THE MANURING OF THE CANE. 



In more than one cane growing district all manures intended for use on 

 plantations are analysed and controlled at the Experiment Stations now 

 generally considered a necessary adjunct to large cane growing districts; this 

 work but seldom falls to the estate chemist. 



Taking the value of nitrogen in sulphate of ammonia as 100, the 

 following are the average values adopted for other constituents ; it should be 

 mentioned, however, that no uniformity obtains as between different districts. 



Nitrogen in ammonia sulphate 100 



Nitrogen in nitrate 90 



Organic nitrogen . . 100 



Water soluble phosphoric acid 25 



Citrate soluble phosphoric acid 25 



Insoluble phosphoric acid 10 



Potash in sulphate 30 



Potash in chloride 25 



The valuation of materials such as seed cakes, tankage and packing house 

 refuse depends very largely on the degree of fineness of the material. This 

 also applies to basis slags, which are usually sold under a guarantee of fineness. 

 A slag 80 per cent, fine means that 80 per cent, of the material will pass 

 through a sieve with a mesh of 250 wires to the lineal inch. 



Lime in Connection with Cane Growing. A. study of the 

 analyses of the ash of the cane cannot lead to the conclusion that the cane is a 

 calciophile plant, and Harrison 3 in his resume of twenty-five years' experimental 

 study of the manurial requirements of the cane has come to the same conclusion. 



The benefits that follow the application of lime in many districts where the 

 cane forms the staple crop must not then be considered as due to specific action 

 of this material on the cane, but as due to its general effect in amelioration 

 of the soil. 



The action of lime may be briefly summarized : 



1 . Correction of acidity in the soil, whether due to an excess of organic 

 matter, or due to long continued application of ammonia salts. 



2. Amelioration of the physical condition of heavy clays. 



3. Rendering potash available. 



It is now generally considered better practice to apply moderate applications 

 of lime, say lOOOlbs. per acre, every five or six years, than to put on heavier 

 applications less frequently. This is the general rule in the Hawaiian Islands, 

 larger applications being only made on a few plantations possessing a distinctly 

 sour soil with much organic matter. However, some heavy clay adobe soils 

 have been treated there with success with as much as fifty tons of coral sand to 

 the acre ; this procedure recalls the system of marling once so prevalent in 

 English agricultural practice. 



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