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THE EFFECT OF IRRIGATION SYSTEM AND PEAT TYPE ON THE PRODUCTION OF HEBE “MRS WINDER”
A fifth system of overhead irrigation with controlled release fertilizers was also included.
The five systems were replicated four times in 20 independent beds, measuring 5 x 2 m, each with its own reservoir.
Rooted plants of Hebe “Mrs.
Winder” were placed in the beds, in 2 liter pots, in May.
Within each system, peat substrates with air filled porosity (AFP) values ranging from 6% to 25% were used.
These peat substrates were achieved using blends of graded peat particles.
The plants were assessed in November and again in April when the experiment terminated.
The largest plants were produced in the ebb and flood beds especially where liquid feeding was used.
Plants in the capillary beds were smaller and accumulated higher nutrient levels, particularly Ca and Mg, in the pots.
Plants in the overhead spray beds were similar in size to those in the capillary beds but scored more highly for marketability because of their superior color.
Rooting through was a problem particularly with ebb and flood irrigation even though the beds were covered with Mypex sheeting.
This did not occur on the capillary beds.
Ebb and flood irrigation was the most water conserving of the systems while overhead irrigation was the most wasteful.
Peat grade had only a small effect on plant performance with the best results being obtained where the easily available water (EAW) content was high.
The year however was exceptionally warm and dry and the experiment is being repeated.