Laser Weeding With Small Autonomous Vehicles: Friends or Foes?

Abstract

Weed control is necessary to ensure a high crop yield with good quality. Herbicide application and mechanical weeding are the most common methods worldwide. The use of herbicides has led to the increasing occurrence of herbicide-resistant weeds and unwanted contamination of the environment. Mechanical weed control harms beneficial organisms, increases the degradation of organic matter, may dry out the soil, and stimulate new cohorts of weed seeds to germinate. Therefore, there is a need to develop more sustainable weed control means. We suggest using small autonomous vehicles equipped with lasers as a sustainable alternative method. Laser beams are based on electricity, which can be produced from non-fossil fuels. Deep learning methods can be used to locate and identify weed and crop plants for targeting and delivery of laser energy with robotic actuators. Given the targeted nature of laser beams, the area exposed for weed control can be reduced substantially compared to commonly used weed control methods. Therefore, the risk of affecting non-target organisms is minimized, and the soil will be kept untouched in the field, avoiding triggering weed seeds to germinate. Small autonomous vehicles may have limited weeding capacity, and precautions need to be taken as reflections from the laser beam can be harmful to humans and animals. In this paper, we discuss the pros and cons of replacing or supplementing common used weed control methods with laser weeding. The ability to use laser weeding technology is relatively new and not yet widely practiced or commercially available. Therefore, we do not discuss and compare the costs of the various methods at this early stage of the development of the technology.

Weed Management in Pulses: Overview and Prospects

“…Andreasen et al [46] highlighted that Autonomous Laser Weeding is a cuttingedge technique for weed management that is a prototype, not yet widely used or sold commercially. Artificial intelligence and deep learning are being deployed to precisely locate and distinguish weeds [47,48] and burn the meristems of the targets with laser beams released by robotic actuators for real-time weed control.…”

Laser weeding: opportunities and challenges for couch grass (Elymus repens (L.) Gould) control

“…Consequently, exposing several meristems for the laser beam may be necessary, which complicates and slows down the weeding process. Therefore, laser weeding of weed seedlings should be done when weeds are at the early developmental stages 19 , 20 .…”

“…A thulium-doped 2 µm fibre laser has been installed in the autonomous vehicle for laser weeding developed in the EU project WeLASER ( https://welaser-project.eu/ ). A laser energy dose below 20 J mm −2 may be used to control small weed plants in crop fields 15 , 18 , 19 . We hypothesized that depending on plant size, it would be possible to kill and prevent regrowth from small belowground parts after two laser treatments.…”

Evaluation of Diode Laser Treatments to Manage Weeds in Row Crops

“…Targeted narrow laser beams have the potential of removing not only the inter-row weeds but also the intra-rows weeds with proper detection, localization and laser targeting hardware and software. In addition, effects on soil health and non-targeted organisms will be minimized, avoiding interference with other crop activities, and preserving beneficial organisms [28].…”

“…Furthermore, looking at laser safety, the laser beam turns into heat energy when it hits a surface. High energy lasers can potentially ignite materials and can cause thermal injury to a person [28]. Using diode lasers of low output power present less operational danger than the high-powered and more complicated CO 2 and fiber lasers; however, it can still cause damage to the eyes on exposure, so, proper caution wearing protecting glasses is necessary [28].…”