Electric weed control was an effective weed management strategy. Control of broad leaf weeds was easier than grass weeds at higher operation speed. However, at the recommended speed, control of grass weeds was as effective as herbicide application even in the viticulture production system that contained mature, dense, wet plants (and wet topsoil), and where control should have been poor. There is an industry based ‘understanding’ that electric weed control would be less effective when surface soil moisture was high, and this was confirmed in 2023 when treating mature, dense annual ryegrass at 2 km h-1. However, our research demonstrated that weed control in moist soils can be achieved with appropriate application speeds.

The level of control varies between weed species, as for any weed control technique. Plant age reduces control, as does high plant density or the tendency of plants to shade and protect smaller plants. For some species, electric weed control is superior to herbicide. For example, while both electric weed control and herbicide caused senescence of the above ground biomass of cape tulip plants, double applications of electric weed control were more likely to prevent growth of the bulbs in the subsequent year. More research is required to test electric weed control against a wider range of species, but this weed control technique is more versatile than most individual herbicides.

Electric weed control was successful at reducing weed biomass without affecting the soil biota. The soil microbiome was not affected by electric weed control in the viticulture trials or the trial on rhizoctonia. While the DNA sequencing used in the viticulture trials cannot categorically rule out damage to the soil microbiome (as the method can sequence both dead and live DNA), there was no change to the microbiome between sampling times. It is highly unlikely that no change would be observed between sampling times if the microbiome had been affected by weed control treatments. There was little direct impact on nematodes, although reduction in weed and root biomass can affect nematode populations in the long term. Rhizoctonia, which is physically attached to the weed roots, was not damaged by very slow and repeat application of electric weed control. No damage to the soil microbiome is good news for organic growers, such as in the viticulture industry.

This technology is not designed for inter-row weed control in broad acre crops, but our research has demonstrated that inter-row electric weed control does not damage the crop in the neighbouring rows. We trialled electric inter-row weed control in conditions designed to maximise crop damage, when the crop growth stage was at anthesis, and the surface soil was moist. Inter-row electric weed control applied to younger plants, with technology specifically designed for this use pattern, is likely to be a highly safe and effective form of in-crop weed control. However, further assessment with technology specifically designed for inter-row weed control is required to confirm these findings.

Fire risk from the machine was not evident in winter and spring. Fire risk when operating in completely dry residue (i.e., in summer or autumn) was much too high to allow use in these seasons in southern Australia as assessed in experimental conditions and on a viticulture estate.

Assessing the power applied during each experiment indicated that power varied due to weed presence (i.e., compared to bare ground). Further, weed density and speed of operation has been identified as valuable to examine. In 2023, analysis is occurring to determine the effect of weed biomass on the power output and fuel consumption of the machine. Analysis will also determine if this technology can be used to create a ‘map’ of weed incidence for future application in precision agricultural systems. However, further data manipulation is required before the analysis can be completed.

Applying electric weed control with the XPower with XPU applicator at 2 km h-1 had a high application cost of $210.55 ha-1 with 10.48 L h-1 of diesel used. While such applications may not be cost effective, they may be justified in certain situations where the value of controlling the weeds outweighs the cost of electric weed control. For example, when herbicide resistance is high, near waterways or irrigation channels where chemical use is restricted, or for organic growers. Alternatively, there may also be scope to combine the technology into fully automated agricultural systems which would reduce the application cost by over half to $85.55 ha-1.

While research is ongoing, this project has demonstrated thus far that the XPS unit is a viable tool for spring weed control in Australian viticulture/horticulture and will find an immediate fit into these systems. Likewise, the XPU will contribute effectively to urban and industrial weed control in Australia.