Power Equipment Australasia

Miranda Slaven explained that electric weed control could be part of an integrated solution to reduce dependence on chemical inputs and create more sustainable farming systems. “Finding alternative weed control strategies to chemical measures is important in Australia, due to increasing rates of herbicide resistance and increasingly discerning market demands,” she said. “This new equipment is at the frontier of agricultural technology, and it is valuable to test it under Australian growing conditions to examine its potential application as a non-chemical methodology in our agronomic systems.” The equipment will initially be tested on its ability to control weeds onViticulture and horticulture properties, and later along roadsides and fencelines, as well as its use for fallow weed control at the department’s research facilities in the Grainbelt. The research will target herbicide-resistant weeds such as annual ryegrass and wild radish, and problematic agricultural weeds, including feathertop Rhodes grass and fleabane, as well as perennial weeds, including kikuyu and wireweed. Theprojecthas support fromtheGrainsResearchandDevelopment Corporation; Wine Australia, WA; consultants AHA Viticulture; and the Cotton Research andDevelopment Corporation. EQUIPMENT USED Peter Thompson, AGXTEND Product Manager, says the electro weeding equipment being trialled in Australia includes XPower units for Urban application (the XPU) and the XPower for Viticulture (the XPS). The XPU, Peter explains, is targeted at urban environments such as council roadsides, bike tracks, etc, while the XPS is built to manage under-vine weeds in Viticulture. The XPS features a laterally pivoting applicator head that swings back upon contact with the base of the trunk or stem. There is also a configuration (the XPO) for under-tree weed management in orchards, though XPO units will not feature in theAustralian trial. “We haven’t brought in theXPOat this point in the trial, but initially Viticulture, Orchards and the Urban/Councils would be the focus markets to begin,” Peter says. “There are two models available when it comes to the actual power supplies. The 24kW, typically used for the Viticulture and Orchards, and 36kWtypically used on theUrban applicator. Both aremounted on the rear 3-point linkage and driven via PTO of the tractor. We recommend a minimumof 110hp to operate the 36kWunit.” HOW IT WORKS The concept of the XPower is to create an electrical circuit through the plant, from the biomass above the ground through the roots and back. It is recommended for best results to operate with low top-soil moisture and a medium-to-high subsoil moisture level. As water is conductive, a high level of moisture on the surface will result in the voltage passing back the other electrodes above the root system, limiting the effect to the root systemof the plant. The physical characteristics of different kinds of weeds, unsurprisingly, will influence the behaviour of the electro weeding treatment. “Much like chemical application, there are limitations and/or different approaches taken depending on the weed type,” Peter says. “A broad leaf weed will have a larger surface area, thus conducting more voltage through the plant versus a grass-like weed. The root system will also be a factor; a dense root system means voltage is going to be distributed over a greater area compared to a tap root-type weed, where voltage is concentrated down to the central point.” Like any method of weed control, conditions such as plant maturity and density will also affect themanagement approach. For a ‘woody’ weed, the best approach would be to remove as much of the biomass of the weed as possible above-ground initially, and then treat the young regrowth with the XPower unit. “By doing this, the mature part of the weed, which has high lignin content, is removed – the higher the lignin content, the less conductive theweedbecomes,” Peter says. “It also removes a lot of the biomass above the ground, allowing the voltage to conduct through the new growth of the weed down into the root system, creating more effective results.” EFFECTS ON SOIL An important aspect of the trial will be the effect of electro weeding on soil. Trial project lead, research scientist Catherine Borger, says a literature reviewand reports fromEurope suggest soil health and soil biota are not compromised by the technology. “Our research will include an analysis of the technology’s effect on soil health, including soil microbial density and diversity, as well as soil root pathogens, such as rhizoctonia,” Catherine says. Meantime, Peter adds that “Studies to date showno harmto the soil environment or other roots.” FIRE RISKS Another vital feature of the research will be testing to ascertain the potential for the equipment to cause fires. “Due to the high voltage used there is the likelihood of arcing to occur,” Peter admits. “Because of this, it is recommended not to operate in environments with possible hazards such as built-up residue/fuel in dry conditions. If planning to adopt XPower weed control, other management practices need to be taken into consideration to manage these risks. However, the risk in the Urban environment and Viticulture settings targeting winter weeds is low.” MAINTENANCE & COSTS Very little maintenance is required to maintain the equipment. Electrodes are typically replaced annually on the XPS, and up to three times a year on the XPU, given that it tends to work on more abrasive surfaces. “It’s a very simple process to change the actual electrodes,” Peter explains. “For safety, it is recommended the units be inspected annually by a qualified technician.” Prices differ depending on the applicator and size of the Power Supply unit. Currently, a typical XPS setup is approximately 110,000€ (AUD$165,000) and the XPU135,000€ (AUD$200,000). The XPower XPS electro weeding unit is designed for applications in Viticulture. JULY - AUGUST 2022 | POWER EQUIPMENT AUSTRALASIA | 13

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