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



289 



It was found that the dry weight at harvest gave the best figures for 

 comparison. The number of plants germinated, the average number of 

 days required to germinate, the average height of plants, and the aver- 



DaCI inp-p. m- of dry soil 

 ^00 1.000 zpoo J.OOO 



sand 



sand- 90% 

 loam-io'f,. 



sand- 60% 

 Joam—zo-f. 



loam - J0<\^^^PKlAi'yK^t^^ 



loom 



loam— 90'/', 

 clay— 1 0"/. 



loom-so-/, 

 clay— 20< 



/OQm-70f. 



clay- J05J 



loom-eo-f. 

 cloy— 40 "f. 



loam—jofo 

 cloy— J0< 



/oam-'i-O'Z 

 clay— 6 0^.^^ 



loom-joii 

 cloy— 7o< 



loam-10% 

 cloy-90% V^HjA^ 



one plant 



■ o-Kjin- dry molt er 



Fig. 2. — Diagram showing the number of wheat plants up and the dry matter produced in 21 days in soils 

 of different texture containing sodium chlorid added in various concentrations. Moisture content 

 maintained at 20 per cent throughout. 



age number of leaves were also used as indicators of plants growth. In 

 these experiments only the three most important alkali salts, sodium 

 chlorid, sodium carbonate, and sodium sulphate, were used. The rela- 

 tive toxicity of most of the alkali salts was reported in the earlier paper. 



