118 EXPEEIMENT STATION BECOED. 



The 3-ellow soils occupy the central part of Cuba to the east of Havana. 

 They differ from the light gray soils in their higher content of clay and fewer 

 rock fragments. They have an average content of nitrogen of from 0.115 to 

 0.286 per cent ; phosphoric acid, 0.064 to 0.221 per cent ; potash, 0.037 to 0.182 

 per cent ; and lime, 0.127 to 0.892 i^er cent. 



The red soils occupy a considerable area in east central Cuba and are char- 

 acterized by their high clay content, being derived from weathered limestone 

 rich in iron, alumina, and silica, and by high lime and phosphoric acid coo- 

 tents. Tobacco is the principal crop. In the extreme eastern part of the region 

 there occur rather extensive areas of washed soils which differ from the typical 

 red soils in that they are less porous and more moist. Sugar cane'is the prin- 

 cipal crop grown thereon. The analyses of these soils showed for nitrogen 

 from 0.192 to 0.290 per cent; phosphoric acid, 0.010 to 0.706 per cent; potash, 

 0.072 to 0.514 per cent ; and lime, 0.278 to 15.040 per cent. 



The black soils occupy the ea.steru lowland region of Cuba, They are noted 

 for their high calcium carbonate and very high nitrogen contents. It is believed 

 that the dark color is due to the large amounts of plant debris from the sugar 

 cane. Analyses showed nitrogen, 0.045 to 0.422 per cent; phosphoric acid, 

 0.030 to 0.356 per cent; potash, 0.038 to 0.356 per cent; and lime, 1.038 to 

 53.329 per cent. 



The sandy soils of Ileri-adura and of the Isle of Pines are used for the produc- 

 tion of citrus fruits. They are stated to be poor in the mineral constituents of 

 plant food, analyses reported showing nitrogen, 0.076 to 0.104 per cent ; phos- 

 phoric acid, 0.011 to 0.021 per cent; potash, 0.004 to O?006 per cent; and lime, 

 0.002 to 0.031 per cent. 



The use of fertilizers is stated to be quite general on all the soil types. 



Incidentally, analyses of bat guano deposits of the mountain caves of western 

 Cuba are reported. These deposits, although being used as a fertilizer, are not 

 very extensive and are generally low in plant-food constituents. 



Soil investigations, W. P. Kelley (Hawaii Sta. lipt. 1911, pp. Ji3-51, figs. 

 2). — Brief reference is made to previous investigations on pineapple soils (E. 

 S. R., 24, p. 621) and an account is given of a further study of movement of 



water in different Hawaiian soils. These studies included measurements of the 



■» 



rate of capillary rise and percolation of water through columns of soil in glass 

 cylinders. 



The results show that capillary movement of water in the soils varies between 

 wide extremes. It was most rapid in the experiments here reported in humus 

 sandy soil and slowest in clay soil. Percolation was slowest through soils con- 

 taining the highest percentage of clay and fine silt. 



Brief reference is al.so made to a comparison of methods of determining the 

 so-called humus in soils (E. S. R., 27, p. 7) and to the beginning of work on :i 

 soil survey of the islands. 



The origin, composition, and properties of the manganiferous soils of 

 Oahu, W. P. Kelley (Ho/waii Sta. Bui. 26, pp. ^2--5G). — These soils, which 

 are located on the upland plateau between the Waianae and Koolau Mountain 

 ranges, at an elevation of from 650 to 900 ft., frequentlj'^ contain 5 per cent of 

 manganese oxid (MuaOi) and sometimes as much as from 9 tt> 10 per cent. 



A study of the chemical composition of the lava from which the soils are de- 

 rived and of the lava alteration products, as well as of the position in which the 

 soils occur, indicates " that the concentration of manganese has come about 

 through the action of solution and leaching, followed by subsequent oxidation 

 and deposition." The manganese has become soluble in the normal weathering 

 of the basaltic lavas and has been transported and redeposited from the solution. 



