74 CHAPTER V 



B. CLIMATE CLASSIFICATION. 



1. Upland soils : -Soils formed under lower temperature and greater rainfall, 

 and distinguished by a large content of organic matter and nitrogen, and by a 

 low content of elements of plant food in an available state ; these elements 

 having been removed by rainfall. 



2. Lowland soils : Soils formed under a higher, temperature and less rainfall,, 

 and characterized by a lower content of organic matter and nitrogen, and by a 

 higher content of the elements of plant food in a state of immediate availa- 

 bility ; which is due in part to the receipt of some soluble constituents from 

 the upper lands, and to a smaller rainfall over the lower levels. 



It is on the dark -red soils and on the sedimentary soils that the high 

 returns of cane have been grown. The sedimentary soils are often of great 

 depth, and sometimes extend down as far as thirty feet. 



The colour of the yellow soils is due to ferrous iron, and it is to the presence 

 of this body that Maxwell attributes the smaller productivity of this type. 



Peculiar perhaps to the soils of this locality is the not infrequent presence 

 of large quantities of manganese and titanium. Kelly 8 has reported 

 analyses wherein the former, calculated as Mn 3 O 4 , amounted to 9 per cent.,, 

 the latter, in some cases, reaching 35 per cent, calculated as TiO 2 . 



COMPOSITION OF HAWAIIAN SOILS (MAXWELL). 



a. Official (U.S.) method, b. Complete analysis on water-free soil. 



Usually the red soils are light, and easily worked, and drain with great 

 facility ; though clay-like when wet, they do not become compacted on 

 drying, and may be tilled under conditions of rainfall impossible with true 

 clays. The apparent specific gravity is very low, and Burgess estimates 

 this as i -i, giving the weight of an acre-foot as only 3,000,000 Ibs. The 

 pore space in these soils is thus exceptionally high, a factor which leads to 

 opportunity for rapid drainage, aeration, and large root development. 

 This physical condition is probably as large a factor in the production of 

 large crops as is the chemical composition. 



The typical analyses of various types of Hawaiian soils given here are 

 due to Maxwell. 



The mean composition of the soils of the different islands, based on the 

 result of 397 analyses by the Official (U.S.) method, is as below ; 



