The
              Report
No. 15: Better waxflowers and Protea through nutrient management

THE FULL REPORT

This short report is a summary of the unpublished full research report Development of Nutrient Management Technology for Improved Quality, Yield and Postharvest life of Australian waxflowers, Protea and Silvan Red by N.A. Maier. A photocopy is available from RIRDC on (02) 6272 4029.

Introduction

Improved nutrient management strategies offer an opportunity to significantly improve the productivity, quality and post-harvest life of waxflowers and certain species of Protea.

And by following improved nutrient management strategies growers will help ensure the delivery of high quality products to export markets.

This key recommendation arose from a study which examined nutrient management strategies aimed at improving the quality, yield, and post-harvest life of Australian waxflowers Protea Pink Ice and Leucadendron Silvan Red.
 

Background

The aim of this research project was to develop specific guidelines that would help growers meet the nutritional requirements of their crops so they can improve the quality of their products and the industry’s efficiency.

By developing and devising nutrient management strategies, growers may be able to address problems such as vegetative growth above flowers prior to harvest, leaf yellowing, and premature leaf and flower abscission.

Addressing these problems will help improve the quality of waxflowers being exported and thereby help ensure the industry’s long term viability.

An earlier study, funded by the Australian Protea Growers Association (APGA), identified variations in nutrient concentrations and potential deficiencies. These were seen as important issues affecting management practices and the post-harvest quality of Proteas and Leucadendrons.

It was against this background that the Rural Industries Research and Development Corporation and the APGA commissioned research into this area.

The project looked at developing nutrient management technologies to improve the quality, yield, and post-harvest life of Australian waxflowers Protea Pink Ice and Leucadendron Silvan Red.

The research was conducted by the South Australian Research and Development Institute under the leadership of
Mr N Maier.

Objectives

The study’s key objectives were to:

Recommendations

For waxflowers grown in siliceous sands (soils containing high levels of silica), the report says annual applications of 80 to 160 g of nitrogen per plant are required to maximise productivity.

This would result in increased shoot growth, greater tip growth and increased vase-life, although the extent of the increased vase-life varies between varieties.

To determine the most effective nitrogen strategy in differing areas, growers have to take into account soil type—particularly levels of residual nitrogen fertility, harvest periods, annual growth cycles and flowering times.

Applying nitrogen also decreased the incidence of yellow, poorly coloured foliage. The report said that defoliation during flowering may be associated with nitrogen deficiencies.

In relation to potassium, the report recommended an annual application of 20 g of potassium per plant for waxflowers grown in acid leached sands. This would help ensure long term productivity in the plants.

The study found that there were no yield increases in response to applications of phosphorous.

The study also examined the yield and quality responses of Protea and Leucadendron species to applications of nitrogen, potassium and calcium.

It found that annual applications of 25 or 50 g of nitrogen per plant increased the total weight of stems harvested from King Proteas. However, applications of ammonium sulfate, potassium sulfate or gypsum did not significantly affect the number or size distribution of stems harvested from Leucadendron Silvan Red and Safari Sunset and Protea Pink Ice.

For flowers grown in acid leached soils, the researchers suggested applications of calcium and nitrogen of up to 20 to 30 g per plant and applications of magnesium and potassium of up 10 to 15 g per plant.

For irrigated Protea and Leucadendron crops grown on siliceous sands, the study recommended annual applications of nitrogen and calcium of up to 20 to 30 g per plant and applications of magnesium and potassium of up to 10 to 15 g per plant.

Conclusion

In their conclusion, the authors recommended that further research be undertaken into nutrient management strategies. They said the additional research projects should: