Weed control in medicinal and aromatic plants (MAP) is particularly challenging as many species have a low competitiveness at early growth stages. Intra-row (within the row) mechanical weed control is most challenging since crops may be damaged as well. Here we compared five different devices for mechanical intra-row weeding (finger, torsion and rotative weeders, tine harrow, ridger share) in lemon balm and parsley, focusing on the critical stage of crop establishment. In total, eight field trials were carried out in 2020 and 2021 at two experimental farms of the University Bonn in the west of Germany. The devices were tested in replicated trials after optimising the settings on test plots. Data on weed control efficacy (WCE) and crop damage were analysed with ANOVA. The average WCE was 66 % and had a high variability ranging from 0 % to 100 %. Tine harrows could be applied most often and at earlier growth stages, followed by finger weeder. Highest crop damage was noted after use of rotative weeder. Yield decreasing effects were only significant in two cases and tended to be lower in transplanted than in sown lemon balm and parsley. However, due to variable operating conditions a consistent ranking of weeding devices was not possible. We conclude that despite significant technical progress during the last two decades, a complete replacement of herbicides is difficult at present, unless weed control is carried out manually. Further research is needed to ascertain under which environmental and management conditions mechanical intra-row weeding is most effective in the field, and how these techniques can be best integrated with other weed control methods.

In the Mediterranean area, vineyard soils are often characterized by a high stone content. In these contexts, where tools commonly adopted for under-row weed control are frequently damaged, the utilization of a chain mower could be a preferable alternative. This research aims to compare a modified mower with chains with other tools commonly employed that control weeds through tillage, such as motorized discs, blade weeder, and rotary star hoe. Weed control effectiveness, effects on weed flora composition, soil compaction, and operative efficiencies were evaluated. The chain mower allowed us to obtain encouraging results of weed biomass reduction (55.4 and 25.4%, between and around vine trunks, respectively), weed height reduction (35.9%), and weed cover reduction (79.2%), comparable to the other tools. All the tools showed a lower weed control efficacy around vine trunks rather than between them (weed biomass reductions of 24.8% and 52.6%, respectively). Results regarding the effect on weed flora composition seem to confirm this trend. Despite the higher chain mower field time (3.78 h ha-1) and fuel consumption (24.24 kg ha-1) compared to the blade weeder and the rotary star hoe, its versatility in stony soil and its lower impact on soil (soil penetration resistances of 1602.42 and 2262.83 kPa in 2022 and 2023, respectively) compared to the other tools make it a potentially advantageous implement for under-row weed management in vineyards. Further studies could be useful to improve chain mower performance, particularly around vine trunks, by evaluating in different planting layouts different dimensions of both the cutting element and feeler, which allows the vine-skipping mechanism.