Electrical control of weeds

Credit: smallrobotcompany.com

Weed menace all around have been an age old phenomena but with changing climatic conditions, easy and frequent movability of people, use of imported seeds etc. have further helped in their (weeds) growth all over the regions. Growing presence of weeds not only in agriculture fields but in grass fields, forests and even in surroundings all over has already created a havoc on the people totally dependent on these segments for their daily livelihood.  With growing tendencies of people to avoid hard work as put by old generations to pull (mechanical extraction) all types of weeds manually at regular intervals, is further leading for the unwanted growth and over powering of agriculture produce, grass and forest lands by these weeds leading to great loss of resources.

People are looking for easy ways i.e., use of harmful chemicals to get rid of these weeds but such a use not only helps in the control of weeds but also creating a big loss of other natural resources like useful plants, animals, birds, micro-organisms and through a natural cycle from fields à water à gran à animals à human the use of dangerous chemicals are finally proving harmful towards the wellbeing of mankind itself. Thus, with the growing use of harmful chemicals to control weeds, we are losing many valuable natural resources and having adverse effect of wellbeing of all natural living beings.

Methodology

Electricity with its easy availability and user friendly nature has already become the lifeline of present civilization and we are totally dependent on the use of electricity in leading our day to day life activities. Now people are looking forward towards electric control of weeds also. Use of electricity to kill weeds is an old idea but the increasing concerns about chemical herbicides are giving a boost to the old idea of killing weeds with electricity.  The electric weed control systems used are of generally of two main types: i) spark discharges or shockwaves and ii) continuous contact. The spark discharge method uses high-voltage with short-duration pulses e.g., 25–60 kV& 1–3 μs, for weed control, plant thinning and the acceleration of ripening. The continuous contact method uses an electrode connected to a high-voltage source (e.g. 15 kV, 54kW) and as it touches the plants, current flows for the duration of the contact time. This second method is used for pruning and desiccation of root crop foliage, as well as weed control and row crop thinning. During the process, the plant tissue is damaged by current flow and the shockwave being generated due to the discharge in pulsed systems whereas, similar action towards weed control is achieved by the rapid heating effect of the electric currents in continuous contact devices.

Development status

Use of electricity boasts some key benefits over other non-chemical forms of weed control, which include using mechanical extraction, hot water, steam and chemical herbicides. In particular, electric weed control doesn’t require any water and also does not produce any environmental pollution. This method is also considerably more energy efficient than using steam, which requires an order of magnitude more fuel. And unlike mechanical means, electric weed killing is also consistent with modern “no till” agricultural practices and the cost is now comparable with chemical herbicides. Late in 19th century, American railroad companies struggled with the problem of growth of weeds all around railroads as across the world. The solution that railroad engineers devised made use of a then termed as a new technology making use of high-voltage electricity, which they discovered could kill troublesome vegetation overgrowing the railroad tracks. Later on, the people in charge of maintaining tracks turned to using fire instead of using electric control of weeds. Further, the approach to weed control by one and all was adopted to apply chemical herbicides, which were thought to easier to manage/use and were more effective. However, the idea of using electricity to kill weeds never really died from the horizons of weed control. At present, a U.S. company “Lasco” has been selling electric weed-killing equipment for decades now and more recently, another company has been marketing this technology under the name “The Weed Zapper.” But the most interesting developments towards electric killing/control of weeds have taken place in Europe, where electric weed control seems to be gaining real traction. One company trying to replace herbicides with electricity is Root Wave, based in the U.K. developed by a researcher at the University of Sheffield while studying ways to control weeds with electricity.

Unlike the electric weed-killing gear that’s long been used in the United States, a new version of electrically killing weeds known as “Root Wave” equipment runs attens of kilohertz-a much higher frequency than the power mains. This brings two advantages, i) it makes the equipment lighter, because the transformers required to raise the voltage to weed-zapping levels (thousands of volts) can be much smaller and ii) it also makes the equipment safer, because higher frequencies pose less of a threat of electrocution as the system operated at 50 or 60 hertz. Further, electrically killing weeds machines are coming in their various designs like hand-carried or tractor driven systems with further plans to outfit an agricultural robot for automated weed killing with electricity. An Israeli company Taran is, for example, uses computer vision, satellite and drone imagery to identify precisely what weeds are growing and where, allowing weed killer to be far more tightly targeted.  Such electrically controlled killing of weeds machines are being developed all over the world and similarly, Netherlands-based CNH Industrial is also promoting electric weed control with a tractor-mounted system called as “XPower.”  While using, the electrodes in the machine are swept over a field ata prescribed height, thus, killing the weeds that poke up higher than the crop to be preserved. The XPower system, which attaches to a tractor, kills plants in less than a second by pulsing electricity through them to destroy the vascular bundles that transport water and nutrients.

Conclusion

Taking into consideration the environmental pollution and harmful effects of the use of chemical control of weeds to living species involved directly or indirectly with the agriculture profession or depending on its produce, people are desperate for another way beyond chemicals to fight weeds and electricity is back on the agenda. Moreover, against a backdrop of agriculture’s ongoing herbicide resistance issues and pesticide litigation, the use of electricity as a feasible means of weed management in general is gaining grip as both old and new electric killing of weeds technologies capable of eliminating weeds attract attention.  Thus, controlled and safe use of electricity has come up as the most viable source of weed-control energy. Experimental systems have been developed for weed beet control (15 kV r.m.s., 50 kW) and these can treat infestation densities of up to 5000 stems/ha. Commercially, electrically killing weeds through continuous contact equipment have been developed in various countries for farm weed control, forest undergrowth clearance and railway track weed clearance. Electrical weed control is a versatile and rapid technology, and is cost competitive with chemical applications if used on more than 900 ha/a. In near future, weed-fighting machines wielding voltage will be a common feature beneath equipment shops and sheds and farmers/agriculturists of any level will be able to control weeds with electricity.

Further reading:

  1. Vigneault C., Benoît D.L. (2001) Electrical Weed Control: Theory and Applications. In: Vincent C., Panneton B., Fleurat-Lessard F. (eds) Physical Control Methods in Plant Protection. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-662-04584-8_12
  2. https://spectrum.ieee.org/tech-talk/energy/environment/the-electric-weed-zapper-renaissance
  3. https://www.bbc.com/news/business-50711566#:~:text=The%20XPower%20system%2C%20which%20attaches,that%20transport%20water%20and%20nutrients.
  4. https://www.agweb.com/article/old-sparky-could-electricity-be-farmings-new-weed-killer
  5. http://rootwave.com/

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