By Ian Goodwin and Alessio Scalisi Agriculture Victoria

Protecting orchard crops from hail, rain and excessive sunlight is becoming increasingly important to avoid fruit damage.

Hail and extreme heat events appear to be more common as our climate is changing and rain spoilage is an ongoing issue in stone fruit crops, particularly cherry. 

One of the components of the project ‘Growing horticulture through protected cropping innovation’ is to study netting, rain cover and agrivoltaics in fruit orchards.

To undertake this work, a combination of demonstration, experimental and commercial orchards will be used.

Environmental conditions will be monitored under demonstrations of autonomous retractable netting and rain covers at the Tatura SmartFarm in northern Victoria.

Light transmission characteristics of different netting types and colours will be investigated in established commercial orchards as well as under new netting systems at the SmartFarm.

Long-term effects of solar panels above pear trees will also be measured, and the latest horticulture solar technology in Australia and overseas will be explored.

A demonstration of auto-retractable rain covers will be set up above a new cherry orchard and this demonstration will use a rain sensor and smart programming to alert and trigger the closure and opening of the rain cover.

Air temperature and relative humidity under the auto-retractable rain cover will be compared to a rain cover system in an adjoining new block that is manually deployed after fruit set and retracted after harvest.

Similarly, a mechanical retractable netting system (Valente Wayki) is being set up above a new block of apple at Tatura.

The mechanical system is amenable to sensor driven automation through sunburn risk and hail forecasts.

Sunburn risk will be determined by estimates of fruit surface temperature from weather data (radiation, temperature, relative humidity and wind speed) and fruit size.

The project will explore the risk of approaching hailstorms using radar.

Netting is available in many weave densities and colours, and each has specific light transmission properties which can influence yield and fruit quality.

A multispectral radiometer will be used to measure netting light transmission broken down into 2nm increments from ultraviolet through the visible spectrum to infrared wavelengths that impact on fruit sunburn, colour development, flower initiation and photosynthesis.

Measuring long-term effects of shading from solar panels in the existing agrivoltaics experiment at the Tatura SmartFarm is another activity in this project.

The experiment was established to study the effects of solar panels above pear trees and demonstrate solar energy generation, storage, utilisation and export in orchards.

Initial results have shown benefits to the crop (no sun damage and a reduction in hail damage) but also indicated losses in fruit colour and size.

However, results need to be confirmed and the effects on floral initiation determined.

The project will also review more recent national and international advances in solar technology (e.g., manoeuvrable panels, photo-selective cells, light weight and flexible material, integrated solar and netting designs).