SOILS FERTILIZERS. 817 



tioally the same amount and to depths of 8 or 10 ft. If the movement is slow 

 ami the so.il conditions favorable to percolation, then in the soil near the head 

 ditch there is danger of loss by the percolation of the water far beyond the 

 reach of the root systems." 



The physical condition of the soil in relation to agriculture, T. Hallissy 

 {Irish Funning World, Jl (1908), Xo. 1081, p/>. ll^.i, //'/-}; Farmers' (inz., 67 

 (nW8), .Vo.s. .',7, pp. 1013, 101.',; .',S, p. /O.W).— This is a report of a lecture in 

 which the intluence of the various physical factors on the fertility of the soil 

 w.is discussed, but special emphasis was laid upon the relation of the soil to 

 water. 



While not minimizing the importance of the chemical and biological conditions 

 (if the soil, the author stated that " texture is what the farmer has always made 

 the basis for his diagnosis as to its value, and modern science confirms his 

 judgment." 



Investigations on the composition of the air of cultivated soils, E. Lau 

 {licitrai/i ;///• Kcnntnis Urr Zuaatnincnsctzuitg der i»i Ack( rbodeii bcfindlichen 

 Liift. Inaug. Diss. Rostock, 1906, pp. 34, pi. 1, fig. 1 ; rev. in Zentbl. Agr. Chem., 

 .il (1908), Xo. 7, pp. 433, 431/). — A series of investigations on the conditions 

 which infiuenc*e the composition of the soil air is reported, from which the 

 following conclusions are drawn : 



The soil air is richest in carbon dioxid in summer and poorest in winter, 

 the amount apparently varying with the temiierature and the conseiiuent in- 

 tensity of the decomposition of the organic matter and the formation of carbon 

 ilio.xid. The maximum. carbon dioxid content was noted in the months of July 

 and August, the minimum in February. The soil air is poorer in carbon dioxid 

 at 2 o'cUx-k at night than at 2 o'clock in the daj\ 



The air of ssindy soils contains the least carbon dioxid, that of moor soils 

 the most, the air of loam soils being intermediate in this respect. The carbon 

 iliu.vid content varies with the humus content as well as with the i)hysical 

 I>n>|>erties of the different soils. It is smallest at the surface and increases 

 with the depth, the differences in this respei-t being greatest in case of moor 

 soils and least in sandy soils. 



The oxygen content stands in definite relatiim to the content of carbon dioxid, 

 that is. the richer the soil air in carbon dioxid the poorer it is in oxygen, this 

 i»«'ing clearly due to the fact that the carbon dioxid results fx*om the oxidation 

 of humus. 



riant root respiration has a marked effect upon the carbon dioxid content of 

 the soil air. The air of soils bearing plants is decidedly richer in carbon 

 dioxid than that of bare soils, and the carbon dioxid content is greater in the 

 vicinity of the plant roots than below them. The carbon dioxid content in- 

 creases with the growth of the i»lants and with the rise of temperature. Soils 

 lK>jiring potatoes and lupines contain larger amounts of carbon dioxid than the 

 s;inie soils bearing other crojis. This is attribuliHl to the fact that iiotatoes and 

 legumes have a higher rate of respiration than other plants. 



The a])plication t»f barnyard nuinure is ininally as effei-tive as the ro»)t action 

 ill increasing the carbon dioxid content of soil air. 



The content of radio-active emauations in soil air, A. Oockkf, (P/ii/.*. 

 /.txdir., 9 (I90S), \o. 9, pp. 30 ',-306). —MviXMirvim^uls of the emanations in soil 

 to a depth of 1 mett'r showed wide variations with different conditions of the 

 soil and weather. 



The absorptive power of a cultivated soil. .7. Koskx and C. Hki.(.kr (lint. 

 <lti:.. ',i; ( I'.Kist. \i,. .i. ii/i. J^', Jj;i, figs. ./ 1 . — Kxperiments with wheat see<llings 

 grown in solutitjns uf different concentrations of dlsodimn phosphate, potassium 



