Karina Griffin and Leoni Kojetin*

With the development of technology to remotely monitor a range of factors such as nutrients, soil moisture and weather status, a growing number of farmers are adding this capability to their orchard management.

Amongst the most popular equipment being installed is the on-farm weather station, the advantages of which were described by Gwendolyn Garrad in the June-July edition of Australian Tree Crop (pp48–49).

To ensure you reap the benefits of your on-farm weather station, it is critical to understand how each of the sensors work and what influences the accuracy of readings.

What to consider when choosing weather stations

Before buying a weather station, consider your situation, what data you want to collect and how best to collect it. Some key considerations are as follows:

- If buying online, check compatibility and user support for Australia, e.g. wireless or mobile network access, and if units from the northern hemisphere need to be recalibrated. Check if there is technical support and spare parts for the station here in Australia

- Check how you access data and how it’s downloaded. Most modern units have apps and/or a website, many of which come with subscription costs

- Decide whether corded, wireless or a combination best suits your site. This is particularly important for auxiliary monitoring devices like soil moisture probes. While wireless devices are convenient, they are often solar powered, which can be an issue in tree crops as you must install tall poles along the row to compensate for shading

- If connecting to auxiliary devices, e.g. soil probes, frost fans or irrigation solenoids, check that they are compatible with the weather station. Find out if they talk to each other directly or through specialised software and whether there are hidden subscription costs and/or relay devices required

- While a lot of Australian growers use Delta T for determining if conditions are appropriate for spraying, many countries don’t, so it’s generally not a standard data output. For example, Davis weather stations are common in Australia, but they are produced by an American company. While the Davis WeatherLink platform does not currently include a Delta T reading, the data feeds into several third-party applications that approximate Delta T.

Position and factors that influence measurements to get the most accurate data

Your weather station should come with a technical support service to provide correct positioning recommendations**. It is important to be aware that there is conflicting information between different companies selling the same units, and even in user manuals. The following table summarises key factors that tree crop growers should consider when placing a weather station on the farm.

** An exception to the rule is for anemometers and wind vanes mounted in a high position for the measurement of evapotranspiration. This combines factors of soil and plant surface evaporation, plant transpiration and wind speed for application in water management. Anemometers for this purpose should be placed about 2m above ground.

Some user manuals use vegetable or broadacre cropping as a guide in their anemometer placement recommendations and the focus is on collecting data for evapotranspiration readings.

In tree crops, we rely on wind speed and direction when spraying and in our records. If your anemometer and wind vane are located lower than the height you are spraying at, readings will be inaccurate. This is important because if a complaint is made and you are investigated, you will not be able to rely on the readings to prove you were doing the right thing. This could result in you being fined.

Never install a weather station on a shed as the data will not be accurate. There are multiple reasons for this; the rain bucket will be too high and affected by wind, and the radiant heat from the shed will render sensor readings like temperature and relative humidity useless and the shed roof could alter wind currents.

Maintenance and critter control

It is important to regularly check and clean your weather station to ensure data accuracy. Station manufacturers specify schedules for full maintenance but having a quick look once every one or two weeks is a good practice, particularly for automated rain gauges that can easily get clogged with debris and dust.

Ants can get into even the smallest gaps, and weather stations, sensors and hollow poles provide perfect homes. Put caps on poles and place ant deterrents or baits inside weather station components. Insecticide impregnated cattle tags and camphor products can deter ants from nesting.

Loose, hanging cords can get in the way of machinery and be a trip hazard. They are also enticing for curious birds to play with, and one researcher recalled seeing cockatoos cut right through cables with their beaks.

Spending more time at the installation phase to think through functionality will save you time down the track and prevent equipment malfunctions.

As with many things you get what you pay for. If you pick up a cheap weather station while getting a sausage at your local hardware store you will likely be disappointed with the accuracy and reliability. Take the time to do your homework and find a system that matches your technology skills and delivers the critical weather data you need to make timely on-farm decisions.

This article is part of the project: ‘Accelerating the adoption of real time localised microclimate monitoring in macadamia orchards and digital data for decision making project’ which was funded by the Queensland governments Agribusiness digital solutions grant program 2021–22

*Karina Griffin is a project support officer and Leoni Kojetin is the industry development manager at the Australian Macadamia Society. Email: weather@macadamias.org