SOILS FERTILIZEBS. 31 



[Reclaiming' land injured by volcanic ash], C. C. Georgeson (Alaska Stas. 

 Rpt. 1913, pp. 21, 22). — Land at the Kodiak Station covered with volcanic ash 

 from the eruption of Katmai in 1912 was brought under successful cultivation 

 again by deep plowing to mix the underlying soil with the ash, the application 

 of fertilizers supplying especially nitrogen, which was lacking in the ash, and 

 the use of organic manures to supply humus. 



The improvement of marsh soils, A. R. Whitson, W. W. WfeiE, and H. W. 

 Ullsperger (Wisconsin Sta. Bui. 205, 2. ed. (1914), PP- ^8, figs. 12). — ^A second 

 edition of tbe bulletin previously noted (E. S. R., 25, p. 20). 



The effect of different fertilizers on the chemical and physical properties 

 of soil, A. Mausberg (Illus. Lamlw. Ztg., 34 (1914), No. 55, pp. 521-^23) .—The 

 substance of this article was contained in a previous report (E. S. R., 30, 

 p. 219). 



The maintenance of fertility. — Liming the land, C. E. Thorne (Ohio Sta. 

 Bui. 279 (1914), PP- 22). — Tbis bulletin i-eports later results of experiments on 

 the use of lime in a 5-year rotation of corn, oats, wheat, clover, and timothy 

 described in an earlier bulletin of the .station (E. S. R., 16, p. 1061). 



The experiments were made on a light, silty clay which had previously been 

 subjected to an exhaustive system of farming. Quicklime which had been used 

 (at the rate of 1 ton per acre) in the earlier experiments was subsequently 

 replaced by moderate applications (1 to 2 tons per acre) of ground limestone. 

 The lime was applied to the corn, and various combinations of fertilizers were 

 applied to the cereals, but not to the clover and timothy. 



The results show that liming has added materially to the yield of corn under 

 every treatment and on the untreated land. The lowest gain from liming was 

 obtained on the plat receiving phosphorus in basic slag, and the highest gains 

 were on the plats receiving nitrogen in oil meal, dried blood, and ammonium 

 sulphate. Without lime these carriers of nitrogen produced less total corn than 

 did sodium nitrate, but with lime they surpassed the nitrate in increasing the 

 yield. .Wherever sodium nitrate was used it increased the total yield and 

 reduced the demand for lime, but in no amount applied did it entirely obviate 

 the necessity for liming. 



With oats the results of liming were much less pronounced than with corn. 

 The greatest increase from liming was found on the plat receiving nitrogen in 

 ammonium sulphate. On several of the high nitrogen plats there was an 

 actual decrease in yield after liming. 



The wheat crop responded in all cases to lime except on the plat receiving 

 phosphorus in basic slag. The largest increase from liming was on the plat 

 receiving nitrogen in ammonium sulphate. 



Clover made a greater response to liming than any other crop. The bene- 

 ficial effect of sodium nitrate as contrasted with the other nitrogen carriers 

 used was more marked with clover than with any of the other crops. It is 

 suggested that a part of the superior effect of this material with clover, as 

 with corn, on the acid soil used in these experiments was due to the sodium, 

 but that " neither nitrate of soda nor bone meal nor basic slag nor any practi- 

 cable combination of these materials will furnish sufficient alkali to neutralize 

 this acid soil, unless used in such quantity that the cost will be prohibitive." 



The total gain in yield of the timothy crop due to liming was greater, and 

 the percentage gain nearly as great, as in the case of clover, and was much 

 greater than with the oats or wheat. As with clover, the timothy crop did not 

 respond on unlimed soil to applications of organic and ammonia nitrogen, but 

 showed a somewhat greater response than clover to these carriers of nitrogen 

 when lime was added. 



