Sensor-based mechanical weed control: Present state and prospects

Mechanical weed control in agriculture has advanced in terms of precision and working rate over the past years. The real-time communication of implements with sensor systems further increased the potential of mechanical weeding. There is a wide array of available sensors including image analysis by camera, GNSS, laser and ultrasonic systems that can improve weed control efficacy in combination with mechanical systems. Every sensor type has its advantages and disadvantages. Camera-steered hoes with a hydraulic side shifting control for row crops are robust and reliable and they are now widely available from different manufacturers. The robotic sector has difficulties handling the everchanging environment of agricultural fields and fully automated systems may not exist for many years. This review looks at the developments in sensor-based mechanical weeding since the 1980s. It focused on scientific studies presenting data results of their work, with the aim of providing an overview of the possibilities of sensor-based systems and to show their efficacy. The practical application for current and future farms is considered and discussed. Furthermore, an outlook towards sensor-based mechanical weeding in the future and necessary improvements are given.