TECHNICAL
Forest Lodge Orchard’s AGI Frost Fan in the foreground and the western fan in the background
The future of frost fighting It’s the modern-era question – fossil fuels or electric futures? By Heather Woods Under crisp, Central Otago skies, co-owner Mike Casey and the team at Forest Lodge Orchard are on a mission – an electric mission. With a blank canvas, they’ve chosen electricity as their power-of-choice with the goal of farming without fossil fuels. Chris Kay, marketing manager at New Zealand Frost Fans, whose diesel-fuelled fans are making a noise in the crop management arena, explains the superior blade design and premium monitoring technology that sets them apart. The science of frost There are different types of frost including radiation frost and advection frost (the kind that comes from a polar blast). Radiation frosts are the most common type in New Zealand and Australia, characterised by clear, calm conditions with a temperature inversion and temperatures greater than 0°C during the day. And they can devastate entire crops and orchards if not managed in the right way. The sun warms the ground during the day, then after sunset the ground radiates that heat back out. As that heat rises above crop
62
The ORCHARDIST : AUGUST 2021
height, the colder, heavier air above moves in underneath, causing bud and flower damage. Frost fans like the FrostBoss and those from South Africabased AGI Frost Fans, pull the warmer air back down into the crops. And while there are no guarantees, it’s a great insurance policy for your crops, with one fan covering six to nine hectares. Crops that have an overhead canopy netting, like kiwifruit, benefit from around 5.5-hectare coverage. The benefits don’t stop at crop protection either, with vineyard and orchard owners seeing a reduction in overhead costs and crop management risk. Frost fans cost less than using helicopters, and with automatic start/stop at pre-set temperatures there is no need to make judgement calls on when you will actually need them. Many growers have moved to using frost fans instead of water sprinklers, which use large volumes of water, at considerable cost. There is also a risk of sprinklers freezing, and the mud created makes orchard maintenance and access harder.
