Assessing the Viability of Fresnel Lenses for Weed Control in Prickly Pear Cactus Cultivation: A Spatiotemporal Coverage Perspective

TL;DR

This paper explores the use of linear Fresnel lenses integrated into autonomous ground vehicles for sustainable, precision weed control in prickly pear cactus cultivation, emphasizing spatiotemporal coverage and solar-based thermal weed management.

Contribution

It demonstrates the technical feasibility of a novel autonomous system using Fresnel lenses for targeted thermal weed control, combining real-time imaging and georeferencing.

Findings

Viable for sparse weed infestations

Effective during peak solar irradiance

Suitable for precision agriculture in tropical regions

Abstract

In tropical semiarid regions, prickly pear cactus has emerged as a vital forage resource due to its high drought tolerance and minimal water requirements. However, even limited weed infestation can severely compromise cactus productivity, as the species are highly sensitive to competition for essential resources, which includes water, mineral nutrients, and sun exposure. Conventional herbicide-based weed control strategies face growing limitations due to resistance development and environmental concerns, underscoring the need for sustainable alternatives. This study revisits the historically underexplored application of linear Fresnel lenses for thermal weed control and establishes the technical feasibility of a contemporary autonomous weed management system that incorporates LFL technology within an unmanned ground vehicle platform. Leveraging real-time image processing, georeferencing, and mechanical actuation, the system can perform a two-phase operation-weed mapping during non-optimal solar hours and targeted solar termination during peak irradiance. Analytical modeling quantifies the effective area coverage and time constraints imposed by the solar window. Preliminary results indicate that, while unsuitable for dense weed infestations, the system presents a viable solution for precision, post-emergent weed control in sparse infestations. The favorable solar geometry in tropical zones, especially in the Brazilian semiarid region, and the targeted nature of the approach make this technology particularly well-suited for sustainable agriculture in under-resourced regions.