ABSTRACT Introduced aquatic macrophytes can dominate small agricultural waterways in summer and autumn becoming a significant management problem. Excessive growth can clog waterways, causing drainage issues and reducing agricultural productivity while in-stream velocities are reduced and sedimentation increased. Consequently, water managers remove them by mechanical clearance, chemical spray and cutting which can be costly and have negative impacts on in-stream habitat and ecological health. We trialled three tools to reduce macrophytes: hand-weeding, weed mat and artificial shading, at a reach-scale (50 m) and larger-scale (200–400 m). Hand-weeding reduced cover in the short-term, however macrophytes recovered to pre-treatment levels within one season. Weed mat along the banks was effective at reducing emergent macrophytes, particularly Erythranthe guttata (monkey musk) and Nasturtium microphyllum (watercress). Weed mat lasted for several growing seasons and continued to be effective. Shading over the waterway using polythene markedly reduced submerged macrophytes indicating that heavy shading by riparian plantings could reduce submerged macrophytes in the longer-term. These results indicate that in the short-term, weed mat could be used to limit sprawling emergent macrophytes. In the longer-term, weed mat used in conjunction with riparian planting could provide shading so that macrophyte cover in these small waterways could be reduced and controlled.

中文翻译：

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使用手工除草、杂草垫和人工遮荫的试验工具来控制小型农业水道中多种规模的有害大型植物生长

摘要 引入的大型水生植物可以在夏秋季节主导小型农业水道，成为一个重要的管理问题。过度生长会堵塞水道，导致排水问题并降低农业生产力，同时降低河流流速并增加沉积物。因此，水管理人员通过机械清除、化学喷洒和切割来清除它们，这些方法成本高昂，并对河内栖息地和生态健康产生负面影响。我们试用了三种减少大型植物的工具：手工除草、杂草垫和人工遮荫，覆盖范围（50 m）和更大范围（200-400 m）。人工除草在短期内减少了覆盖率，但大型植物在一个季节内恢复到处理前的水平。河岸边的杂草垫可有效减少新出现的大型植物，特别是 Erythranthe guttata（猴麝香）和 Nasturtium microphyllum（豆瓣菜）。杂草垫持续了几个生长季节并继续有效。使用聚乙烯在水道上遮荫可显着减少沉水植物，这表明河岸种植的重度遮荫可以长期减少沉水植物。这些结果表明，在短期内，杂草垫可用于限制蔓延的挺生植物。从长远来看，与河岸种植结合使用的杂草垫可以提供遮荫，从而可以减少和控制这些小水道中的大型植物覆盖。使用聚乙烯在水道上遮荫可显着减少沉水植物，这表明河岸种植的重度遮荫可以长期减少沉水植物。这些结果表明，在短期内，杂草垫可用于限制蔓延的挺生植物。从长远来看，与河岸种植结合使用的杂草垫可以提供遮荫，从而可以减少和控制这些小水道中的大型植物覆盖。使用聚乙烯在水道上遮荫可显着减少沉水植物，这表明河岸种植的重度遮荫可以长期减少沉水植物。这些结果表明，在短期内，杂草垫可用于限制蔓延的挺生植物。从长远来看，与河岸种植结合使用的杂草垫可以提供遮荫，从而可以减少和控制这些小水道中的大型植物覆盖。