The UK narcissus industry largely relies on planting bulbs on a ridge system using modified potato planters. While having the advantage of familiarity, it means bulb spacing and orientation are not well controlled compared with bed systems in the Netherlands.
This AHDB Horticulture funded studentship focuses on two main areas: planting at precise depths, spacing and orientation; and precision fertiliser placement in terms of both when and where it is placed. The aim is to improve yield, quality, uniformity and harvesting efficiency, either by modifying the current technique or developing new ones.
An initial audit of growers revealed an interesting observation - bulb orientation at planting has no effect on subsequent growth, with bulbs said to right themselves when growing. Given the influence that this might have on yield and quality, an experiment was designed to observe this and to deduce the mechanism by which it occurs.
Narcissus have been shown to have contractile roots capable of pulling bulbs deeper into soil. The expectation was that bulbs planted sideways or fully inverted would use these roots to right the growing shoot. However, no evidence was observed of the bulbs self-righting, nor of contractile roots pulling bulbs deeper into the growing medium.
Inverted bulbs simply grew a shoot that curved round and headed upwards against gravity. Some sideways or inverted bulbs showed roots growing between the bulb scales or under the tunic and breaking out of the side of the bulb.
The first year of this project was devoted to gaining an understanding of the industry, so that experiments could be tailored correctly, and establishing the field trials. The main experimental data will follow over subsequent years.
For details on all AHDB Horticulture activity, see horticulture.ahdb.org.uk