Articles
MANAGEMENT OF FERTILIZATION FOR CONTAINER CROPS BY MEANS OF INDUCED PERCOLATE ANALYSIS
So, the cost of the culture and the pollution of the environment can be reduced to a minimum level by means of correctly calculated water and mineral supplies.
The substrate ionic composition is commonly determined by analysis of substrate sampling in containers.
This method is tedious and too slow to allow for rapid changes in the nutrient solution formulation in response to the plant needs.
A new method is proposed: inducing substrate percolate by nutrient solution supply, collecting and analysing the extract.
The aim of this paper is to compare the data obtained by the two methods.
An experiment was conducted with Thuja plicata cv. atrovirens growing in four litre containers filled with two substrates, sphagnum peat – perlite mixture (50/50 v/v) and French brown peat – perlite mixture (50/50 v/v). A complete nutrient solution was supplied to the two substrates with dripping system.
EC, pH, mineral water soluble contents were determined periodically in the substrate extracts obtained by the two methods.
Results show that the method of induced percolate gives a representation of substrate water phase similar to that of the substrate analysis so long as the daily evapotranspiration is less than the rainfall.
A difference occurs during hot periods.
It is probably due to the formation of a wet zone (bulb) inside the substrate volume.