THE MANURING OF THE CANE. 



sheet would give information as to the proper combination of manures to 

 apply ; this idea demands that for any plant there is one particular ash 

 analysis which is most suited for it. The variation, however, is so great that 

 no ' best ash ' for the cane can be obtained, and this captivating hypothesis 

 breaks down on subjection to scrutiny, or rather is not supported, as regards 

 the cane, by sufficient evidence. It is conceivable, however, that an ash 

 analysis showing a low proportion of, say, lime might point to a deficiency of 

 available lime in the soil ; on the other hand a deficiency of lime in the soil 

 might be reflected in small crops rather than in a low percentage of lime in the 

 ash. 



Connected with this subject is the " Analysis of the Soil by Means of the 

 Ash "; this point has been recently studied by Hall 18 , who thus summarizes 

 his results, obtained of course in a temperate climate (England) but none the 

 less generally applicable : 



1 . The proportion of phosphoric acid and of potash in the ash of any given 

 plant varies with the amount of these substances available in the soil, as measured 

 by the response of the crops to phosphatic or potassic manures respectively. 



2. The extent of the variation due to this cause is limited, and is often no 

 greater than the variations due to season, or than the other variations induced by 

 differences in the supply of non-essential ash constituents soda, lime, &c. 



3. The fluctuations in the composition of the ash are reduced to a minimum in 

 the case of organs of plants, which, like the grain of cereals or the tubers of 

 potatoes, are manufactured by the plant from material previously assimilated. 



4. The composition of the ash of the cereals is less affected by changes in the 

 composition of the soil than is that of root crops like swedes and mangels. 



5. The composition of the ash of mangels grown without manure on a particu- 

 lar soil gives a valuable indication of the requirements of the soil for potash manuring. 

 Similarly the phosphoric acid requirements are well indicated by the composition of 

 the ash of unmanured swedes, though in this case determination of the citric acid 

 soluble phosphoric acid in the soil gives even more decisive information. 



6. Pending the determination of phosphoric acid and potash 'constants' for 

 some test plant occurring naturally on unmanured land, the interpretation of soil 

 conditions from analyses of plant ashes is not a practicable method by which 

 chemical analysis of the soil can be displaced. 



The Utilization of Waste Products as Manure. In order 

 to estimate the quantity and distribution of the ash and nitrogen brought into a 

 factory, the writer made the analyses detailed in the Tables below, for a 

 factory working up to 50,000 tons of canes. The process used in the factory 

 was dry double crushing and simple lime defecation ; no sulphur or phosphoric 

 acid was used. In Table I. are given analyses of the ash of various products ; 

 in Table II. the total amounts entering the factory per 1000 tons of cane; and 

 in Table III. the distribution of the nitrogen and the constituents of the ash 

 over all the factory products, the amount in the canes being put equal to 100. 

 Inspection of these tables will show that on this particular estate the amount 

 of potash in the canes was abnormally high, and that of the lime equally low, 

 the phosphoric acid being present in moderate quantity. 



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