►EL8 — FERTILIZERS, 



don], 88 | 1905 i, No. 515, II, p. 607 I. It is stated thai the principal sources of carbon 

 dioxid in the soil are micro-organisms and the roots of the higher plants. 



The results of studies by means of special apparatus of the rate of production of 

 carbon dioxid by micro-organisms and the roots of plants are reported and from 

 them it is estimated thai the organisms in l hectare of soil t.. a depth of 10 cm. 

 produce 75 k'_ r . of carbon dioxid per day during the 200 days a year on which the 

 temperature reaches a mean of L5° ( '. A-ssuming thai a hectare of Boil bears 2,000,000 

 plants ui' a cereal, the production of carbon dioxid bytheir roots would, according 

 to the results reported, be 60 kg. per hectare daily. Of the plant- experimented 

 with, red clover, beets, and <»ats produced the largesl amounts of carbon dioxid. 



It is claimed thai the large amounts of carbon dioxid derived from these sources 

 converl a notable amounl of Boil material into soluble forms. It is held thai the 

 Bolvenl action of roots, especially young roots, is due to this carbon dioxid and nol 

 to organic acids, which, as Czapeck and Kohn and Kossowich have shown E. 8. R., 

 16, pp. .'!44, L048), are nol secreted by plants. 



Contributions to our knowledge of the aeration of soils, K. II. K i \< . i Sci* na . 

 a. sir., 22 | 1905), No. 564, />/>. /'■>■'> $99). A review of Bulletin 25 of the Bureau ol 

 Soils (E. s. R., lti, p. 752), claiming thai a weakness of the conclusions drawn lies 



in the tact that they are based upon "the mathematical treat nl of a very limited 



series of laboratory experiments, which, however, have been executed with greal 

 care," but have not been checked l>y field observations and experiments. It i- 

 maintained "that rates of transpiration, as measured in the Laboratory trials, are 

 quite inapplicable for use in giving a measure of the rate of How of air through Boils 

 under field conditions." 



The influence of packing of the soil on the growth of oats, C. vox See] bobs'] 

 and Kkzvmowski {Jour. Landw., 53 [1905), No. 3, pp. 969 278). -The observations 

 recorded indicate that rolling hinders the growth of plants by interfering with trans 

 formation of nitrogen in the soil and with root breathing. The influence of rolling 

 on the lodging of cereals is discussed. 



Bare fallow, C. von Seelhorst t Deut. Landw. Presse, 32 \ 1905), Not. ,'/. />/>. 601, 

 602; 72, pp. 608 610; 73, pp. 615, 616). -A review of evidence showing, as Pfeiffer 

 claims (E. S. R., L6, p. 858), that hare fallowing is soil robbery and is as a rule had 

 practice on ordinary soils I nol containing an excess of organic matter 



Investigations on evaporation from cultivated soils and from uncultivated 

 stubble soil, C. vox Seelhorst (Jour. Landw., 53 (1905), No. 3, pp. ?64r-268). 

 Observations on large vegetation cylinders are reported which indicate thai incase 

 of heavy rainfalls more water evaporates from hoed soil than from unhoed, bu1 thai 

 with small rainfalls the reverse is true. 



Investigations on the percolation of rain water in sandy and loamy soils, 

 C. vox Seelhorst (Jour. Landw., 53 (1905), No. 3, pp. 960-263). Observations on 



vegetation cylinders of l.l cubic meter' content showed no greal difference in the 

 amount of evaporation on sand ami medium loam soil whether fallow or stnhhle. 



Some agricultural and geobotanical observations, S. Ki;\\ k<>\ Zend. Qhaz., 

 1904, No8. ?;, ;;,• "/'■-■. in Zhur. Opuitn. Agron. i Russ. Jour. Expt. Landw.), 6 | 19 

 No. /./'/'• ■'/' ?6). — One of the observations relates to the water-eoluble salts in the 

 soil. The concentration of the soil solution- w a- found to vary greatly according to 

 the weather, the properties of the soil, the relief of the locality, and other conditions. 

 It was noted that a field apparently uniformly cultivated and with a uniform cover 



of living plants and plant remains -lowed very different am.. nuts of substances solu- 

 ble in water at points close to one another. Such fluctuations the author ascribes 

 to difference- in thickness of the plant cover, to the inline;, e of animal-, etc. 



Daring the winter the soil solution remained almost unaltered; in the spring there 

 was in the drained soil a washing out or accumulation «»f dissolved substances accord- 

 ing to the character of the weather until a sufficient plant covering grew up. when 



