Symposium unveils the latest in PA

The diversity of the GRDC's investments in precision technology was on display at teh 16th Symposium on Precision Agriculture in Australasia.

Photo of Hermann Leithold

Hermann Leithold was international keynote speaker at the 16th Symposium on Precision Agriculture in Australasia. His family's company, Agri Con, is about to commercialise the world's first weed identification camera that can distinguish between crops and weed types.

PHOTO: Emma Leonard

“Precision agriculture (PA) is well placed to provide solutions to feeding an expanding population in a resource-limited environment.”

This comment by Dr Brett Whelan, from the Precision Agriculture Laboratory (PA Lab) at the University of Sydney, in his welcoming address was reflected often in presentations at the recent 16th Symposium on Precision Agriculture in Australasia, held in Perth.

Speakers shared their research on the very practical, such as how to successfully use PA technology to set up and harvest on-farm trials, as well as using high-tech autonomous equipment and developmental microspectrometers. Many projects presented were supported by the GRDC.

Precision applications were also presented for horticulture, livestock management and viticulture, as well as for the grains industry.

Brooke Sauer, Precision Cropping Technologies, launched the PA Help Desk (, an online resource that provides a portal for all things relating to PA – including research and development, how-to guides and contacts for service providers.

Luke Dawson, from CSBP, reported on work with the Liebe Group that has shown an economic benefit from zoning paddocks by potential yield and managing inputs accordingly. In this trial the high, medium and low zones were created using multiple years of biomass imagery gathered around peak biomass and ground-truthed against soil samples and grower knowledge.

Matthew Roesner, Roesner Pty Ltd, and researchers from CSIRO looked at variable-rate fertiliser from the perspective of the cost of uneven fertiliser distribution. In many cases the distance between centrelines of successive spreader passes was found to have less impact on the predicted net income than the plant-available water capacity of the soil or the season.

On-the-go soil sampling for nutrients and variable-rate herbicide applications have been two PA technologies that have been missing, although Professor Dilusha Silva from the University of Western Australia reported that he and colleagues were making progress with revolutionary microspectrometers for soil and crop monitoring.

However, it was keynote speaker Hermann Leithold’s presentation on the H-sensor that was of particular interest to grain growers. Mr Leithold manages the plant protection division of his family’s business Agri Con in Germany.

Mr Leithold’s trip to Australia was supported by the GRDC. The invitation was extended to Agri Con as it is scheduled to commercialise the first weed identification camera, the H-sensor, in the next year.

The ‘H’ stands for herbicide and this sensor aims to reduce and target herbicide inputs. The sensor is able to distinguish between crops, grass and broadleaf weeds. For example, in cereal crop trials the sensor accurately identified blackgrass, which is similar to annual ryegrass, between 80 and 90 per cent of the time. In another example, the sensor could reduce herbicide inputs by 35 per cent as broadleaf weeds were correctly found not to be present in 28 per cent of a crop of millet.

These results were based on the use of four sensors, located on each section of a sprayboom. The camera triggers each section of the boom to be switched on or off depending on the presence of detected weeds.

“The objective is not to identify every weed but patches of weeds, so that boom sections can be switched off when herbicide is not required,” Mr Leithold says.

“New weed types can be easily added to the identification software.”

The cameras are normally mounted on an arm 75 centimetres in front of the boom. This distance allows a travel speed of up to 12 kilometres per hour. Extending the arm allows higher travel speeds.

Weeds have been successfully sensed in a range of crops to the point of canopy closure. Mr Leithold says the system is not influenced by stubble, rocks or soil. The plan now is to test the H-sensor in Australian conditions and with Australian weeds.

The symposium illustrated how exploration of overseas technical solutions can be a cost-effective investment for the Australian grains industry. Examples presented at the symposium included an on-the-go soil tester developed by the Tokyo University of Agriculture and Technology. Using near-infrared technology, this machine measures and maps the underground reflectance of 19 soil parameters including the key macro and micronutrients.

Another was a hand-held fluorescence meter, developed in France. This is able to measure nitrogen and abiotic stress levels in plant leaves and has been used in the early detection of leaf fungal diseases in grapevines.

Two new PA-related publications were presented at the symposium. Precision Agriculture for Grain Production Systems, from the PA Lab, is based on years of GRDC-supported research. It is available as hard copy or as an ebook from CSIRO Publishing. A second title, Applying PA – a reference guide for the modern practitioner, will be available from Ground Cover Direct.

The symposium was run by SPAA-Precision Agriculture Australia and the PA Lab. 

More information:

Dr Brett Whelan,
02 8627 1132,;

Dr Nicole Dimos, SPAA-Precision Agriculture Australia,
0437 422 000,


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