AMERICAN 
JOURNAL OF BOTANY 
Vol. II April, 1915 No. 4 
A THREE-SALT NUTRIENT SOLUTION FOR PLANTS 
John W. Shive 
From a survey of the literature bearing on the growth of plants 
in nutrient solutions, it appears that the experimental work most 
nearly approaching logical completeness is that recently carried out 
by Tottingham.i This writer employed 84 different solutions, all of 
approximately the same total osmotic concentration but each solution 
differing from all the others in its proportions of the four nutrient 
salts, mono-potassium phosphate, potassium nitrate, calcium nitrate, 
and magnesium sulphate. Besides these salts each solution contained 
the usual trace of iron, as ferric phosphate. Tests of the 84 different 
proportions of the nutrient salts, with total osmotic concentration 
(2.50 atmospheres diffusion tension) about the optimum for young 
wheat plants, showed that the best solution for the growth of tops 
(during the first four weeks after germination) contained the four salts 
in the following volume-molecular concentrations: KNO3, .0049m.; 
KH2PO4, .0130m.; Ca(N0.s)2, .0144m.; MgS04, .0145m. The solu- 
tion giving the greatest dry weight of tops showed an improvement 
over Knop's solution, of the same osmotic concentration, of 11 percent 
on the basis of dry weight of tops grown in Knop's solution. The 
solution above described is Tottingham's best solution for tops, and 
may be regarded as the most reliable standard nutrient solution for 
wheat during its first four weeks of growth, so far worked out. The 
present writer has repeated the test of Tottingham's optimal series 
of solutions and of Knop's solution (all with osmotic concentration 
of 2.50 atmospheres) with wheat, and the results are in very satis- 
factory agreement with those obtained by Tottingham. For tops, 
1 Tottingham, W. E. A Quantitative Chemical and Physiological Study of 
Nutrient Solutions for Plant Cultures. Physiol. Researches i: 133-345. 1914- 
[The Journal for March (2: 111-156) was issu2d 23 Ap 1915.] 
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