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



293 



the loam is more tolerant than either of the extremes and that the lighter 

 loam soils are more tolerant than the heavier. This is especially notice- 

 able with the carbonates. 



sond 



sond - 

 loam- 



sond- 

 loom- 



sond- 

 loom- 



■sand- 

 loam- 



sand- 

 loam- 



sand- 

 loam- 



DOf COj in p.p.m. of dry 501/ 

 Joo ijooo 3.000 snoo 7.000 10.000 



€€^:xxxxxaxx:) 

 '€©©€cxxxxxx:)0 



60% 

 ■20% 



60V„ 

 ■fO% 



c»©@xxxxrxx) 



loam -90% 

 cloy -10'?, 



loam-so"!!, 

 cloy —20-% 



loam-io'^o 

 cloy—jo-si 



loam—60'% 

 day -40% 



ham - JO ^ 

 clay - JO'T. 



loom- tof, 

 clay - eof. 



loom- JO f„ 



cloy -707.. 



mxs^^^m^&^^^ico 



loom-zo'7. A^/^^/^i 

 clay- 60-/. \^jA^y<i:>" 



loam - 10 "7, 



clay— 10 'f. 



"•^ ©@^XIXIXX)CXOOCO 



= one plant 



■= o-i^rndr'/ matter 



Fig. 6.— Diagram showing the number of wheat plants up and the dry matter produced in 21 days in soils 

 of different texture containing sodium carbonate added in various concentrations. Soils maintained at 

 an equivalent moisture content. 



It was noticed in this experiment that at 20 per cent moisture content 

 the sand was nearly saturated, while the clay was comparatively dry. 

 In order to overcome the effect of the varying moisture relations when 

 soils of all textures were maintained at 20 per cent, experiments were 



