DIURNAL CHANGES IN THE ION CONCENTRATION OF THE SUPPLY AND RETURN WATER OF A TOMATO CROP GROWN ON ROCKWOOL

Ion concentration measurements were carried out on a closed loop nutrient supply system of a tomato crop grown on rockwool.
For this purpose samples were taken from the supply water and from the return water of the water supply system.
The samples were analyzed off-line by a chemical laboratory and on-line with a titro-analyzer.

It is the object of this project to gain experience with ion selective measuring techniques in general and to study the use of a titro-analyzer in particular, as the sensor in a measurement and control loop.
The potential usability of this instrument should be determined, for the control of ion concentrations in the nutrient solution for a crop grown in a soilless culture system.

The paper emphasizes that less complicated sensing techniques are needed before ion selective measurement and control should be introduced in practice.
It explains the need for models, which correlate the uptake of non-measurable ions to measurable ions.
The paper deals with some problems related to the instruments used during the experiments.

I International Workshop on Sensors in Horticulture

G. Kupers, J. van Gaalen, Th.H. Gieling, E.A. van Os

titro-analyzer, ion selective electrode, ion concentration, nutrients, soilless culture, rockwool, nutrient control, NFT

https://doi.org/10.17660/ActaHortic.1992.304.33