190 
JOHN W. SHIVE AND WILLIAM H. MARTIN 
solution of the corresponding series of water cultures which produced 
the highest dry weights of tops and of roots. These volume-molecular 
partial concentrations are: KH2PO4, 0.0108 m.; Ca(N03)2, 0.0130 m.; 
and MgS04, 0.0100 m. This set of salt proportions is not at all the 
same as that which produced the highest yields of tops or of roots in 
sand cultures during the early growth period, from germination to 
flowering. 
The results here presented are brought together in the following 
table which gives also the dry weight yields of tops, roots, and seeds, 
expressed in terms of the corresponding yields from Knop's solution 
and from Tottingham's best solution for wheat tops, taken as unity. 
Each of these data represents the averages from two corresponding 
series. 
Relative Dry Weights, and Salt Proportions Producing Maximum Yields of Buckwheat 
with an Optimal Series of Three-salt Solutions, in Water Cultures and in Sand 
Cultures, during Two Different Physiological Growth Periods 
B uckwheat 
grown to 
flowering 
(early growth 
period) 
B uckwheat 
grown to 
maturity- 
(late growth 
period) 
Water,cultures{iToP^\ 
Sand cultures {\^^ 
Water cultures 
Tops 
Roots 
^ Seeds 
( Tops 
Sand cultures s Roots 
^ Seeds 
Volume-molecular Partial 
Concentrations 
KH2PO4 
0.0144 
0.0144 
0.0144 
0.0180 
0.0108 
0.0108 
0.0108 
0.0108 
0.0108 
0.0108 
Ca(N03)2 
0.0052 
0.0052 
0.0052 
0.0104 
0.0130 
0.0130 
0.0078 
0.0130 
0.0130 
0.0130 
MgS04 
0.0200 
0.0200 
0.0200 
0.0050 
0.0100 
0.0 1 00 
0.0200 
0.0100 
0.0100 
0.0100 
Yields of Tops, 
Roots, Seeds, Rela- 
tive to Those from 
Knop's 
Solution 
taken as 
I.61 
1.58 
1.38 
1.47 
1.40 
1.50 
1.28 
1.40 
1.27 
1.24 
Totting- 
ham's So- 
lution 
taken as 
1. 00 
1.33 
1.27 
1.25 
1. 16 
1-35 
1.39 
1.74 
1.26 
1.26 
1. 17 
From these results it is at once clear that the salt proportions re- 
quired to produce the best physiological balance for buckwheat during 
the two different growth periods here considered differ markedly and 
in the same manner with water cultures and with sand cultures. It 
appears that the best physiological balance of salt proportions for 
buckwheat with this optimal three-salt series of solutions is not greatly 
disturbed when these solutions, with frequent renewals, are employed 
in sand cultures. This is clearly shown by the fact that the salt pro- 
