Mary Dang, Lincoln University Master’s Student
Funding from the BPA has helped kick-start a Lincoln University study into the efficacy of using waste products from wine making to improve soil nutrients and vine performance in Marlborough.
Soil science master’s student Mary Dang is a member of the four-strong Lincoln research team looking at the waste reutilisation options for winery produced grape marc – the residual skins, seeds and stalks that remain after pressing.
Previously, Mary had completed a bachelor’s degree in Environment Management at Southern Institute of Technology. Her research into measuring GHG emissions from agricultural soils in the Waituna catchment earned her the top student award over three years.
The 12-month Lincoln University project, which started earlier this year, is being supervised by Dr Olaf Schelezki, Senior Lecturer in Viticulture, Department of Wine, Food & Molecular Biosciences at Lincoln University, along with soils expert Associate Professor Niklas Lehto, and Seth Laurenson from Blenheim’s Bragato Research Institute in an external advisory role.
Marlborough is home to 30,444 hectares of vineyard, collectively generating approximately 70,000 tons of grape-marc annually. Managing this large organic waste stream is challenging due to its potential to contaminate soil and waterways.
Among numerous waste reutilisation options recommended, thermally pyrolysed biochar (an eco-friendly soil enhancer) emerges as the most promising because of its potential to improve soil properties and carbon sequestration.
The Lincoln University study aims to examine the possibility of grape marc-derived biochar as a soil amendment for soil fertility improvement, vine drought resistance, and GHG emissions reduction in vineyards.
“I was drawn to this project of reusing biowaste from vineyards to improve soil fertility and sequester carbon and was thrilled to receive funding from the BPA,” says Mary.
“I think the project has a very practical basis – if the results show that biochar made from grape marc waste has positive effects on soil properties, they may have practical benefits for grape production grown on these particular soil types.
“Existing studies often focus on other crops or in a general agricultural context, leaving critical questions unanswered regarding the specific impacts of grape marc-derived biochar on the soil fertility of different soil types in vineyards, and the potential role of biochar in mitigating carbon emissions,” she says.
“The study aims to address this gap by providing a focused analysis of biochar’s potential in vineyard-based soils, emphasising its effects on soil properties and grapevine tolerance under water stress, mirroring irrigation treatment.
“The work is expected to offer some insights that can guide future studies and practical applications in sustainable viticulture.”
The project will conduct a life cycle assessment of the carbon footprint of grapevine production, a chemical and physical assessment of soils amended with biochar, as well as a greenhouse pot trial to evaluate the effects of biochar on vine growth. The trial aims to work with conditions associated with the Marlborough region, with local soils specially transported to Lincoln, while the plant material is made up of Sauvignon Blanc vines.
“The assessment will ascertain whether the additional biochar can have a positive impact on the root development of vines,” says Dr Schelezki. “If proven, it could bring wide-ranging benefits to the New Zealand viticulture industry.”
The pot trial will begin next month, with close to 100 vines planted under greenhouse conditions.
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