Nov.4 i9i8 Soil Factors Affecting the Toxicity of Alkali 295 



As determined by several duplicates of this method, 10 per cent 

 moisture in the sand, 27 per cent in the clay, and 50 per cent in peat, 



PoCl in p.p.m of dry soil 



400 1,000 2.0 00 J.OOO 4;000 



no /(^^/i^i^f' 

 garden soil \ 



garden soit,-^^^^ 



garden soil v^l^^i^^^i?^*; 



10 ^o 



garden soil \^£^l^^^^y^^ 



garden soil ^^Jp^^^^^c^^THA^^^^^^^^I^^^j^^^ 



■zo% /^^,^££i\f 

 garden soil \^«y*?3^^ 



■ one plant ■ i« ^■o.i^m- drymalttf 



noj COj in p.p. m. of dry soil 



500 1,000 0.000 5.000 7,000 10,000 



no ~ ' ' ' 

 garden soil ' 



garden soil 

 5Z 



garden soil. 



10% 

 garden soil 



I5Z 



garden so/I ^ 



20 fo 



garden soil^^.f_^ 



• = one plant ""^^ = aigm- dry motttr 



fla^SO^ inp.p.m.of dry soil 



SCO 1.000 MOO 5,000 7.000 10,000 



garden so// ^^^^^^^^^y^Z^f^l/Kiy^^i:/^^ 



garden soil ' 



garden soil V^y/ 



garden 3oll\^f^'Jy^ziy^iy<Iy^^y^^^ 



15% 



garden soil ' 



garden sod ^^J:^A^^f^i^^l:^l:A:y^ 



• '^ one plant ■— ■— = 0-1 jm- dry matter 



Fig. 8. — Diairram showing the number of wheat plants up and the dry matter produced in 21 days in sand 

 with different amounts of garden soil contain ing sodium chlorid, sodium carbonate, and sodium sulphate 

 added in various concentrations. Moisture content maintained at 20 per cent throughout. 



used in later experiments, was found to be equivalent to 20 per cent in 

 the loam. As worked out later on the moisture-equivalent centrifuge, 



