1917] SOILS FERTTLIZEES. 515 



The soils are of residual, sedimentary, and alluvial origin. Including clay 

 pits and tidal marsh, 26 soil types of 19 series are mapped, of which the 

 Chester and Manor loams cover 23.9 and 22.8 per cent of the area, respectively. 



A study of the principal plantation soil types as found on the Island of 

 Hawaii, P. S. Bukgess {Hawaii. Sugar- Planters' Sta., Agr. and Chem. Bui. 

 45 (1911), pp. 100, pi. 1, figs. S). — This bulletin discusses the mineralogy, chem- 

 istry, physics, and biology of soils in general and deals with those of the Island 

 of Hawaii in particular. The soils of the island are classed physically as high 

 humus clay and silty clay loams. Colloidal aluminum and iron hydroxids are 

 said to give the soils their apparent clayey character. 



" The hygroscopic coefficients vary from 9 to over 26 per cent when deter- 

 mined by Hilgard's standard method, while the optimum moisture capacity 

 averages about 45 per cent of the dry weight of the soils. The ' free water ' 

 varies from 15 to 38 per cent, while the maximum moisture-holding capacity 

 is in all cases well above that for average mainland soils. These soils do 

 not usually cake badly unless thoroughly puddled. When worked under opti- 

 mum conditions they are fluffy and show good tilth. . . , 



" The soils, with but few exceptions, are high in total nitrogen, but its 

 availability is universally low. The same is more or less true of phosphoric 

 acid. Potash, both total and available, is high in all of the soils examined 

 except in those of the Hilo district. . . . The amounts of total and avail- 

 able soil potash follow with surprising regularity the amounts of total potash 

 as determined in the final molasses and in the molasses ashes from the mills 

 of the several plantations. The total lime figures vary from over 5 per cent 

 in the alkaline Kau soils to less than 0.2 per cent in acid Hamakua. . . . 



" The lime requirements for the surface soils vary from 1 ton of calcium 

 carbonate to 11 tons, depending on location. . . . The amounts of alkali salts 

 (the chlorids, carbonates, and sulphates of sodium) are in all cases negligible. 

 All of the surface soils are fair ammonifiers." 



Six series of nitrification experiments are also reported. " In the first, the 

 soils receivetl no additions of nitrogen but were incubated under standard con- 

 ditions of moisture and temperature to ascertain the nitrifiability of their own 

 organic nitrogen. In the second, ammonium sulphate was added ; in the third, 

 dried blood ; in the fourth, dried blood plus sufficient calcium carbonate to 

 exactly neutralize acidity ; in the fifth, dried blood plus gj'psum ; and in the 

 sixth, dried blood plus reverted phosphate." 



It was found that " considering the large quantities of total nitrogen which 

 these soils contain, the absolute amounts and the percentages of it nitrified are 

 very low. Ammonium sulphate nitrogen is nitrified approximately twice as fast 

 as dried blood nitrogen. As an average for the soils of the entire island, the 

 addition of lime doubles the nitrification of dried blood. In some instances it 

 multiplies it by three and four. Gypsum has practically no effect upon nitrifica- 

 tion in these soils. In some instances a loss is recorded. Reverted phosphate 

 increases nitrification by aproximately 35 per cent. 



" Nitrogen fixation as determined both by solution and by soil culture methods 

 is fair in Hawaii soils. Azotobacter forms are well distributed. Three dif- 

 ferent species (A. chroococcum, A. vinelandii, and A. vinelandii, n. sp. ?) were 

 isolated in pure cultures and tested for nitrogen fixation in both solutions and 

 soils." 



A discussion of the analytical methods used in this work is appended. 



Method of botanical soil investigations on the Voronezh Zemstvo Experi- 

 mental Field, S. K. Chaianov and S. S. Mushchenko (Metodika Pochvenno- 

 Botanicheskikh Izsliedovanii na Voroneshskom Opytnom Pol(b Gubernskago 

 Zemstva. [Yoronczhl: Yoronezh Prov., 1915, pp. V-\-17). — The method used con- 



