returned thereto. 



The agricultural economy of a plantation is influenced bj' the way these 

 crop residues are treated. Considering first the material contained in the 

 stalks, the greatest possible source of loss is in the molasses. Practice 

 differs as to its disposal. In Cuba nearly always, in Java and in Hawaii 

 very often, the molasses are sold as a part of the crop, or failing to find a mar- 

 ket are run to waste. Prior to 1914, the price of molasses in Cuba at the 

 plantation w^as about 2| cents per U.S. gallon, or $4.00 per short ton, and 

 equivalent prices prevailed elsewhere. A short ton of molasses will contain 

 on an average 80 lbs. of potash, which at 5 cents per lb., the then price for a 

 lb. of potash in high-grade material, exactly equals the price paid for the 

 molasses sold nominally on its content of sugars. Considered, then, from 

 the point of view of the agricultural economist, the sale of molasses off the 

 plantation should be condemned. The value of the potash thus annually 

 removed is very great. The world's production of cane sugar now (1919) 

 amounts to about 13,000,000 tons, and the molasses corresponding to this 

 quantity will contain about 130,000 tons of potash of value $13,000,000 

 at pre-war prices for the potash alone, together with another $4,000,000 

 on account of the nitrogen. 



The most natural method of its utilization would be in the production 

 of alcohol, with the recovery and return to the soil of the distillery " slop " 

 or at least with the recovery of the potash, as is often done in beet distilleries 

 on the continent of Europe. In some districts, notably Demerara, Peru 

 and Natal, the distillery often forms an integral part of the plantation, 

 but generally only the manufacture of alcohol is considered, the waste 

 product being neglected. Many years ago, however, a Demerara plantation, 

 " Montrose," installed a " lees " irrigation plant, which unfortunately only 

 operated a short time prior to the destruction by fire of the distillery. 

 Some attempt is, however, made there to dig out periodically the '• lees " 

 pond, and return the bulky evil- smelling material to the fields. Possibly 



