[shutt-smith] 



"ALKALI" CONTENT OF SOILS 



95 



Discussion of Results. This is a case of white alkali, the per- 

 centages of sodium sulphate being accompanied with notable amounts 

 of magnesium sulphate. 



In group 1634 — good growth — "A" representing the first 6 

 inches is free, or practically free, of alkali. "B" (0'-5— I'-S) contains 

 a notable though not heavy impregnation, the percentage of sodium 

 sulphate slightly exceeding, according to most authorities, the usual 

 limit of tolerance for the vigorous growth of ordinary crops. In 

 "C" and "D" the alkali content is very large. 



Group 1633, representative of the area carrying a meagre and 

 poor growth, is of particular interest in indicating probably the limit of 

 tolerance for wheat. In the first 6 inches sodium sulphate is present 

 in an amount that would no doubt cause some distress but would not 

 inhibit all growth. But in B, C and D there is a very marked increase 

 in this salt, accompanied by magnesium sulphate, the totals being 

 such as to entirely prevent root extension. The crop is therefore 

 limited as to its foraging ground to the immediate surface soil. 



Group 1632 contains in A (O'-O — 0'-5) 1-741 per cent sodium 

 sulphate and -900 per cent magnesium sulphate. This concentration 

 of alkali is absolutely inhibitive for wheat and indeed renders the 

 soil worthless for common crops. The salts gradually decrease in 

 amount to the 5 foot depth, but in every instance the impregnation 

 greatly exceeds the limit of tolerance. 



Onions. — Series V. Lot 27-476, Summerland, B.C. 

 This series was taken from an onion 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 dark 

 brown sandy loam, well supplied with vegetable matter, the subsoil 

 a sand mixed with silty clay. Samples were collected August 25th, 

 1917. 



Onions. — Series V. Lot 27-476, Summerland, B.C. 



