CANE SUGAR. 



give the mean composition of the soils of the Hawaiian Islands based on 397 

 analyses, by the American (United States) official method* : 



Phosphoric 



Lime. Potash. Acid. Nitrogen. 



Island. Per cent. Per cent. Per cent. Per cent. 



Oahu '411 .. '348 .. '269 .. '119 



Kauai '504 . . '358 . . '237 . . '246 



Maui .. -691 .. "401 .. '200 .. '222 



Hawaii '833 .. '353 .. '321 .. '388 



Whole Group . . . . '693 . . '366 . . -268 . . -290 



Maxwell also determined the solubility in 1 per cent, of citric acid, of 

 lime, potash and phosphoric acid in a number of typical soils. The averages of 



his results (calculated by the present writer) are as below : 



Phosphoric 



Lime. Potash. Acid. 



Per cent. Per cent. Per cent. 



Highest -281 .. -084 .. -0125 



Lowest '030 .. '009 .. '0012 



Average '113 .. '033 .. -0043 



The low amount of available phosphoric acid in proportion to the great 

 amount actually present is due to the accompanying ferric oxide, which is 

 present in very great amount. Hilgard, in examining Hawaiian soils, calls 

 attention, too, to the high content of phosphoric acid " exceeding all others 

 on record," and, at the same time, emphasizes the action of ferric oxide in 

 rendering the phosphoric acid unavailable. 



Other Hawaiian soils examined by him, while containing large amounts 

 of nitrogen, were yet ' nitrogen hungry.' The percentage of nitrogen in the 

 humus of these soils was low, and Hilgard is inclined to attribute more 

 importance to the nitrogen in the humus than to the total nitrogen. Mr. C. 

 F. Eckart, however, has pointed out to me that a very large proportion of the 

 soils of the Hawaiian Islands is acid ; and hence they are not in a condition 

 suited for nitrate formation without some previous treatment. 



British. Guiana Soils. The soils of this Colony have been critically 

 examined by Harrison 8 . He distinguishes eight types of soil, of which only 

 three occur within the part where the cane is cultivated. These three are : 



1 . The clay soils of the alluvial coast lands. 



2. The sand reef soils of the alluvial coast lands. 



3. The peaty or ' pegass' soils of the alluvial coast lands. 



Of these soils he writes : 



"Experience has indicated to us that in Class I. we find soils of marked 

 fertility : soils which, with careful cultivation and tillage, should not alone retain 

 their fertility for long periods, but give gradually increasing leturns. These are 

 the sugar cane and rice lands of the colony. 



* These averages have been given me through the courtesy of Mr. C. F. Eckart. 



48 



