Mixing drones and hail nets

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Driving past an apple orchard today, you would be forgiven for wondering why many seem to be hidden under a canopy of fabric – and the answer is hail netting! It’s increasingly more common to find growers in many parts of the world using hail nets as a standard part of their infrastructure to protect against hail and severe weather conditions.

But that’s not all; nowadays, not only are nets being used to protect the trees against harsh weather conditions but also to protect against other environmental factors such as excess sunlight and pest damage, all the while improving tree health and enhancing fruit quality.  

Researchers (Dr. Lee Kalcsits and Dr. Stefano Musacchi, 2016) have determined that covering apple orchards with hail nets is an effective strategy in reducing the surface temperature of the fruit and the amount of UV radiation they receive. With climate change and the knock-on effects on fruit production being at the forefront of many growers’ minds, they are increasingly deploying netting to reduce the risk of sunburn and improve the flavour profile of their apples. This of course translates directly to the yield of ‘Class I fruit’ and consumer desirability of apples. 

Both hail and sunburn are present in a lot of fruit-growing regions, and hail nets have become a way to control both. However in an industry where margins are notoriously tight, it is an expensive undertaking that requires careful planning and consideration. For example, in orchards that get a lot of direct light, nets are effective at dispersing the light through the canopy, which actually allows more light into parts of the trees that would normally not see as much. In contrast however, growers in low-light environments need to consider the cost of potential harm of creating too much shade, this is where types of hail net structure, shade factor and variety grown need to come into consideration. 

Traditionally hail nets are supplied in black, white and grey; though we are increasingly seeing red, blue and green options on the market – colours which are supposed to enhance photosynthesis, yield and fruit colouration. To fully assess what netting is right for an orchard, it is important to work with specialists in the field to determine the colour, thickness and structure for your needs.

During initial engagement, one of the first things interested growers ask of Outfield is ‘will the system be able to work with hail nets, how can the drone see clearly?’ Fortunately it can! We have flown many hail net covered orchards and will fly many more. Dark coloured hail nets, especially black nets have very little impact on Outfield orchard surveys. The drone flies above the top of the nets looking in, and the dark coloured nets are easy for the camera to peer through. Lighter coloured nets do present a little more of a challenge, we need to ensure that the drone is oriented correctly to both the net and the sun so that there is no glare from the netting that could interfere with the imagery.

So growers that use hail nets can rest assured: you can enjoy all the protection that netting provides as well as all the benefits that Outfield provides.