Sundial experiment – Nectarines

This experiment focuses on investigating productivity and quality of nectarines. Orchard productivity, yield and fruit quality are directly related to light interception and light distribution. In the Sundial orchard we have the opportunity to undertake a detailed study on light regimes on tree performance and fruit behaviour. Topics under investigation include fruit quality (size, colour, sweetness, maturity), yield, floral initiation (avoiding barrenness), photoinhibition and water use efficiency.

The midseason nectarine cultivar ‘Majestic Pearl’ was grafted onto Nemaguard rootstock and planted in Winter 2018 at 1.0 m tree spacing in five parallel rows at 3.5 m spacing in each of the four row orientations. Within each row orientation are four canopy architectures (Tatura Trellis, Vertical leader, and two V-cantilevers) provide diverse canopy foliage regimes in relation to the sun (light interception, light distribution).

Trees have been trained to their respective canopy architectures with laterals regularly stubbed during the first season to encourage the tree to reach its maximum height. Next season the focus will be on creating horizontal fruiting laterals coming off the main leader and the four 2-D canopy architectures. Observations of flower bud development and canopy size in relation to radiation will commence in the second season.

About the sundial experimental orchard

Agriculture Victoria is developing a new “Sundial” experimental orchard at its Horticulture SmartFarm research site in Tatura. The sundial experimental orchard was established and launched in 2018 and is a key component to the SmartFarm initiative, part of an integrated experimental orchard complex established at both the Tatura and Mildura research sites.

Technologies that will be utilised in the Sundial orchard include lidar, vision sensors, artificial neural networks, thermal, and near-infrared and multi-sensor fusion.  These will be deployed via satellite, UAVs, on-ground vehicles (potentially robot), handheld and permanently mounted on a rotating platform in the middle of the Sundial orchard. Additional technologies will include drainage flux sensors and displacement transducers to measure fruit and trunk growth, in-orchard RFID and NFC tree and fruit identification, IoT enable irrigation control and feedback sensors, and the use of laser technology to write on fruit to enable research precision, precision GPS (horizontal and vertical to identify fruit location) and further development of the electronic nose and the DA-meter.

The sundial orchard was prepared using best soil management practices and is irrigated using the latest technology (e.g. in-line drip emitters, row orientation and treatment-based management units, electronic flow meters and nutrient injection). Treatment effects and spatial and temporal variation in flowering behaviour, fruit set, marketable yield, and fruit size, colour, sweetness, firmness, sun damage (bleaching, sunburn), maturity and storage attributes will be measured. The sun dial orchard provides a facility to evaluate sensors (e.g. fruit maturity, water and nutrient status, pest and disease detection) and technologies (e.g. robotic harvester and pruner, variable rate spray for flower thinning and the application of pesticides).

The Sundial orchard evaluates the features needed to design future orchards.  The orchard provides four row orientations (N-S, W-E, NE-SW, NW-SE), vertical, cantilever and V architectures, and dwarf rootstocks.