Browsing by Person "Alagbo, Oyebanji Olubunmi"

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Development and testing of new robotic weeding techniques for ridge and flat tillage systems
(2024) Alagbo, Oyebanji Olubunmi; Gerhards, Roland
Under changing climate, conservative tillage practice is expected to gain more popularity over conventional tillage in terms of reduced energy emission and drought resilience. Hence, a need to develop cheap-climate-smart farming solutions for the future. The results of four different studies are summarized below. The first review article summarized different forms of ridge tillage and their impact on crop yield, weed seedbank dynamics, and weed management. Due to improved soil structure and optimal soil moisture conditions provided by ridges, several studies have proven that ridges can accelerate crop emergence, thus stimulating early-stage competitiveness of crops against weeds. More importantly, re-compacted ridges may give more benefits in the long term. The study further emphasized the use of RTK-GNSS (real-time kinematic global satellite navigation systems) ridging system for pilot hoeing, spraying, and seeding – as a cheap alternative to automatic vision control weeding systems in flat seedbeds. In the second article, an autosteered living mulch seeder and hoeing prototypes (using RTK-GNSS-created ridges as a guide) were developed and tested. The impact of ridge re-compaction on soil physical properties was also evaluated. In the two-year field experiment, the combined hoeing and living mulch seeding prototypes attained 70 – 80% weed control efficacy (WCE) with no record of crop losses. This result was comparable to similar treatment in flat seedbeds. Temperature and soil moisture in re-compacted ridges were partly better than in flat seedbeds, whereas, root penetration significantly improved on ridges (40% higher) with relative gain in root biomass (ca. 53.6 g m-2) compared to flat seedbeds. The third study evaluated the performance of different autonomous hoeing combinations on re-compacted ridges. It was hypothesized that autonomous weeding methods using RTK-GNSS-created ridges can substitute broadcast herbicide and manual weeding in future farms. Six field trials were conducted including maize and soybean. The treatment options include; i). twice hoeing combined with band herbicide application on ridge tops, ii). twice hoeing, iii). twice hoeing combined with living mulch, iv). twice hoeing combined with post-emergent harrowing on ridge tops. All hoeing treatments significantly reduced weed density in maize and soybean cultures except for one pass of post-emergent harrowing. In maize and soybean respectively, twice hoeing combined with band herbicide application on ridge tops or twice hoeing combined with living mulch in valleys achieved 70 - 100% and 77 - 86% WCE (within inter-row areas) and 66 - 72% and 67 - 79% WCE (within intra-row areas). Post-emergent harrowing treatments on ridge tops performed poorly in maize (46% WCE) and soybean (10% WCE). Therefore, twice hoeing combined with band herbicide application on ridge tops or twice hoeing combined with living mulch in the valley were considered best in selectivity due to higher weed control efficacy (inter – and intra-row), little or no crop damage, and highest grain yield as comparable to broadcast herbicide applications. The fourth article evaluated four autonomous inter and intra-row weeding methods in maize, sunflower, and sugar beet. Within the intra-row area, the treatment involved are; finger weeding, AI-based hoeing actuators, and band herbicide spraying – each simultaneously combined with sensor-guided inter-row hoeing using K.U.L.T iSelect®. In the six experiments conducted, all treatments attained higher yield, with more than 77% reduction in weed density. Most experiments recorded non-significant crop losses. Intra-row band-spraying or AI-based hoeing actuation (combined with inter-row hoeing) achieved 91% and 77% WCE respectively across maize, sugar-beet, and sunflower. However, as an autonomous system, band herbicide treatment was preferable in terms of herbicide savings (60%) and tractor speed comparable to broadcast herbicide application.