THE SOILS OF THE CANE-GROWING REGIONS 



77 



drainage notwithstanding being excellent. The depth of the soil is from two> 

 to twenty feet, and it varies in character from a fine sandy loam to silt. 



The soils are of the alkali type, and especially towards the sea contain 

 considerable quantities of water-soluble chlorides, sulphates and carbonates. 

 The soils are well supplied with plant food, the lime, much of which is present 

 as carbonate, being very high compared with that found in the cane soils 

 of other districts. The total phosphoric acid and potash are also good. 

 The nitrogen is very variable, dependent upon the time the soil has been in 

 cultivation, the water supply, the class of weeds, and the amount of flood 

 waters required to cover the fields. The humus and organic matter are both 

 higher than would be expected in the soils of an arid district. 



Sedgwick gives thirty analyses of soils from the Cartavio estates, from 

 which the present writer has calculated the averages. The analyses are 

 presumably made by the official American method. 



Maximum Minimum Mean 



Insoluble matter 



Ferric oxide . . 



Alumina 



Lime 



Magnesia . . 



Potash 



Phosphoric acid 



Sulphuric acid 



Humus 



Potash sol. in i per cent 



citric acid 



Phos. acid sol. in i per cent, citric acid 



7 l 



6- 



2- 

 O' 



O' 



I- 



O' 



o- 



50 



10 



75 

 57 

 60 



88 

 84 



0258 

 0630 



49-22 

 4-00 



0-65 



0-23 



0-16 



o- 16 



0-05 



0-42 



0-0050 



0-0081 



63' 

 5 



4' 



2' 

 O- 



O' 

 O' 



I- 



O' 

 O' 



i 



98 



92 



I 



26 



0121 

 0337 



It is interesting to compare these soils with the equally productive ones 

 of the Hawaiian Islands. These soils are " acidic," and contain much more 

 silicates insoluble in hydrochloric acid than do the " basic " soils of Hawaii,, 

 the latter containing much more ferric oxide, and it is as a consequence of 

 this that the availability of the phosphoric acid in the Hawaiian soils is so 

 much less than in the Peruvian. The high content of the Peruvian soils in 

 lime is, too, a factor which should contribute to their continued fertility. 



Philippine Soils. Up to the present no extensive survey has been made 

 of the soils of this district, which may in time become one of the great sugar- 

 producing areas. A large number of Luzon soils have, however, been analysed 

 by Cox and Arguelles. 25 They are described as being clays or clay loams, 

 and, from their analysis, should be of great potential fertility. As an average 

 the lime exceeds I per cent., the phosphoric acid and potash approximate 

 to 0-3 per cent., the nitrogen averaging over o-i per cent. Conditions very 

 similar to those obtaining in Java would be expected here. 



Queensland Soils. The sugar cane soils of Queensland have been sub- 

 jected to survey by Maxwell. 26 He divides the soils of Queensland into 

 three districts, the Southern or Bundaberg, the Central or Mackay, and the 

 Northern or Cairns. 



Dr. Maxwell subdivides the soils of the southern district into four classes : 

 the red soils, derived from true basaltic lavas ; the mixed dark and light red 

 and yellow-red soils, derived partly from basaltic lavas and partly from 

 eruptive action upon other rock formations ; soils more rather than less of 

 sedimentary origin ; and soils derived exclusively from older rock formations. 



