52 TOXIC LIMITS OF ALKALI 



sistance of the plants was about in the order given, barley 

 being most tolerant. About 5000 parts per million of 

 sodium carbonate or sodium chloride was fatal to the 

 germination of these plants, and, excepting that peas 

 were the most resistant to sodium carbonate and alfalfa 

 was weakest for those salts, the order of toxicity was 

 about as .given above. 



Oats and mustard were found more resistant than flax 

 for sodium chloride and sodium sulphate in pots of sand 

 containing 315 to 1889 parts per million of these salts. 

 Some influence of sodium sulphate was perceptible at the 

 higher concentrations and the sodium chloride caused 

 injury to the oats and mustard in the larger quantities. 

 Wheat, oats, and peas failed to grow in soils containing 390 

 parts per million of chlorides but survived in the presence 

 of 10,000 parts per million of total salts. Wheat and oats 

 could withstand 20,000 parts per million of total salts 

 where the chlorine content was less than 1250 parts per 

 million. 



Claudel and Crochetelle (12) found that sodium nitrate 

 in concentrations of 2000 parts per million prevented the 

 germination of buckwheat and beans, injured or checked 

 the germination of beet seed, and badly injured those of 

 clover. However, it had very little effect on wheat and bar- 

 ley seed. Buckwheat was considerably, and clover slightly, 

 affected by 1000 parts per million. Barley was the only 

 crop able to withstand 5000 parts per million of this salt. 



From the above discussion of the effects of alkali in 

 sand on plants, it is seen that where allowance is made for 

 the difference in the method of arriving at the toxic limits, 

 the results are fairly uniform when compared with those 

 of solution determinations. The two salts, sodium car- 

 bonate and sodium chloride, are nearly the same in toxicity, 



