ISHS Acta Horticulturae 323: Symposium on Soil and Soilless Media under Protected Cultivation in Mild Winter Climates
CROP NUTRITION IN HYDROPONICS |
| Author: | P. Adams |
| Keywords: | Tomato, cucumber, light, temperature, humidity, aeration, salinity |
| Abstract:
Concern about pollution of the environment by waste nutrients has lead to increasing interest in recirculation of the nutrient solution. In order to optimise the uptake and minimise the wastage of nutrients, inputs must match uptake and good quality water must be used. Nutrient uptake is generally proportional to the concentration of nutrients around the roots but, in flowing solutions, plants are able to make good growth over a wide range of concentrations. Environmental factors can also have a profound effect on nutrition. With tomato and cucumber, the uptake of water, N and K were highly correlated with solar radiation and air temperature while P uptake increased with root temperature. High humidity decreased the Ca and K contents of tomato leaves but increased the Ca content of the fruit. Increasing the salinity by adding NaCl to the solution decreased the K content of tomatoes without adversely affecting the quality. High salinity always decreased the Ca content of tomatoes irrespective of the salts used; blossom-end rot was induced more easily by high levels of major nutrients than by NaCl. | |
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