With a total annual turnover of approximately 500 million euros, the Netherlands is a major player in the production, import and export of fruits. In spring, when the night temperature drops below freezing point and fruit trees are flowering, fruit growers must protect their crops. If the flower buds were to freeze then no fruit is formed, resulting in enormous economic losses. Protecting the buds is usually done with the help of water, which requires an average of 30 m3 of water per hectare per hour. If several nights of frost occur the limit on water availability can be reached quickly. Moreover, if the quality of the water is not sufficient (e.g. due to salinity), the water can also cause damage to the crops. As a result, about 30% of the fruit companies in the Netherlands cannot use water for frost protection.

As an alternative to using water, wind machines to protect fruit trees against frost is emerging as a promising new and innovative technique. The propeller of the wind machine mixes the cold air with the higher, warmer air and can thus raise the temperature on the ground by several degrees. This feasibility project explores the opportunities of an innovation project for monitoring the effectiveness of wind machines for frost protection in fruit cultivation using flying sensors (drones) equipped with a thermal thermal imager. The results of this feasibility project may lead to an innovative information service intended for fruit growers to:

1. Provide insight into the effectiveness of wind machines for frost protection as a cost-effective and sustainable alternative to spraying water. This service can target growers who already use wind machines and want to know how effective wind machines provide protection against night frost, but also growers who are considering wind machines and want to know to what extent the application can be suitable for their field.
2. Advise how the application of wind machines can be optimized in the business operations of fruit companies. This includes optimal placement of the wind machine in the orchard and whether the wind machine is properly adjusted for the type of fruit being grown. This relies on what rotational speeds are needed for a given temperature increase, at what angle the propeller should be aimed, etc.)

A prototype of this service will be developed and demonstrated for a pilot area through a development process. An important part of the development trajectory is research into and development of a:

1. State-of-art interactive visualization tool to visualize spatial information within a
2. (beta) web application such as a dashboard to offer the innovative information service to the end user (fruit grower).

The power of flying sensors with thermal imaging cameras is that the temperature-increasing effect of wind machines can be measured very precisely and can also be mapped spatially. This visual information can provide the fruit grower with insight and confidence that wind machines are effective for frost protection.

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• 2021 - FutureWater Report 231Cárdenas Niño, N., C. Nolet. 2021. Haalbaarheidsonderzoek: voorkomen van vorstschade in fruitteelt door flying sensors. FutureWater Report 231X

  MIT Haalbaarheidsonderzoek: voorkomen van vorstschade in fruitteelt door flying sensors

  Cárdenas Niño, N., C. Nolet