Inter-row crops

By Jacqueline MacLaurin, Vineyard Technician, Wither Hills

The late spring conditions have been perfect for the germination of seed sown and for the growth of those crops sown in early spring.

In initial stages of the project, in late winter, our project advisor Bart Arnst came to visit the vineyards that are part of the project. One of my first questions in regards to the Sauvignon Blanc block was, ‘What shall we sow in the inter-row?’ This was a pertinent question based on the previous management of the block – in the past, this block had a broadcast herbicide (glyphosate and goal) applied pre-bud burst to achieve a ‘bare earth’ as a means of frost control. This management technique had been practiced as far as we know ever since the initial planting of the vineyard – approximately ten years ago. It had led to a compact, and visually lifeless soil surface. The surface litter was primarily vineyard trash – vine prunings that had accumulated on the surface over time, as very little breakdown of this had taken place, leading to a large build-up of carbonaceous material. To aid in the breakdown of the trash, Bart suggested planting Omaka Barley. The barley also has a good root structure and so would help bring some structure back into the soil, and will withstand tractors driving over it. The aim for the season is to top it in the summer and disk it back into the ground post harvest. The barley was sown at a rate of 120kg/hectare.

Another inter-row crop more commonly seen in vineyards over the summer months is a buckwheat and Phacelia mix. This mix is primarily planted to attract beneficial insects such as lady bird beetles, hoverflies, wasps, and flies, which feed on the nectar provided by these plants. The structure of the plant also provides other benefits in the vineyard system – Phacelia has a tap root, helping to open up compacted soils and providing good ground tilth. We have sown buckwheat at 35kg/hectare and Phacelia at 3kg/hectare, in every tenth row.

Our aim in autumn is to sow a herbal ley as a permanent inter-row sward, with the idea of having a mixture of species with different rooting depths, including some with nitrogen-fixing abilities, and some to provide a source of food for beneficial insects.

Vineyard trash covering the Sauvignon Blanc inter-row after years of herbicide, Sept 2011

Omaka Barley cover crop in the organic Sauvignon Blanc block, Nov 30th

Following the field day in October comments arose regarding the Pinot Noir blocks chosen for the project. The organically managed Pinot Noir block was planted in vines trained in both spur and cane training systems whilst the conventionally managed block was all under a cane pruned system.

To decrease the number of variables that may occur when monitoring costs, irrigation needs, pest and disease levels etcetera, we have chosen to decrease the area that is part of the Focus Vineyard project. The Pinot Noir blocks now part of the project are Taylor River Block 11, managed conventionally – 2.05 hectares, Clone 667 on Schwarzman rootstock; and Taylor River Block 26, managed organically – 2.09 hectares, Clone 667 on 3309 rootstock. Both blocks are pruned to 2 cane, both were planted in 2008, both are likely to be cropping at the same level and destined for similar treatment in the winery.