3i6 Journal of Agricultural Research voi. xv, no. s 



added, and that there is notable discrepancy between the carbonate 

 added to the soil and the amount as determined by water extraction. 

 It would seem that these might to a certain extent be offered as a mutual 



rioCt in p-p- m- ot dry soil 



^00 1.000 Z.00O 3000 ^.000 



tr.ODCCCCCCCCCO 



20 



moisture 



moisture ^ 



moisture 



moisture ^^SV^^S^'Cii^^^ 



@@#@©@@^^)©0O 



• =^ one plant ^^^ = oigm- dry matter 



DojCOj inp.p.m-ofdrYsoil 



SOO 1.000 3.000 6.000 7.000 lOjOOO 



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moisture 



22^. 



moisture 



moisture V^v^^SJ^^^ 



26y. 

 moisture ^^ti^^^'^^j/^y^^A^^ 



261! 



moisture _ 



• ■» one plant — ^^ =— o-igm-dry rnotter 



DoiSO^ inp.pmotdrysoil 



300 1.000 JjOOO J.0OO 7.000 lopQo 



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22n 

 moisture^f'i 



moisture 



moisture ^T^ 



2ef. 

 moisture Wvi 



• = one plant •— =o-ty/n</rY matter 



Fig. 25.— Diagram showing the number of wheat plants up and the dry matter produced in 21 days in 

 loam and peat maintained at different moisture contents and containing sodium chlorid, sodium 

 carbonate, and sodium sulphate added in various concentrations. 



explanation of one another. Neither of these peculiarities was observed 

 in our studies with sand. 



Practically all of the results showing the carbonates to be more toxic 

 than the chlorids have been obtained from studies in solutions and in 

 sand cultures or from field studies where the salt has been determined 



