616 Journal of Agricultural Research vol. vi, NO. 16 



grown in sand, brown silt loam, dolomite, and soil containing 35 per 

 cent of magnesite showed calcium contents varying between 0.165 P er 

 cent and 0.547 per cent and magnesium contents varying between 0.132 

 per cent and 0.955 P er cent. 



(8) Acid extractions failed to remove all the calcium and magnesium 

 from the sand. There remained after the various extractions from 768 

 to 852 mgm. of calcium and from 540 to 960 mgm. of magnesium per 

 6,000 gm. of sand. 



(9) The plants possessed a decided ability to obtain calcium and mag- 

 nesium from sand extracted with strong hydrochloric acid, as borne 

 out by the following example: Three crops of alfalfa removed from acid 

 extracted sand 164.43 mgm. more calcium and 90.4 mgm. more magne- 

 sium than was contained in seeds similar to those planted. 



LITERATURE CITED 



(1) DASSONVILLE, Ch. 



1898. Influence des sels mineraux sur la forme et la structure des vegetaux. 

 In Rev. Gen. Bot., t. 10, no. 109, p. 15-25, fig. 13-14; no. no, p. 

 59-68; no. in, p. 102-124, fig. 23; no. 112, p. 161-170; no. 113, p. 

 193-199; no. 114, p. 238-260, fig. 27; no. 115, p. 289-304; no. 116, 

 P- 335-344; no. 117, p. 370-380, pi. 5-14. 



(2) DOJARENKO, A. 



1903 . Remarks on Loew's hypothesis concerning the r61e of lime in soils. (Ab- 



stract.) In Exp. Sta. Rec., v. 15, no. 2, p. 127. 1903. Original 

 article in Zhur. Opuitn. Agron. (Jour. Exp. Landw.), t. 4, kniga 2, 

 p. 183-187. 1903. Not seen. 



(3) GILE, P. L. 



1913. Lime-magnesia ratio as influenced by concentration. Porto Rico Agr. 



Exp. Sta. Bui. 12, 24 p., 4 pi. 

 (4) and AGETON, C. N. 



1913. The significance of the lime-magnesia ratio in soil analysis. In Jour. 



Indus, and Engin. Chem., v. 5, no. i, p. 33-35. 



(5) 



1914. The effect of strongly calcareous soils on the growth and ash composi- 



tion of certain plants. Porto Rico Agr. Exp. Sta. Bui. 16, 45 p., 4 pi. 



(6) G6SSEL, Fr. 



1904. Importance of calcium and magnesium salts for plants. (Abstract.) 



In Jour. Chem. Soc. [London], v. 88, pt. 2, Abstracts, p. 51. Original 

 article in Verhandl. Gesell. Deut. Naturf. u. Arzte, 75. Versamml. 

 1903, T. 2, Halfte i, p. 101-104. 1904. Not seen. 



(7) HASELHOFP, E. 



1893. Versuche iiber den Ersatz des Kalkes durch Strontian bei der Pflan- 

 zenernahrung. In Landw. Jahrb., Bd. 22, p. 851-861. 



(8) 



1913. Uber die Wirkung von Kalk und Magnesia bei der Ernahrung deJ 

 Pflanzen. In Landw. Jahrb., Bd. 45, Heft 4, p. 609-633. 



(9) HOPKINS, C. G. 



1910. Soil Fertility and Permanent Agriculture. 653 p., illus., maps. 



Boston, New York. 

 (10) JENSEN, G. H. 



1907. Toxic limits and stimulation effects of some salts and poisons on wheat. 



In Bot. Gaz., v. 43, no. i, p. 11-44, 33 fig- Literature cited, p. 42-44. 



