[SHUTT- smith] 



CONTENT OF SOILS 



241 



Discussion of Results. The alkali of these groups presents a 

 different case from the two series already discussed, the harmful salt 

 being carbonate of soda, "black alkali." 



Group 1659. Good growth. In parts of the field where a good crop 

 was growing the concentration in the first six inches is -168 per cent 

 carbonate of soda, with a considerable heavier impregnation in the 

 lower members of the group. 



Group 1658. Poor and meagre growth. In A (O'-O — 0'-5) the 

 impregnation is -227. The crop showed a very distressed appearance, 

 and evidently the limit of tolerance had been passed. 



Group 1657. No growth. In A (0'-0-0'-5) the carbonate of 

 soda is -272 and sulphate of soda is -368. As is frequently the case 

 with black alkali, the highest concentration is found in the surface soil. 



It is interesting to note that when carbonate of soda is present 

 very small changes in the percentage very materially affect the crop. 

 Judging from these results 0- 1 per cent to 0- 15 per cent is the limit for 

 Western Rye grass and it is generally conceded that this grass is more 

 resistant to alkali than many other crops. 



Oats 



Series IX, Lot 27-476, Summerland, British Columbia. 



A series of three groups was collected on July 27th, 1918, from an 

 oat field about 4 miles south-west of Summerland, Okanagan Valley, 

 B.C. The area has been under irrigation for a number of years. The 

 surface soil is a brown loam of good quality. Sub-soil of clay loam 

 with some gravel. The water table was from 2 • to 2 • 5 feet from sur- 

 face. 



Series IX — -Oats 



