THE CUBA RE V I E W 



Fertilization of Cane Sugar in Cuba 



By Alvin Fox, B. Sc, Ph. D. 

 Agric. Botanist 



The secret of a profitable sugar industry lies in economically growing robust cane, 

 rich in sugar; and no soil is so rich as to continue year after year to grow large and 

 remunerative crops — unless the plant food removed by the crop be returned in thd 

 form of fertilizers. Those sugar countries which are growing the largest crops of cane 

 per acre are the most prosperous. A careful study of their practices teaches that they 

 obtain success and wealth by thorough preparation of the soil, judicious fertilizing, in- 

 telligent cultivation (including irrigation when required), and an elimination of rattoons 

 as soon as their yields drop below a profit-producing quantity. 



The world's experience is that no one crop of cane can be grown continuously and 

 profitably on the same unfertilized soil, no matter how rich it was at the beginning. 

 Sugar cane is a most exacting as well as soil exhausting crop, and necessitates the feeding 

 and so restoring of those soils to their former fertility, which had fallen in annual 

 yield from 40 tons of cane in the beginning to 20.18 and 16 tons. The average yield 

 of cane today in parts of Cuba are about 18 tons per acre, as against about 46 tons 

 per acre during the earlier years of the sugar industry. Further on, after showing by 

 analysis of virgin soils and those continually cropped with cane, a loss of 31 per cent 

 nitrogen, 42.2 per cent potash, and 37.2 per cent lime in the latter. 



Their immediate yielding power has been seriously impaired, but by more modern 

 methods of cultivation, rendering available the reserve stores of plant food, and by 

 returning to the land those elements which have been and are being removed, the pro- 

 ducing power can be restored. Intelligent cultivation, and a judicious use of fertihzers 

 can, without a doubt, restore the original producing power to these soils, and obtain 

 40 tons of cane per acre. More than that, here as elsewhere, by the application of 

 scientific resources and intelligence, better and larger crops can be grown than those 

 first produced by the virgin soil. 



Again, sugar cane, like every other plant, needs for its growth a number of chem- 

 ical substances, but as most natural soils supply a large part of these ingredients in 

 , abundance, it is necessary here to consider only those which, in cultivated soils, are 

 frequently more or less lacking. These are potash, phosphoric acid and nitrogen, and 

 their relative relation to the cane crop has been the subject of important investigation 

 and study by the scientific agricultural botanist. 



It was found that the absence of either of them was fatal to the life of the cane 

 plant, and that, with an insufficient supply of any one of them, the plant grew slowly; 

 but when all were present in ample quantities, it grew rapidly. 



The skilled cane-grower ascertains what his soil requires in the w^ay of potash, phos- 

 phoric acid or nitrogen, or all three of them, in order to produce strong, healthy plants, 

 and then supplies that in which it is deficient. 



The object of the manufacturer of commercial fertilizers is to meet the exact needs 

 of the sugar planter, and so, while he sells each one of these, separately, he also com- 

 pounds them, by means of modern machinery, into what are styled "complete fertilizers," 

 which are mixed and blended to suit the certain soils and the needs of the cane crop to 

 be grown profitably. 



Different forms of the same chemical may differ in action and effect, so form 

 itself is to be considered in an economical administration of a sugar estate. 



Where stable manure can be had, it is useful to the cane, especially for its nitrogen; 

 but it is comparatively poor in potash and phosphoric acid, both of which must be 

 supplemented in proper proportion if a full benefit be expected. 



