Weighing up trellis systems

Dried Fruits Australia’s most recent field events have highlighted the range of trellis systems in use in the industry today.

Innovation is at the heart of the industry. The innovative Shaw swingarm trellis developed by Ivan Shaw revolutionised the dried grape industry and created a production system that allowed for fruit to be dried on the vine. Growers haven’t stopped there. A range of dried grape producers continue to test different options in pursuit of higher yields in production systems that suit their needs, Here we look at some of the trellis designs that are currently being used across the industry. From the common to the novel, we take a closer look at what it takes to operate properties using these different systems, as well as the crops these systems can yield.

Shaw swingarm trellis: Shaw swingarm trellis is the most common trellis system in the Australian dried grape industry today. Developed by Ivan Shaw, the system was designed specifically to allow for vine drying fruit.

Yields: DFA projects have proven that growers can consistently yield more than 10 tonnes per hectare with best practice management on this system.

Pros: The Shaw swingarm trellis separates replacement canes from cropping canes, and ensures replacement canes can grow up into the sunlight. This system can be mechanically summer pruned and harvested, with some growers also now using mechanised systems to winter prune.

Cons: Manual labour is still involved in tipping and pinning, and specialised equipment is needed. Conventional winegrape harvesters cannot be used for this trellis system.

Swinging pergola trellis:

Allan Long’s swinging pergola trellis – or narrow row trellis system – is a modified version of the Shaw swingarm trellis, incorporating elements from production systems in the US where fruit is grown on a fixed pergola system.

Vines are grown in 7ft rows, down from the traditional 11ft row.

A latch at the fruiting arm joins at the top of another fruiting arm to give structure and create a pergola in every second row.

Yield: This system has proven to be very high yielding, with Allan’s patch of Selma Pete taking out the 2022 Top Crop Award with a yield of 15.81 tonnes per hectare.

Pros: In addition to being very high yielding, pest and disease control is good because of good access to the fruit. Weed control is simple because sunlight is blocked out.

This system is manageable for a single operator on a smallerscale block. Six hectares can be managed by a single operator three days a week.

Cons: Specialised equipment is needed for wetting and harvesting, while cutting and pruning are done manually.

Vertical trellis:

The vertical trellis is less common in the Australian dried grape industry.

Peter Liakos grows Selma Pete, Sunglo and sunmuscat on the vertical system, where everything grows in one vertical line, with replacement canes growing loose and fruiting canes being rolled onto two wires. There is a loose wire and clip that holds everything in place.

Pros: Fruit can be harvested with a standard winegrape harvester, which is much more readily available. Replacement canes are free to grow upwards, receiving light, optimising potential yield. A suitable system if producers have good access to semi-skilled labour for manual work.

Cons: Manual cutting, manual winter operation, no comparative studies or data on yield capacity.

Biannual cropping pergola:

One of the more unique production systems in the industry, Allan Long has planted a small trial patch in a fixed pergolla trellis system, with biannual cropping.

Replacement canes grow in year one, sitting on top of a wire structure. In year one, water, fertiliser and pest and disease costs are reduced.

In year two, those canes produce fruit, and water, fertiliser and pest and disease outputs are higher.

Pros: Theoretically, the yield will double on harvest years. Most labour costs are in the production year with income being biannual.

Cons: Specialised equipment is needed to grow on this fixed pergola trellis, with manual cutting. This is currently only a small trial patch growing a trial variety of sultanatype fruit. There is no comparative data on this trellis system. Biannual cropping could be riskier. v