SOILS FERTILIZERS. 7l7 



The decomposition of the feldspars, A. S: Cushman and P. Hubbard (U. S. 

 Dciit. A;/!-., Office Pub. Roads Bui. 28, pi). 29, ftij.^. 6). — This bulletiu deals with 

 studies of uuH'hanical, physical, and chemical lactors which modify the decom- 

 position of feldspars, the results of which are thus summarized: 



"(1) Water acts immediately upon finely powdered feldspars, as can be 

 shown by an indicator, such as phenol phthalein. The reaction does not proceed 

 far, owin^ to the clogging of the unremoved decomposition products. 



"(2) The soluble alkaline^ bases set free by the decomposition are prevented 

 from passing into solution by absorption. 



"(3) The decomposition reactions can be made to go further by mechanical 

 abrasion in the presence of water, by treatment with dilute solutiims of certain 

 electrolytes and by electrolysis. 



"(4) The decomposition of ground feldspar can be hiade practically complete 

 in the laboratory by properly combining these modifjnng factors." 



The views regarding the mechanism of the decomposition reactitms presented 

 in previous publications (E. S. K., 17, pp. 301, 598) were confirmed in these later 

 investigations. 



It is stated that " the fundamental principles of the extraction of potash from 

 finely gromid feldspathic rocks by process of electrolysis, either with or without 

 the addition of an acid to the anode chamber, have been made the basis for an 

 application for a United States patent, so that the method may be used by the 

 Government of the United States or any of its officers or employees in the prose- 

 cution of work for the United States, or by any person in the United States 

 without the payment of royalty." 



Experira^ents to determine the available phosphoric acid in soils, O. 

 Hofma:^-Bang {K. Laitdtbr. Alad. llaiidl. och Tidskr., J/S (1006), No. S-J/, pp. 

 316-333). — Fertilizer trials with wheat, barley, beans, and mustard were made 

 by the author during 1902-1905, and the amounts of phosphoric acid contained 

 in the harvested crops compared with those extracted by different solvents 

 recommended in soil analysis, as follows : Hydrochloric acid, sp. gr. 1.12, 

 digestion for 3 hours on a water bath ; hydrochloric acid, sp. gr. 1.019, digestion 

 for 48 hours at room temperature ; 2 per cent acetic acid, 48 hours' digestion ; 

 2 per cent citric acid, digestion at room temperature for either 48 hours or 

 7 days. 



The soil experimented with was a calcareous soil, containing 0.2G9 per cent 

 total nitrogen. The following mineral components were extracted therefrom 

 by the first solvent given: KnO 0.33 per cent, P.Os 0.8 per cent, CaO 0.75 per 

 cent, MgO 0.54 per cent, F.Oa 3.22 per cent, ALO3 3.88 per cent, and SiO, 0.23 

 per cent. The results given go to show that for the soil experimented with, 

 and very likely for soils of similar compositicm, digestion with 2 per cent 

 acetic acid gives the most satisfactory indication of the content of phosphoric 

 acid in the soil that is immediately available for plant growth. — f. w. woll. 



Acid soils, A. L. Knisely {Orc</ijii Sla. BuL i)0, pp. 23). — This bulletin sum- 

 marizes the replies made by 80 farmers in different parts of Oregon to a cir- 

 cular of inquiry sent out by the station regarding the character of the soil of 

 their farms, the principal crops grown, the principal wild grasses and weeds, 

 and the reaction of the soil as determined by the litmus paper test. 



Of the SO tests of soil for acidity made and reported by farmers, 10 per 

 cent showed no acidity, 35 per cent very little acidity, 38.75 per cent considerable 

 acidity, and 10.25 per cent strongly acid. The majority of the extremely acid 

 soils examined in these tests were dai-k loam, muck, beaver dam or peat, 

 which usually are rather poorly drained. " In a few cases upland sandy, 

 gravelly clay loams have l)een found to be very acid. A majority of the 

 sandy and clay loams examined possess a considerable degree of acidity. 



