Camera-guided Weed Hoeing in Winter Cereals with Narrow Row Distance

Roland Gerhards,David Reiser,Benjamin Kollenda,Kurt Möller,Andreas Butz,Jannis Machleb,Hans-Werner Griegentrog

doi:10.1007/s10343-020-00523-5

Roland Gerhards, David Reiser + Show 5 more

Open Access

https://doi.org/10.1007/s10343-020-00523-5

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Abstract

Farmers are facing severe problems with weed competition in cereal crops. Grass-weeds and perennial weed species became more abundant in Europe mainly due to high percentages of cereal crops in cropping systems and reduced tillage practices combined with continuous applications of herbicides with the same mode of action. Several weed populations have evolved resistance to herbicides. Precision weed hoeing may help to overcome these problems. So far, weed hoeing in cereals was restricted to cropping practices with row distances of more than 200 mm. Hoeing in cereals with conventional row distances of 125–170 mm requires the development of automatic steering systems. The objective of this project was to develop a new automatic guidance system for inter-row hoeing using camera-based row detection and automatic side-shift control. Six field studies were conducted in winter wheat to investigate accuracy, weed control efficacy and crop yields of this new hoeing technology.A three-meter prototype and a 6-meter segmented hoe were built and tested at three different speeds in 150 mm seeded winter wheat. The maximum lateral offset from the row center was 22.53 mm for the 3 m wide hoe and 18.42 mm for the 6 m wide hoe. Camera-guided hoeing resulted in 72–96% inter-row and 21–91% intra-row weed control efficacy (WCE). Weed control was 7–15% higher at 8 km h−1 compared to 4 km h−1. WCE could be increased by 14–22% when hoeing was combined with weed harrowing. Grain yields after camera-guided hoeing at 8 km h−1 were 15–76% higher than the untreated control plots and amounted the same level as the weed-free herbicide plots. The study characterizes camera-guided hoeing in cereals as a robust and effective method of weed control.

Highlights

Camera-guided hoeing technologies with automatic sideshift control have significantly improved mechanical weed control in crops with row distances higher than 180 mm such as maize, sugar beet, soybean, sunflower and some vegetables (Tillett and Haugue 1999; Tillet et al 2002; Griepentrog et al 2007; Kunz et al 2015, 2018)
For crop row distance of 150 mm, both hoes with automatic side-shift control guided the hoeing blades precisely in the center between the crop rows until cereals had developed 5 tillers
The new camera-guidance system allowed selective interrow weed hoeing in cereals with narrow row distances of 150 mm

Summary

Introduction

Camera-guided hoeing technologies with automatic sideshift control have significantly improved mechanical weed control in crops with row distances higher than 180 mm such as maize, sugar beet, soybean, sunflower and some vegetables (Tillett and Haugue 1999; Tillet et al 2002; Griepentrog et al 2007; Kunz et al 2015, 2018). In addition to that, weed competition was higher at wider row distances (Blair et al 1997) compared to conventional row distances of 125–150 mm (Rasmussen and Svenningsen 1995; Hammarström et al 1993) This is probably a consequence of lower competitive ability of the crop in early growth stages and later canopy closure at wide row spacing

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