WATER SOILS. 533 



])Imt(') ami iiitrni^'cn salts (nitrate of soda and sulphate nf aininonia). In case <if the 

 oats and of the <>:rass and alfalfa mixture applieations of gypsum furnishin<;- more 

 than 1 gm. of lime (CaO) per pot caused a decided reduction of yield. With larger 

 applications the reduction in yield was im)portional to the amount of the ajiplication. 

 Potatoes were not thus affected by applications of gypsum. In case of this crop the 

 effect of gypsum and of calcium carbonate was the same. Tiie injurious effect of the 

 gypsum was overcome by applying calcium or magnesium carbonate in connection 

 with it. The effect of the gypsum was also reduced to a minimum by admixture of 

 the loam soil with the sand, thus indicating that in general practice where gypsum 

 is used in small amounts on ordinary soils the injurious effect would not be observed. 

 Only when applied in small amounts did the magnesium carl)onate increase the yield 

 of the grass-alfalfa mixture. With larger applications of this material there was a 

 reduction in yield. Horse beans and vetches were not thus affected by the larger 

 applications of magnesia. The magnesium carbonate was apparently cai)able of 

 almost completely replacing lime. The highest yields, however, were obtained when 

 the carbonates of lime and magnesia were used together. It was also observed that 

 even when lime had been applied in excess the magnesia was still capable of pro- 

 ducing a considerable increase in yield. This is of great i)ractical importance as 

 indicating that dolomitie marl is of at least equal value with calcareous marl. 



The plant food capital of the soils of western Germany, with especial ref- 

 erence to their geological nature, taxable value, and fertilizer requirements, 

 F. WoHLTMANN {Das Ndlirt^toff- Kapital west-deutscJier Boden, mit hcmnderer BeriXck- 

 sichtigung Hirer geologischen Natur, Hirer Katasterbonitdt und Hires DungebediXrfnisses. 

 Bonn: Carl Georgi, 1901, pp. 63, figs. 3. Ber. Inst. Bodenlehre «. Pflunzeribau Landw. 

 Ahtd. Bonn-Poppelsdorf, 1901, No. 1). — This is a memorial prepared on the occasion 

 of the dedication of the new institute for soil study and plant culture of the agricul- 

 tural academy of Bonn-Poppelsdorf during the summer of 1901, and summarizes 

 jtrevious work on soils at this institution, giving in addition a brief description of 

 the l)uilding and equipment of the new institute and a list of publications of the 

 author from 1894 to April 1, 1901. A general discussion is given of the geological 

 and niineralogical character of soils, their mechanical composition and physical prop- 

 erties, their chemical composition and plant food capital, their absorptive power 

 with reference to salts and gases, the kind and amount of bacteria present, and the 

 relation of soils to climatic conditions. The methods used in the soil analyses 

 reported are described in detail ' and the results of mechanical and chemical exam- 

 inations of 66 samples of typical soils taken to a depth of 1 meter arie reported and 

 discussed. In most cases analyses were made of each soil at 4 different dejiths, to 25 

 cm., 25 to 50 cm., 50 to 75 cm., and 75 to 100 cm. The results show wide variation in 

 the comi)Osition of the same soil at different depths, this variation frequently being 

 greater than that observed between different soils, as is shown in the following 

 table: 



Variations in the composition of soils of Western Germanij. 



Variations in 



different 



soils. 



l^cv cent. 



Nitrogen 0.055- 0.498. 



Calciiim oxid Trace-22. 06'' 



Maf,nicsium o.xid 0. 019- 0. 659 



I'll. .si-horic acid .018- .2.% 



Potiish dissolved by trcalinent with cold acid . 02(>- . 212 



Potash dissolved by treatment with hot acid i .056- .•'>04 



Variations in 



the. same soil 



at different 



depths. 



Per cent. 



0. 007- 0. 498 

 Trace-35. GOO 



0.011- 8.610 

 .060- .305 

 .019- .188 

 . 0.56- 1. 133 



'The methods here described are a revision of those given in Jour. Landw., 44 

 (1896), No. :,, i)p. 211-2:54 (K. S. K., 8, p. 573). 



