426 EXPERIMENT STATION EECOED. 



The results showed not only orthoclase, sanidine, and microcline, but also 

 leucite to be very slightly available as sources of potash for plants. Biotite 

 and muscovite in finely ground condition were more available than minerals of 

 the feldspar group, although biotite was always more available than muscovite. 

 ^^■hen i)ure muscovite was replaced as a source of potash by mic;i schist contain- 

 ing muscovite, still better results were obtained. Eleolite as a pure mineral in 

 fine ground condition was very slightly assimilated. For this reason the author 

 thinks that the previous good results obtained with rocks containing iiephaline 

 were due not to uephaline but to the biotite which was present. 



Investig'ations on the chemical coniposition of the Plantegaarde salt 

 deposits, 1909, D. J. Hissink and G. B. Van Kampen (Verslag. Landhouwk. 

 Onderzoek. RijkslandJyouioproefstat. [Netherlands], 1911, No. 9, pp. 36-55). — 

 The results are reported of chemical analyses of samples of salt obtained by 

 borings near Winterswijk, Holland, in a search for potash deposits. The potash 

 content varied considerably, the highest amount being 14.8 iwr cent obtained 

 from a sample at a depth of about 8CK) meters. The author believes that 

 although these deix)sits are not as a rule rich in potash they may become of 

 economic iu)portance. 



The power of the neutral salts of potash to convert aluminum silicates 

 into soluble forms, A. A. Stol'gane (Izv. Moskov. Selsk. Khoz. Inst. (Ann. Inst.- 

 Agron. Moscou), 17 (1911), No. 2, pp. 359-363). — Various minerals containing 

 potash were treated with ammonium chlorid and barium chlorid solutions and 

 the potash extracted determined. 



It was found that muscovite and biotite yielded much more potash under this 

 treatment than orthoclase, sanidine, and leucite. This agrees closely with the 

 results of pot experiments. There was, howevei*, one exception, namely, uepha- 

 line (eleolite), which yielded considerable potash on treatment with neutral 

 solutions, although in pot exi>eriments the fertilizing effect of this material was 

 vei"y small. 



Fertility experiments in a rotation of cowpeas and wheat, — I, The utiliza- 

 tion of various phosphates, C. A. Mooers (Tennessee 8ta. Bui. 90, pp. 57-90, 

 figs. 3). — This bulletin gives the results of comparative tests of acid phosphate, 

 finely ground rock phosphate, bone "meal, and Thomas slag on a cowpea-wheat 

 rotation at the station and on 3 other Tennessee farms, with analyses of the 

 soils of the farms and of the phosphates used. All of the soils were poor in 

 lime and all except one were poor in phosphoric acid. In each series of experi- 

 ments one-half of each plat was limed and the other half was left unlimed. 



The first series of experiments, which covered 4 years, was conducted at the 

 experiment station on a Cumberland loam which was deficient in lime but 

 otherwise well supplied with plant food. The second series, also extending over 

 4 years, was made in Knox County on a reddish yellow silt loam which was 

 somewhat deficient in lime and other plant food. The third series, lasting 

 3 years, was made in Warren County on a typical gray colored silt foam 

 known to be vei-y poorly supplied with both phosphoric acid and lime and, as 

 a rule, also with nitrogen. A fourth series of experiments, covering only 2 

 years, was made in White County on a typical dark red soil derived from lime- 

 stone but known to be naturally deficient in phosphoric acid. The results 

 obtained with wheat in the first 3 series of experiments are summarized in 

 the table following. 



