Research and development activities on non‐chemical weed control methods to date have mainly focused on mechanical and thermal applications. Selectivity in mechanical weed control is obtained using dynamically actuated harrows. Selectivity in thermal weed control is obtained through a certain heat tolerance of the crop. In conservation agriculture (CA), weed emergence is partially suppressed by constant soil cover with crops or cover crops. Large amounts of plant residues therefore remain on the soil, which make mechanical methods inefficient or difficult to implement. And thermal methods need to prevent not only crop damage but also fire from situationally dry plant residues. In this review, technologies that can potentially be used for in‐crop weed control in CA are discussed. The technologies reviewed include spot‐flaming, electric resistance heating, electromagnetic irradiation and steam/hot water application. Their evaluation focuses on efficiency and specificity (spatial precision). This review indicates that existing equipment does not fulfil the spatial precision required in CA and that further research and development is required on this topic. In particular, the authors suggest further research on the use of laser diodes, micro‐flames and capacitive coupling of electric fields. It seems that the use of automated imaging systems for weed/crop differentiation is a prerequisite in CA to enable automatisation of weed control.

中文翻译：

---

保护性农业热杂草控制技术——综述

迄今为止，非化学杂草控制方法的研究和开发活动主要集中在机械和热应用上。机械杂草控制的选择性是使用动态驱动的耙获得的。热杂草控制的选择性是通过作物的一定耐热性获得的。在保护性农业 (CA) 中，作物或覆盖作物的持续土壤覆盖部分抑制了杂草的出现。因此，大量植物残留物留在土壤上，这使得机械方法效率低下或难以实施。热方法不仅需要防止作物受损，还需要防止因干燥的植物残留物引起火灾。在这篇综述中，讨论了可能用于 CA 作物间杂草控制的技术。审查的技术包括点燃烧、电阻加热、电磁辐射和蒸汽/热水应用。他们的评估侧重于效率和特异性（空间精度）。该审查表明，现有设备不能满足 CA 要求的空间精度，需要在该主题上进一步研究和开发。作者特别建议进一步研究激光二极管的使用、微火焰和电场的电容耦合。似乎使用自动化成像系统进行杂草/作物区分是 CA 实现杂草控制自动化的先决条件。该审查表明，现有设备不能满足 CA 要求的空间精度，需要在该主题上进一步研究和开发。作者特别建议进一步研究激光二极管的使用、微火焰和电场的电容耦合。似乎使用自动化成像系统进行杂草/作物区分是 CA 实现杂草控制自动化的先决条件。该审查表明，现有设备不能满足 CA 要求的空间精度，需要在该主题上进一步研究和开发。作者特别建议进一步研究激光二极管的使用、微火焰和电场的电容耦合。似乎使用自动化成像系统进行杂草/作物区分是 CA 实现杂草控制自动化的先决条件。