CHAPTER VI 



The Manuring of the Cane 



The early growers of the cane in the tropics carried with them the principles 

 -of faiTn practice developed by years of experience in the older countries, 

 :and the use of bagasse, bagasse ashes, factory refuse and stable manure 

 was practised from very early times. 



Very soon after the use of artificial manures became general in Europe, 

 ■attention was directed to their use in cane culture. The earUest reference 

 to their use comes from British India and is due to T. F. Henley^ ; this is 

 followed by a communication of Boj er^ dealing with practice in Mauritius. 



The earliest detailed experiments are those made in 1S57-59 by Krajen- 

 brink^ in Java, followed by others in Guadeloupe by de Jaubrun* made at 

 the instance of the eminent French agronomist, Georges Ville. A third 

 •early series was those made in Louisiana by Thompson and Caje and reported 

 by Goessmann.^ Since these early experiments a very great mass of ex- 

 perimental data has accumulated, due to the work that has been cariied 

 on in nearly all districts that gr.,w the cane as a staple product. The results 

 of some of these experiments are collated below. 



British Guiana. — Scard,^ as the result of an extended series of experiments 

 on the Colonial Company's estates in British Guiana, concluded : — 



" r. That lime used by itself gave a small pecuniary gain. 



2. That lime associated with manures gives an increase sufficient to pav 

 for itself only when used with larger (2 cwt.) quantities of soluble nitrogen, such as 

 sulphate of ammonia. 



3. That of nitrogenous manures, sulphate of ammonia at the rate of 2 cwt. 

 per acre gives the best results. 



4. That ground mineral phosphate appears to give an increased yield compared 

 with superphosphate. 



5. That guanos, especially in conjunction with lime, fall far short of ammonia 

 in beneficial effect. 



6. That an increase of phosphoric acid over the minimum employed (168 lbs. 

 per acre) fails to give satisfactory pecuniar}' results. 



7. That neither lime nor manures produce any perceptible difference in 

 the purity of the juice but only affect the weight of cane." 



Harrison' concluded as a resume of work on cane manuring : — 



" I. That the weight of cane is governed by the amount of readily available 

 nitrogen either naturally present or added as manure. 



2. When applied in quantities containing not more than 40 to 50 lbs. nitrogen 

 per acre, sulphate of ammonia and nitrate of soda are equally effective manures 

 on the majorit}^ of soils, but that when the unit of nitrogen is of equal money value 

 it is more economical to supply the former. Dried blood and similar organic 

 manures in which the nitrogen only slowly becomes available are distinctly inferior 

 sources. 



3. Under ordinary conditions of soil and climate and the usual range of 

 prices for sugar, it is not advisable to supply more than 2 cwt. of sulphate of 

 ammonia or 2| cwt. of nitrate of soda per acre. 



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