THE MANURING OF THE CANE. 



6. While the chemical and physical analysis of a soil will usually prove 

 of value in indicating the best cultural methods to follow in maintaining or 

 improving its fertility, and may also indicate in a general way certain of the 

 plant food deficiencies in given cases, it cannot afford definite information as to 

 the amounts or proportions of ingredients in fertilizer mixtures which will give 

 maximum returns. 



7. It is possible that the data from more extended field experiments with 

 a large variety of soils, when reviewed in connection with the comparative 

 analysis of the soils, using both, weak and strong acids as solvents, may indicate 

 a somewhat definite relationship between the analytical figures and the order 

 of importance which phosphoric acid and potash, should assume in cane fer- 

 tilizers in given cases. 



8. It would appear that analysis of soils, with more special reference to 

 their physical qualities, reaction and content of organic matter, nitrogen, and 

 more readily soluble lime, may, with due consideration of the water supply 

 and climatic conditions, be relied upon to indicate such manurial treatment as 

 will result in a profit, although they will not afford definite information as to 

 the weights and proportions of ingredients in fertilizer mixtures which will 

 result in maximum efficiency. 



9. Nitrogen is the most important element to be considered in the 

 fertilization of the sugar cane in the Hawaiian Islands, and when applied in 

 mixed fertilizers some risk of reduced efficiency is entailed if either the potash 

 or phosphoric acid (in the form of soluble salts) is made to exceed the weight 

 of this element. 



10. Unless through past local experience or carefully conducted field 

 tests, it has been definitely determined that a modified formula may be 

 expected to give greater yields, it is safer, when applying nitrogen, potash and 

 phosphoric acid in the form of soluble salts, to have the mixed fertilizer con- 

 tain even quantities of these elements, which are not to exceed 60 Ibs. per 

 acre in the case of each element. 



11. Field tests with fertilizers whose ingredients are mixed in varying 

 proportions will, if such experiments are accurately and scientifically conducted 

 through a sufficient period, give the most reliable information as to the best 

 manurial practice. Such experiments should be laid out in very long, narrow, 

 parallel and contiguous plats or strips, with the untreated check areas lying 

 immediately adjacent to the fertilized cane. 



12. The great importance of 'resting' fields in rotation on Hawaiian 

 plantations, and growing upon them leguminous crops is very clearly indicated. 

 This applies more particularly to the irrigated plantations, where the supplies 

 of organic matter are in the majority of cases becoming greatly reduced 

 through successive tillage operations in a comparatively arid climate, and by the 

 favourable conditions created for bacterial activity through regular irrigations 

 under uniformly high temperatures. 



