Nov.4. i9i8 Soil F^ actors Affecting the Toxicity of Alkali 



305 



Additional organic matter seemed to increase the tolerance of the 

 soil for alkali if enough additional water was added to bring it up to an 

 equivalent moisture content, but increased the toxicity if the extra 



DaCL in pfxm. of dry soil 



3,000 



©QOOOOOOOOOO 



5% 



moisture 



10% 



moisture 



io-r. 



moisture 



25 7. 



moiiture 



» — ont plant ^"•^ -=a.jm. ary maltei 



na.CO, in p.p. m of dry soil 



500 IflOO 3,000 S.000 7,000 



10,000 



moisture 



10 V. 



moisture 



15 y. 



moisture 



iO 



moisture 



25 y. 

 moistute 



&xxjxxxrcco 

 ^msoooccccco 



Zr. ^mmccccccco 



*am cn» plant 



^mm 0.1 am. dry matter 



na,SOi in p. p.m. of dry soil 



!00 IPOO 3,000 S,009 1,000 10.000 



moisture wUyUUUULJw^ 

 10 y. ^£F^^^>Yii>^^£?V«JV^V"Y^Y^Y^^ 



moisture v2y<zy^^lT^zy<iy^<2M:yyi^ 



isy^ 

 moisture 



20 % 



moisture 



6.1 gm. dry matter 



jfl(,_ 17 —Diagram showing the number of wheat plants up and the dry matter produced in 21 days in 

 sand maintained at different moisture contents and containing sodium chlorid, sodium carbonate, and 

 sodium sulphate added in various concentrations. 



moisture was not added. The greatest effect was produced by the peat 

 probably because it was the finest and could be most thoroughly incor- 

 porated into the soil. The results were more noticeable in the case of 

 the carbonates than in that of the two other salts. 



