722 EXPERIMENT STATION RECORD. 



nitric acid, but was not completely removed. Some of the potash dissolved 

 by fifth-normal nitric acid was removed from solntlon by fixation in the soil, 

 but the percentage of fixation was in no case large. 



Orthoclase, mica, and nepheline as sources of potassium for plants, D. N. 

 Pbianishnikov (A&s. in Jour. Soc. diem. Indus., 28 {1909), No. 13, p. 122).— 

 In this abstract of a pai)er iiresented at the International Congress of Applied 

 Chemistry at London it is stated that plants can assimilate very little potash 

 from orthoclase and mieroeline even when finely powdered, but that mica, and 

 to a still greater extent, nepheline are valuable sources of potash, about 17 per 

 cent of the potash of the mica and 25 per cent of that of the nepheline rock 

 being assimilated by plants. 



Influence of calcium carbonate and ammonium sulphate on the assimila- 

 tion of phosphoric acid [by plants] from different sources, D. N. Prianish- 

 NiKOV {Ahs. in Jour. Soc. Chem. Indus., 28 {1909), No. 13, p. 722). — An abstract 

 is given of a paper presented at the International Congress of Applied Chem- 

 istry at London in which investigations were reported tending to show that 

 the addition of calcium carbonate iiroduced a marked decrease in yield when 

 applied with bone meal, raw phosphate, and pure tricalcium phosphate on 

 sandy soils in connection with calcium nitrate or other nitrates, and no in- 

 crease when used with basic slag, acid phosphate, and dicalcium phosphate. 



Different results were, however, obtained when the nitrate was replaced by 

 ammonium sulphate, which decomposes phosphates, the most marked effect 

 being produced when half of the nitrate was replaced by the sulphate. When 

 ammonium sulphate was used alone the plants were injured by the physiological 

 action of the acid condition produced in the soil, although they were super- 

 saturated with phosphoric acid. The injury from this cause was reduced by 

 the application of a small quantity (0.25 per cent) of calcium carbonate and 

 the yield was increased. When the amount of calcium carbonate was increased 

 to more than 1 per cent all of the free sulphuric acid was neutralized and the 

 plants suffered from phosphoric acid starvation. The effect of the different 

 methods of treatment was apparent not only in the yield of crops but also in 

 their content of phosphoric acid. See also a previous note (E. S. R., 21, p. 24). 



Fertilizer experiments with increasing* amounts of Thomas slag*, A. Imel- 

 MANN {Dent. Landn: Presse, 35 {190S), No. 63, pp. 667, 668, figs. 3; ahs. in 

 Zentbl. Agr. Chcni., 38 {1909), No. 5, p. 356). — In the experiments reported 

 Thomas slag was used in' amounts of 400, 600. 700, and 800 kg. per hectare 

 (from 356 lbs. to 712 lbs. per acre) on rye and oats in connection with a basal 

 ration furnishing potash and nitrogen. 



The yield, the profit, and the after effect increased with the increase in the 

 application of slag. The results of the experiments indicate in general that slag 

 is the cheapest form of phosphoric acid for light sandy soil. 



Phase relationships of the calcium phosphates and bearing upon certain 

 agricultural and biological problems, H. Bassett, Jr. {Ahs. in Chem. Ztg., 33 

 {1909), No. 69, p. 626; Jour. Soc. Chem. Indus., 28 {1909). No. 13, p. 7;22).— This 

 is a note on a paper read at the International Congress of Applied Chemistry at 

 London, reporting investigations which the author has been carrying on for 

 some time on the three-component system. CaO — P.Or> — H2O. and which has 

 enabled him to scale a solid model of the region of orthophosphates. 



The results of the investigation throw light on the conditions under which 

 various mineral phosphates have been formed and on the nature of the naturally- 

 occurring so-called tricalcium phosphates, as well as on the condition in which 

 phosphoric acid is present in the soil. It is stated that if is probable that the 

 available phosphoric acid of the soil is in large part in the form of tetracalcium 

 phosphate. The same is true of the phosphorus of Thomas slag, and this fact 



