58 TOXIC LIMITS OF ALKALI 



termining the salts in the soils. With laboratory experi- 

 ments, the same allowances must be made because of the 

 various complicating factors such as moisture content, 

 organic matter, antagonism of the salts, absorption, and 

 differences in tolerance of the plants at different times. 



REFERENCES 



1. BANCROFT, R. L. The Alkali Soils of Iowa. Iowa Sta. Bui. 177 



(1918) 



2. BREAZEALE, J. F. Effect of the Concentration of the Nutrient Solu- 



tion upon Wheat Cultures. Science, n. ser. 22 (1905), pp. 146-149. 



3. BUFFUM, B. C. Alkali. Wyo. Sta. Bui. 29 (1896), pp. 219-253. 



4. BUFFUM, B. C. Alkali Studies, III. Wyo. Sta. Rpt. 1899, p. 40. 



Also Rpt. for 1900. 



5. COUPIN, H. On the Poisonous Properties ot Compounds of Sodium, 



Potassium, and Ammonium. Rev. Gen. Bot. 12 (1900), No. 137, 

 pp. 177-193- (Abs. E. S. R. 12, pp. 717-718.) 



6. COUPIN, H. On the Poisonous Properties of Sodium Chloride and Sea 



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 190, figs. 3. (Abs. E. S. R. n, p. 24.) 



7. GUTHRIE, F. B., and HELMS, R. Pot Experiments to Determine the 



Limits of Endurance of Different Farm Crops for Certain Injurious 

 Substances. Agr. Gaz. N. S. Wales, 14 (1903), No. 2, pp. 114-120. 

 See also 16 (1905). 



8. HANSTEEN, B. The Relation of Plants to Salts in Soils. Nyt. Mag. 



Naturvidensk. 47 (1909), No. 2, pp. 181-192. (Abs. E. S. R. 23, 

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Landw. Ztg., 64 (1915), Nos. 19-20, pp. 478-508. (Abs. E. S. R. 35, 

 pp. 423-424.) 



10. HARRIS, F. S. Effect of Alkali Salts in Soils on the Germination and 



Growth of Crops. Jour. Agr. Res. Vol. 5 (1915), pp. 1-52. 



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12. HICKS, G. H. The Germination of Seeds as Affected by Certain 



Chemical Fertilizers. U. S. D. A. Div. Bot. Bui. 24 (1900), p. 15. 



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14. KEARNEY, T. H., and CAMERON, F. K. The Effect upon Seeding 



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 pp. 7-60. 



