Researchers at the 12th International Conference on Precision Agriculture demonstrated many applications of spatial management with potential relevance to Australia
Technologies such as guidance, autosteer and GPS land levelling have been described as just ‘the tip of the iceberg’ in terms of the potential that spatial management has to offer.
Sharing ideas on precision crop protection and disease management at the 12th International Conference on Precision Agriculture, (from left) Corne Kempenaar, the Netherlands, Victor Alchanati, Israel, Karl-Heinz Dammer, Germany, Sandra Gomez, Germany, and Anders Jonsson, Sweden.
PHOTO: Emma Leonard
However, delegates at the 12th International Conference on Precision Agriculture, held in California in July, found themselves asking where the potential new developments in spatial management would come from.
Some interesting possibilities with clear potential for Australian grains production were outlined by research teams from around the world, raising hopes among Australian researchers that this country’s prior leadership in precision agriculture (PA) research and on-farm application will pick up again.
The following applications were presented as examples of the next stage of PA-based research and applications.
The effectiveness of soil-applied herbicides is known to decrease with increasing clay and organic matter content. Researchers from Wageningen, the Netherlands, are using soil texture maps created from gamma-radiometric, electrometric and near-infrared data to vary rates of different herbicides in sugarbeets. In on-farm experiments herbicide rates were reduced by 15 per cent without reduced weed control.
While organic matter content is generally low in Australian soils, clay content can vary considerably. Could tailoring soil-applied herbicide rates to soil texture offer Australian growers another tool to improve weed control and fight resistance?
Potatoes are a major crop in the Netherlands and haulm-killing herbicides are used prior to harvest. Researchers have been experimenting with varying herbicide rate by biomass.
Crop biomass has been collected using ground-based (proximal) biomass sensors as well as sensors mounted on an unmanned aerial system (UAS) and from satellites. Varying inputs on-the-go and from a task map generated from previously gathered biomass data were both tested. Injection sprayers as well as section control sprayers were used for the application.
Following eight years of research with different sensor and sprayer combinations, the team established that, on average, herbicide application was reduced by 31 per cent when matched to biomass.
A large part of this work was the development of dosing algorithms to vary spray rates in relation to biomass. In Australian grain crops the application of desiccants in direct-headed canola and in the crop-topping of pulses could potentially benefit from a similar approach.
In Sweden, researchers have been experimenting with soil mapping clubroot rot in brassica crops. Using molecular-based soil tests for root disease, the team was able to rate whole paddocks for disease. Longer rotations out of brassica were able to be applied in paddocks with high disease ratings.
These tests are similar to those developed by the South Australian Research and Development Institute for soil-borne diseases such as crown rot, pythium, bipolaris root rot and cereal cyst nematodes. With more growers having the equipment to vary rates of seed and other inputs, should disease mapping in Australia be revisited?
Cotton root rot has been an ongoing problem for the US cotton industry. The recent registration of a fungicide to control the disease led researchers in Texas to look at the spatial distribution of the disease and the potential for patch application of the fungicide.
Analysis of airborne multispectral imagery, which included visible and near-infrared wavebands taken in 2001 and again in 2011 and 2013, identified that the spatial pattern of root rot was relatively stable. Consequently, it was calculated that only between 17 and 25 per cent of the 105-hectare paddock required fungicide treatment, depending on seasonal conditions.
Precision tools are becoming more widely used to support research, especially in plant breeding. Researchers at the University of Bonn in Germany have used thermal imagery for the early detection of downy mildew in rose cultivars. This was achieved with scans of the canopy and from the side of the plant row.
One German project was focused on developing real-time fungicide application rates for winter wheat. This work has highlighted the importance of sensing for leaf area index (LAI) and not purely biomass as the determinant of fungicide rate. An ultrasonic sensor is being used to measure LAI.
Local researchers say the adoption of spatial technology across all aspects of grains production offers opportunities to help Australian growers remain internationally competitive.
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