SOILS — PBKTILIZERS. 327 



periments reported, the purpose being to show that fertilizers, Including stable 

 and green manures and artificial manures, serve as sources of nourisliment to 

 soil bacteria and thereby exert a favorable influence on their activities in mak- 

 ing available to plants the stores of residual and natural plant food in soils. 



The conditions of complete action of fertilizers, Becker (Fiihling's Landw. 

 Ztg., 64 (1915), No. 9-10, pp. 255-261). — A brief statement enumerating the 

 most important factors influencing the complete utilization of fertilizers in 

 soils by crops, such as moisture, humus, lime, tilth, adaptation to season, etc., 

 is given. 



Row fertilizing, Tacke (Mitt. Deut. Landw. Gesell., SO (1915), No. 9, pp. 

 118, 119). — Row fertilizing of oats and rye on sandy upland moor soils was 

 accompanied by an increase in crop yield in two consecutive years as com- 

 pared with broadcast application of fertilizers. 



Providing Germany with plant food, B. Rassow (Ztschr. Angew. Chem., 28 

 (1915), No. S2, Aufsatzteil, pp. 196-201).— This is a brief review of the fer- 

 tilizer situation in Germany. 



Vegetation experiments with different nitrogen and phosphoric acid fer- 

 tilizers, B. ScHULZE {Illus. Landiv. Ztg., 34 (1914), No. 00, pp. 817, 818, figs. 

 4). — In pot culture experiments with oats and mustard on a soil deficient in 

 nitrogen it was found that of three nitrogenous fertilizers tested the so-called 

 nitrate-diphosphate, consisting of apatite semidigested with nitric acid, gave 

 the best results, while little difference was observed between sodium nitrate 

 and calcium nitrate containing an excess of lime. On the basis of these re- 

 sults the nitrate-diphosphate is considered to be a valuable nitrogenous 

 fertilizer. 



Further tests on the same soil with the same crops using three other nitro- 

 genous fertilizers showed that a mixture of lime nitrogen and raw iron oxid 

 2 : 1 gave better results than pure lime nitrogen or lime nitrogen and Thomas 

 slag 1 : 2. Mixing the lime nitrogen with Thomas slag seemed to decrease the 

 availability of the nitrogen. 



In experiments with the same crops on a soil deficient- in phosphoric acid, 

 it was found that precipitated superphosphate, containing 30.37 per cent citrate- 

 soluble phosphoric acid, gave the best results, followed in order by super- 

 phosphate, Thomas slag and lime nitrogen mixture 2 : 1, pure Thomas slag, 

 and nitrate-diphosphate. 



The nitrogen of processed fertilizers, E. C. Lathkop (Chem. Netcs, III 

 (1915), Nos. 2887, pp. 145-14^; 2888, pp. 162-164; 2889, pp. 169-172; 2890, pp. 

 186, 187).— The substance of this article has been noted (E. S. R., 32, p. 217). 



How can crops be grown without potash manures next year? E. J. Ritsseix 

 (Jour. Bd. Agr. [London], 22 (1915), No. 5, pp. 393-406).— It is stated that 

 the lack of potash may be met by the use of wood ashes, damaged straw, 

 mangold and other leaves, and liquid manure. " These contain consid- 

 erable quantities of potash which, in the aggregate, would help materially in 

 coping with the present shortage. Moreover, the plowing up of leys and grass 

 land leads to the liberation of the potash stored up in the roots, stems, and 

 leaves, causing it to become available for the next crop." Two agencies sug- 

 gested for increasing the availability of potash in the soil are (1) sodium salts, 

 especially common salt and sodium sulphate, and (2) lime or chalk. "The 

 former can be used for mangolds and for cereals when necessary. Lime and 

 chalk are more suitable for leguminous crops, clover, etc." 



Possible sources of potash, G. G. Ceesswell (Jour. Soc. Chem. Indus., 34 

 (1915), No. 8, pp. 387-393) .—ThG author discusses chemical and other methods 

 for obtaining potash from sea water, seaweed, ashes, saltpeter, potash lakes 



