PLANT DISEASE 



From this analysis the variation or deteriora- 

 tion in the chemical properties of the soil under 

 cultivation is clearly shown. As further evi- 

 dence on this point of soil variation I quote 

 from Span's Encyclopaedia of the Industrial 

 Arts, Division V. p. 1864 : 



" The composition of cane soils may be 

 illustrated by two analyses by Dr. Phipson, 

 one (A) of a soil from an estate in Jamaica 

 under cane for the first time, the other (B) 

 from a Demerara plantation worked for more 

 than fifteen years consecutively " 



B. 



Moisture 



Organic matter and combined water 

 Silica and insoluble silicates 

 Alumina .... . . 



Oxide of iron ....... 



Lime . . . . * ... 



Magnesia . . . i . ... 



Potash . V ,. 



Soda . . . 



Phosphoric acid . ... . 

 Sulphuric acid . . . . 



Chlorine* 



Oxide of manganese, carbonic acid, 

 and loss in analysis . . " 

 Nitrogen in organic matter . 



12-25 

 i5'36 



48-45 

 13-80 

 672 

 0-99 

 0-29 

 o-n 

 070 



O'lO 



0-30 

 0-51 



0-42 



lOO'OO 



0-31 



1872 

 6-03 



68-89 

 2-50 

 2-60 



0-08 

 0-25 



O'lO 



0-09 

 0-03 

 0-03 



trace 

 0-68 



lOO'OO 



0-05 



* This quantity of chlorine is unusually high, which is accounted 

 for by the proximity of a salt spring. 



