CANE SUGAR. 



11. The fact that the application of one particular element gives negative 

 results with respect to fertilization does not warrant the assumption that the 

 element in question may, with profit, be omitted as a component part of mixed 

 fertilizers. Applied with another element, the gains may be considerably 

 greater than could be obtained with the latter element alone. 



12. With both varieties the purest and richest juice was obtained from 

 the cane on the unfertilized area. In general, the plats receiving incomplete 

 fertilizers yielded juices of greater purity than those plats to which the three 

 elements were applied together. 



Later experiments have resulted in the same authority stating 7 : 



1. The profit resulting from the application of fertilizers or manures will 

 depend largely upon other factors than the chemical composition of the soil. 

 Providing certain plant food deficiencies represent the chief depressive influence 

 on crop yields, the response to appropriate fertilization will be commensurate 

 with the difference between the limitations exerted upon crop production 

 through lack of available plant nutrients and the limitations exercised by the 

 next restraining factor in order of importance after the material has been 

 applied. This latter factor may be physical, biological or climatic in character. 



2. The relative effects of different combinations of fertilizer materials on 

 the growth of sugar cane when these materials are added to a given soil will be 

 determined chiefly by 



(a) the extent to which their several ingredients directly or indirectly 

 lessen the deficencies of available plant nutrients ; 



(i) the extent to which they cause the bacterial flora to approach an 

 optimum balance for the regular production of sufficient 

 nitrates or assimilable nitrogen compounds, and 



(0) the degree and manner in which they produce physical changes in 

 the soil. 



3. Owing to the fact that a definite relationship exists between the 

 efficiency of a fertilizer mixture and the quantities and proportions in which 

 its ingredients are associated, due to biological, chemical and physical effects 

 which its component parts have in a given soil, variations in the composition 

 of the mixture beyond certain limits may materially influence crop yields. 



4. A more definite knowledge concerning the amounts and proportions of 

 fertilizer salts to use in a mixture for best results would on some soils yield 

 pronounced profits, while a lack of such knowledge may in some cases result 

 in a loss, especially when soluble salts are employed. 



5. The greatest loss from the use of improper mixtures of fertilizers is 

 apt to occur on acid soils, and in such cases considerable risk is involved from 

 the continued application of mixtures containing ammonium sulphate, sulphate 

 of potash, and acid phosphate, when lime dressings are not previously made. 



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