SOILS FEHTIIJZERS. 1021 



In the second series of experiments tlie etKciency of tlie slajr as ])urc-linse(l, of 

 tbe tine iiortion luissini; a siev«' havin.u nieslies 0.17 nnn. in diameter, of tlie 

 coarse portion wliic-li did not pass tlie sieve. ;ind of the insolnble residne left 

 after treatment aeeordins? to the AVaguer method was compared ou loam and 

 sandy soils. 



The etiiciency of the slags varied widely when applied on the basis of eqnal 

 amounts of total phosphoric acid, but these differences were greatly reduced 

 when equal amounts of citric-acid soluble phosphoric acid were applied. 

 White mustard utilized the less soluble slags to a greater extent thjin oats, 

 but in lioth cases the tineness of the slag was the most important factor in 

 determining the utilization of the phosphoric acid. 



In the case of oats, and to a less extent with mustard, the degree of tineness 

 greatly intluenced the etticiency, especially on loam soils. The insoluble residue 

 from the treatment with Wagner's reagent was much more effective than the 

 coarse portion of the slag in case of some slags, but almost without effect in 

 others. In sandy soils the fineness of the slag was of much less importance 

 than in clay soils and the insoluble portion was more effective. The addition 

 of bicalcinm phosjihate increased the coefficient of utilization of the insolnble 

 residne of the slag. The results indicate that the citric-acid soluble part of the 

 coarse portion is less efficient than that of the fine portion and thus that all 

 the phosphoric acid dissolved by the citric acid is not directly absorbable by 

 plants. 



Recent observations on leucite and its application as a fertilizer, U. Alvisi 

 and D. Venditori (Gaz. Chim. Ital., 37 {1U07), II, Xo. .'/. itj). 379-383; abs. in 

 C'hein. ZentbL, 1908, I, No. 3, p. 286). — The mineralogical chai-acter of leucite 

 is explained and its applications, especially its use as a fertilizer in Italy, are 

 referred to. Experiments to determine whether the potash of leucite or leucitite 

 would be renderetl more available by treatment with sujierphospliate in solution 

 or with orthophosphoric acid gave negative results. The authors conclude that 

 sulphuric acid as well as carbon dioxid and water often plays an important role 

 in the kaolinization of these substances. 



The use of feldspathic rocks as fertilizers, A. S. Cushman {Chem. News, 

 96 (1907), Xo.s. ^.JOO, 1)1). 205-207; 2501. pp. 218, 219; 2502, pp. 226-230; 2503, 

 pp. 238-2-'i0). — Reprinted from Bulletin 104 of the Bureau of Plant Industry of 

 this Department (E. S. K.. in. p. 322). 



On the influence of solubility on availability, G. Daikuhara (Bui. Imp. 

 Vent. Afjr. Expt. Stii. Japan, 1 (1907.), No. 2, pp. 87-91).— Fvom the results of 

 experiments with barley the author concludes " that in the presence of lime as 

 carbonate, the necessary amount of magnesia applied in the form of crystallized 

 sulphate for Parley in sand culture is so small that the best ratio of lime to 

 magnesia becomes 60: 1, while in the form of nitrates of calcium and magnesium 

 in water culture the best ratio for (Jramineie is between 1 : 1 and 2 : 1. This con- 

 clusion will hold good also for various sandy soils, while for clayey soils the 

 best ratio . . . will differ. The calculation from the above n-snlts shows that 

 with barley 4.0 parts ML■S()^.7HJ() are agronomicaliy e(piivaleiit to 100 parts 

 niagnesite, while with rice this e<|uivnleiit is still liiglicr, viz.. O.S." 



On the most favorable ratio of lime to magnesia for the mulberry tree, 

 M. Nakamura (Bui. Imp. Cent. Agr. Erpt. Sta. Japan, I (1907), Xo. 2, pp. 

 129-133, pi. 1). — From the results of jiot experiments here reported the conclu- 

 sion is drawn that for the mulberry tree the best ratio of lime to magnesia 

 is o : 1. 



On manuring with magnesium sulphate, G. Daikuiiaka (Bui. Imp. Cent. 

 Ayr. Expt. tsta. Japan, 1 (1907), No. 2, pp. 81-86, pi. l).—Vot experiments with 



