Joseph Marks calls himself ‘an ecologist with a passion for wine.’
So his current project – investigating how under-vine cover crops affect arbuscular mycorrhizal associations, soil organic carbon composition and soil carbon stocks – is a marriage made in heaven.
Joseph is the inaugural recipient of the Dr Tony Jordan OAM Award, which recognised the most outstanding applicant in last year’s Wine Australia PhD and Masters by Research Scholarships.
Applications for the 2021 scholarships – which aim to support and attract postgraduate students to the fields of wine, viticulture and wine business research – opened this month.
Joseph said growers were increasingly looking at more sustainable options to manage their soil and vines, while at the same time decreasing the overall reliance on herbicides, pesticides and fertilisers.
‘One such method is to plant cover crops in the vineyard. Planting in the mid-row has been tested many times, however, not a lot of testing has been conducted on cover crops planted directly beneath the grapevines themselves – this is what we’re looking at.’
Joseph said cover crops are non-consumable plants that offer multiple benefits to the soil and therefore, the grapevines.
‘My project looks to test a few of these potential benefits on vineyard soil from underneath seven different treatments: five types of cover crop and a straw mulch against a traditional herbicide-managed bare-earth treatment (the control).
‘Essentially, I want to know if these cover crops increase the amount of beneficial fungi in the soil’, said Joseph.
‘Certain fungi (known as arbuscular mycorrhizal fungi) interact with plant roots in a very positive way – increasing their ability to find nutrients in the soil. Having tested this hypothesis, we found that the potential for plant roots to form these beneficial associations with the fungi was high in all treatments – a win for both cover crops and the traditional practice.’
As always, however, Joseph said further testing was needed to answer the question more definitively.
‘At the moment I’m looking closely at how cover crops affect the organic carbon levels in the soil. This is extremely important for soil health as organic carbon helps to provide structure to the soil, as well as many other benefits.
‘Moreover, soil is a great storage for atmospheric carbon, which is fantastic news for the climate.
‘My hypothesis is that more plant cover will increase the amount of carbon in the soil because if we have more plants photosynthesising then we will also have more carbon being drawn from the atmosphere down into the roots and soil.’
Joseph said testing on this was the next focus of his research, and would begin soon.
‘Cover crops appear to reduce the need for herbicide and fertiliser use, which is beneficial for growers in terms of cost-reduction and also allowing the vineyard to become a more natural ecosystem.
‘Increasing soil organic carbon is also hugely beneficial to growers as it not only increases soil health and the long-term sustainability of the vineyard but also helps the environment by drawing carbon from the atmosphere and storing it in the soil.’
He said the notion of ‘sustainability’ could also help bolster the marketing potential of a winery.
Joseph said he was ‘hugely grateful’ to Wine Australia for their funding and support.
‘Applying for this scholarship was a way of expressing my passion and desire to take this path of research. The scholarship and operating funds have provided me both the freedom and opportunity to devote time and energy to something both exciting and practical’, he said.