SOILS — FERTILIZERS. 621 



granite, niiea-scbists, and feklspjithic rocks aro well supplied with potash, some 

 of those derived from grauulite and schists are insutHciently supplied with this 

 constituent. The soils are as a rule benefited by potash fertilizers, and the 

 systematic use of such fertilizers is considered an essential factor in agricul- 

 tural progress in the region. 



The pakihi soils of Westland, B. C. Aston (Jour. New Zeal. Dci,t. Agr., 

 1 (WW), No. 1, pp. 22-27, fif/x. 3). — These soils, which occur in large areas in 

 Westland, New Zealand, consist as a rule of retentive and compact surface soils 

 overlying sand and a bowlder or cement bottom. Iron hardpan is frequently 

 present. The soils are wet and acid and covered with swamp plants. 



Analyses of several samples of the soils indicate that they are very deficient 

 in available phosphoric acid and potash, as well as in lime and magnesia. The 

 total nitrogen, however, is high. Pot experiments with the soils indicated that 

 they were especially in need of lime. Drainage and liming with the use of phos- 

 phatie and potash fertilizers is therefore recommended as the best means of 

 improving these soils. 



The formation and decomposition of humus in cultivated soils, B. Heinze 

 {Laiidw. Mitt. Prov. Sachscn. u. Nachbaistaat. Halle, 1009, pp. I.'f5-l.'i6; ahs. in 

 CentU. Bakt. [cfc], 2. AM., 26 {1910), No. 25, pp. 682, 683).— It is stated that 

 when the necessary organic matter is present in the soil, fungi, bacteria, algse, 

 lichens, and mosses all cooperate in changing it into humus. 



The formation of the humus is more or less independent of the air, as certain 

 anaerobic bacteria decompose organic matter, causing a kiss of hydrogen and 

 oxygen and a concentration of carbon and thu.> producing the dark brown color 

 characteristic of humus. Certain hyphal fungi, as CUtdothrlv odorifcra, Strepto- 

 thrix chromogena, and Trichoderma aid in the decomposition of the organic 

 matter, even when the soil has an acid reaction. 



After the humus is formed, other b'acteria, such as Azotobacter, commence 

 to decompose it. The addition of stable manure aids materially, as it seems 

 to contain, or act as a carrier for, many of the humus-fermenting bacteria, the 

 humus acting as a source of carbon to the bacteria, especially the nitrifying 

 species. 



The biolog'ical absorption of methan and the distribution of methan organ- 

 isms, I. GiGLioLi and G. Masoni {^taz. »S'/k/-. Agr. ItaL, J,2 {1909), No. 9, pp. 

 589-608; abs. in Rev. G6n. CMm., 13 {1910), No. 3, p. 18; Chem. ZentU., 1910, 

 I, No. Jf, p. 294). — In experiments on the absorption of methan in the presence 

 of oxygen by the methan bacteria of Kaserer and of Sohngen. light was found 

 to exercise no special influence, but a high temperature was found to be favor- 

 able, the optimum being about 30° C, although many of the bacteria were active 

 at other temperatures. These micro-organisms are less numerous in the upper 

 layers of the soil than in the deeper j)ortions. They were also found in the bed 

 of streams, in sewer deposits, and in stable manure. 



By the absorption and partial transformation of the methan into fixed organic 

 material, these micro-organisms are constantly adding to the fertility of the 

 soil. 



Experiments on ammonia and nitrate formation in soils, J, G. Lipman and 

 P. E. Brown {Centbl. Bakt. [etc.], 2. Abt., 26 {1910), No. 20-2>,, pp. 590-632).— 

 The authors give the results of ii large number of exiieriments on ammonifica- 

 tion and nitrification in soils and culture solutions under various coiKlitions 

 and with different animal fertilizers, including a number »if facts bearing a nior" 

 general relation to these processes. 



Experiments were undertaken and data as to methods used and results ob- 

 tained are given on the following points: The bacteriological relations as 

 affected by the addition of dextrose uud sodium citrate to the soil ; ammonifica- 



