A Concept of a Compact and Inexpensive Device for Controlling Weeds with Laser Beams

Ildar Rakhmatulin,Christian Andreasen

doi:10.2139/ssrn.3716607

Abstract

A prototype of a relatively cheap laser-based weeding device was developed and tested on couch grass (Elytrigia repens (L.) Desv. ex Nevski) mixed with tomatoes. Three types of laser were used (0.3 W, 1 W, and 5 W). A neural network was trained to identify the weed plants, and a laser guidance system estimated the coordinates of the weed. An algorithm was developed to estimate the energy necessary to harm the weed plants. We also developed a decision model for the weed control device. The energy required to damage a plant depended on the diameter of the plant which was related to plant length. The 1 W laser was not sufficient to eliminate all weed plants and required too long exposure time. The 5 W laser was more efficient but also harmed the crop if the laser beam became split into two during the weeding process. There were several challenges with the device, which needs to be improved upon. In particular, the time of exposure needs to be reduced significantly. Still, the research showed that it is possible to develop a concept for laser weeding using relatively cheap equipment, which can work in complicated situations where weeds and crop are mixed.

Highlights

Weeds are one of the most significant yield-reducing factors for crop production worldwide [1].Herbicides have been widely used with great success since 1950s, but today, herbicide-resistant weeds are becoming an increasing problem in agriculture [2]
The detection accuracy of E. repens depends on the number of datasets and how well the datasets reflect the real conditions
A laser weeding system based on rather cheap equipment was created

Summary

Introduction

Herbicides have been widely used with great success since 1950s, but today, herbicide-resistant weeds are becoming an increasing problem in agriculture [2]. The possibilities of developing new effective herbicides, which can meet the environmental and safety requirements of today, seemed to be exhausted, as no new mode of action of herbicides has been developed since the 1980s [5]. This situation, together with the increasing public interest in organic food [6], calls for integrated weed management approaches to reduce weed problems in the future. Soil tillage has disadvantaged as it increases the risk of soil erosion and leaching of plant nutrients, dries out soils with limited water content, and harms beneficial soil organisms like earthworms

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