Nov. 4, i9i8 Soil Factors A fjecting the Toxicity of Alkali 317 



by water extractions. This extraction in experiments of this kind does 

 not show all of the alkali carbonates that have been added. In averaging 

 all the determinations it will be seen that less than half of the salt added 

 was extracted. While this is not enough to change the results to the 



DoCI inp-p-m-ofdry soil 

 ^00 1000 2.000 J.000. ffioo 



» „s.axxx)Ocxxx)gg 



moisture ' 

 moisture ^ 

 moisture 



JOfi 



moisture 



• = one plant •— • = o-igmiry matte f 



DojCOj inp.pm ofdrysoil 

 500 1.000 J.000 SjOOO 7,000 IQOOO 



moisture \jK^jK^X.jKjKy^^ 



moisture ' 



moisture 



29% 



moisture 



J2% 



moisture 



' = one plant 



= o-ifm- (fry matter 



Po^SOi. in pp. m. of dry soil 

 soo 1.000 jjooo j.ooo zooo moo 



moisture V_A_A_JLJLJvJwWWvJ^ 



SJK 



moisture 



■moisture \^^^^z^f<vy^zy^<:y<bKy^,y^ 



moisture ^<5 



Jv2« 



moisture _____ 



• = one plant ^^^ = o.ignt- dry matter 



Fig. 26. — Diagram showing the number of wheat plants up and the dry matter produced in 21 dajs in 

 loam aud manure maintained at different moisture contents and containing sodium chlorid, sodium 

 carbonate, and sodium sulphate in various concentrations. 



customary statement that the carbonates are twice as toxic as the 

 chlorids, it shows possibilities in this direction. The method of extracting 

 was as follows: Fifty gm. of the oven-dry soil were added to 500 cc. of 

 distilled water and stirred with a wooden paddle for five minutes. The 



