Among many factors influencing the crop growth and utilization by plants of nutrient elements from solution of a considerable importance are the properties of the substrate.
It is a common practice when conducting tests in vessels to apply one and the same dose of salts per I 1 of solution in water cultures or per 1 kg of sand in sand cultures whereas in these cases quite different conditions for plants’ nutrition are created.
In sand cultures no such intensive nutrition of plants can be achieved as in water cultures.
In table I data are represented on assimilation of nutrients by cucumbers during 37 days under various concentrations of the solution in sand and water cultures (Zurbicki 1963).
Absorption of nutrient elements by cucumber plants grown in sand or solution cultures with various concentrations of nutrient solution (meq per I plant)
|
Substrate |
Concentratio of the solution |
Assimilated by plants
|
|
(meq/1) |
N |
P |
K
|
Sand |
3.3 |
0.49 |
0.07 |
0.09
|
Water |
3.4 |
6.00 |
1.06 |
1.29
|
Sand |
7.7 |
1.60 |
0.23 |
0.27
|
Water |
6.9 |
8.16 |
1.32 |
2.46
|
Sand |
15.3 |
4.26 |
0.65 |
0.92
|
Water |
14.9 |
8.38 |
1.38 |
2.68
|
When applying the same amounts of salts per a vessel in solution culture with salts concentration 3.4 meq/l the plants assimilated more elements than in sand with concentration of 15.3 meq/l, i.e. 5 times greater than in water.
Therefore, growth of plants in solution culture is always ahead of that in sand. (Fig.
I).
