Mobile electron beam irradiation for precision weed control in row crops

Overview

This solution applies compact electron accelerator technology originally developed for radiation oncology to precision agriculture, specifically for postemergence weed control. By combining AI-driven weed identification with magnetic beam steering—similar to radiotherapy scanning techniques—the system delivers lethal megavoltage irradiation directly to weeds while keeping scatter dose to crops below growth-inhibition thresholds.

The approach addresses several critical challenges in modern agriculture. Herbicide resistance is a growing problem across major row crops, and this method provides a completely different mechanism of action that does not contribute to resistance development. Unlike chemical herbicides, irradiation leaves no environmental residue and may offer a more sustainable alternative for integrated weed management programs.

Target crops include corn, soybean, and sweet potato. Target weed species include yellow nutsedge, Palmer amaranth, entireleaf morningglory, sicklepod, and pink purslane—all major pests in southeastern U.S. cropping systems.

Technical specifications

System components:

• Compact 6 MeV electron accelerator operating at approximately 50 kW, delivering a dose rate of roughly 1.25 kGy per second per square meter
• AI-based weed identification adapted from existing see-and-spray robotic platforms to recognize and locate target weed species in real time
• Magnetic beam steering that directs the electron beam to identified weed locations, analogous to radiotherapy beam scanning
• Monte Carlo dose modeling (MCNP6) to predict scatter dose distribution and confirm crop safety thresholds

Performance estimates:

• Yellow nutsedge tuber control achieved at 1–1.5 kGy in preliminary pot trials
• Estimated treatment time of approximately 8 minutes per acre when weeds cover 10% of the field, using a single accelerator unit
• Treatment throughput is scalable by deploying multiple accelerator units in parallel

Validation design:

• Greenhouse-grown weeds and crops at NCSU irradiated at Duke Radiation Oncology using a clinical Varian linear accelerator at 6 MeV
• Five dose levels with six replications; crops treated at three growth stages
• Weekly growth measurements over four weeks post-treatment

Technology readiness level

The concept is at an early-to-mid stage of development. Preliminary validation has demonstrated effective control of yellow nutsedge tubers at doses that are feasible for a mobile compact accelerator. Future greenhouse trials at NCSU and Duke will quantify crop tolerance and weed efficacy across multiple species and growth stages, while Monte Carlo simulations will characterize scatter dose for the proposed compact accelerator geometry. Additional engineering work is needed to integrate AI-guided targeting, magnetic steering, and accelerator mobility into a field-deployable platform.