13 



Kellner 1 made some observations on the action of lime 

 manure on paddy fields. Complete infertility had resulted in 

 several places. He attributed part of this to loss by leaching. 

 Among other things the action of phosphates in two soils was in- 

 vestigated. He mixed in from 0.25 percent to 5 per cent of 

 quicklime, and after two weeks added a solution of potassium tri- 

 hydrogen phosphate. Lime apparently caused an increase in the 

 soluble phosphoric acid. The maximum effect was obtained with 

 i per cent to 2.5 lime. After two months still more phosphoric 

 acid had become soluble. 



Gerlach 2 repeated Thompson's work 3 on the absorption of 

 phosphoric acid by soils. The results here recorded show that 

 clay, peat, and sand which have been extracted with hydrochloric 

 acid have no power of absorbing free phosphoric acid, sodium 

 phosphate, and superphosphate. Calcium and magnesium car- 

 bonates absorb phosphoric acid, while iron and aluminum oxides 

 do so very completely. In the first case the compounds formed 

 are comparatively soluble and are completely extracted by water 

 charged with carbon dioxide. The compounds formed with iron 

 and aluminum are insoluble in water even in the presence of car- 

 bon dioxide, but are more or less dissolved by the prolonged 

 action of organic acids. He endeavored to determine the form 

 in which phosphoric acid is absorbed. A solution of mono-cal- 

 cium phosphate was placed in contact with calcium carbonate. 

 Di- and tri-calcium phosphates were formed depending on the 

 relative amounts of the materials used. When iron and aluminum 

 hydroxides were the absorbents, not only was the phosphoric acid 

 absorbed, but the calcium was also retained. Di-calcium phos- 

 phate and an iron phosphate were formed. The author concluded 

 that normal ferric phosphate is formed when sufficient ferric 

 hydroxide is present. A basic phosphate of iron was also con- 

 sidered a possibility. 



Stocklasa 4 estimated the yearly loss of calcium carbonate 

 from various soils. The results are of interest as bearing on the 



1 Bull. Coll. Agr. Tokyo Imp. Univ., 1891, 9, i. 



2 I^andw. Versuchs-Stat., 1895, 46, 201. 



3 Iiiaug. Dissertation, Dorpat., 1890. 



4 Bied. Centr., 1895, 82. 



