April, wo:.] LOEW & ASO.— ON PHYSIOL. BALANCED SOLUTIONS. 69 



able development of plants depends among other things upon 

 a certain quantitative ratio of lime to magnesia available to 

 the root. 13 



We have proved by water, sand and soil culture that an 

 excess of lime as well as an excess of magnesia beyond that 

 best ratio,— the lime factor — depresses the yield of various crops 

 more or less and have pointed out that the determination of 

 magnesia in partial soil analyses is as important as that of 

 lime — but thus for not much attention was paid to this im- 

 portant principle. The law of physiologically balanced solutions 

 was clear before our mind, and no doubt also was this law 

 regarded by Godlewski, Schrotter and others when they 

 tried to find by field experiment the best ratio of nitrogen to 

 phosphoric acid and potassa for certain crops. 2) 



" Heavy doses of strongly nitrogenous manures also neces- 

 sitate heavy doses of phosphoric acid to annihilate the injurious 

 effect of nitrogen," is a statement copied from a book just be- 

 fore us ; similar utterances are numerous in agricultural reports. 

 We must call attention to this, because that law of physio- 

 logically balanced solutions was recently claimed as a new 

 discovery.^ 



There may be a slight distinction made between a physio- 

 logically balanced solution for the maintenance of life only and 

 one which would insure the best development of plants; only 

 the latter is of course of importance. 



As that author further did not distinguish different pheno- 

 mena relating to this subject, we must enter upon a further 

 discussion. 



i) Cf. Flora, 1892 p. 381; ibid. 1903 p. 498 and 1905 p. 336; Landw. Vers.- 

 Stationen 1892, vol. 41 p. 467 ; Landw. Jahrbucher 1902 p. 561; ibid. 1905 p. 131 and 

 1906 p. 527; Zeitschrift f.d. Landw' Versuchswesen in Oesterreich, 1905. Cf. further 

 Loew and May, Bui. No. 1 Bureau of Plant Industry, Washington 1901; and the 

 Bulletins of this College, vol. IV p. 361-381; ibid. V p. 495-502; ibid. VI, p. 97-124 

 and p. 347 ; ibid. VII p. 8-12 and p. 57-65. 



2 ) Also here at this College some years ago an experiment was made by Bahadur 

 to find the most suitable ratio of N to P 2 O s for barley in soil culture) cf. this Bulletin 

 VI, No. 4). 



3 ) As physiologically balanced solutions were mentioned by that author blood 

 and sea water. 



