A new three-year research project aims to improve the production and sustainability of the NSW north coast’s rapidly expanding blueberry industry.

NSW DPI soil scientist Justine Cox said blueberries were the fastest growing horticulture industry on the NSW north coast but little was known about the effects of common soil management practices used by the industry on soil health and productivity.

'The blueberry industry has expanded rapidly in recent years and is now worth more than $20 million to the north coast economy,' said Ms Cox who is based at Alstonville’s Centre for Tropical Horticulture.

'The plants are grown in mounded rows to improve water drainage and root growth, and growers cover these mounds with a plastic woven weedmat to reduce weeds and retain soil,' she said.

'It is not known if this method has any beneficial or adverse effects on long term productivity and soilhealth.

'We will trial the effects of plastic weedmat, a biodegradable weedmat and woodchip mulch on the soil environment, plant growth, health and berry yield.

'The experiments will be carried out in two orchards, one at Wollongbar and the other near Woolgoolga with a southern high-bush variety called Star.'

Ms Cox said new plantings would be established to measure the soil physical, chemical and biological environment, water relations and plant health and yield.

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'Weedmat protects from soil loss, increases temperatures and contains fertigated nutrients in the rootzone. Biodegradable weedmat also offers this, while slowly breaking down to safe byproducts, reducing disposal costs and the environmental impact of the plastic.

'Woodchip offers weed protection while contributing valuable carbon to the system. There is less of a barrier between the soil and the external environment.

'A range of soil health indicators will be measured over three years, including microbial activity, labile carbon, pH, nutrients, compaction and soil aggregate stability.

'Soil temperatures will be monitored, as well as root growth, plant growth and health, and of course blueberry yield. The growers involved in the project will play a part in measuring the plant factors during the experiment.'

This experiment will bring together the information required to assess the long term sustainability of different management options.

'We will also be able to link good berry growth with soil factors or a particular production system.'

Contact: Justine Cox, Alstonville on 02 6626 2400.

This story appears in Agriculture Today.