Weed competition severely constrains cassava root yield in sub-Saharan Africa; thus, good weed control measures, including the use of herbicides, are increasingly important. Herbicide trials were conducted at five locations across eastern, western, and north-central Nigeria over two cropping seasons (2014 and 2015). Nineteen premixed PRE herbicides applied at different rates were evaluated for efficacy on weeds and selectivity on cassava. Manual hoe-weeding at 4, 8, and 12 wk after planting (WAP) and two S-metolachlor + atrazine treatments commonly used by cassava growers were included for comparison. Six of the 19 PRE herbicide treatments (indaziflam + isoxaflutole, indaziflam + metribuzin, flumioxazin + pyroxasulfone, isoxaflutole, acetochlor + atrazine + terbuthylazine, and terbuthylazine + S-metolachlor) consistently provided 80% to 98% broadleaf and grass weed control up to 8 wk after treatment. Overall, PRE herbicide treatments and cassava yield were significantly positively correlated. Herbicide treatments terbuthylazine + S-metolachlor, flumioxazin + pyroxasulfone, diflufenican + flufenacet + flurtamone (respectively, 60 + 60 + 60, 120 + 120 + 120, 90 + 360 + 120, and 135 + 360 + 180 g ha−1), acetochlor + atrazine + terbuthylazine (875 + 875 + 875 g ha−1), S-metolachlor + atrazine (870 + 1,110 g ha−1), oxyfluorfen (240 g ha−1), indaziflam + isoxaflutole (75 + 225 g ha−1), indaziflam + metribuzin (75 + 960 g ha−1), and aclonifen + isoxaflutole (500 + 75 g ha−1) contributed to yields exceeding twice the Nigerian national average of 8.76 tonnes ha−1. These treatments had root yields of 1.4 to 2 times higher than plots that had been hoe-weeded three times. There were some adverse herbicide treatment effects such as delayed cassava sprouting and temporary leaf bleaching observed in indaziflam and diflufenican + flufenacet + flurtamone treatments, whereas sulfentrazone caused prolonged leaf crinkling. The PRE applications alone at rates safe for cassava did not provide adequate season-long weed control; supplemental POST weed control is needed about 10 WAP for satisfactory season-long control.

中文翻译：

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筛选用于木薯杂草控制的芽前除草剂

杂草竞争严重限制了撒哈拉以南非洲的木薯根产量；因此，良好的杂草控制措施，包括使用除草剂，变得越来越重要。在两个种植季节（2014 年和 2015 年）期间，在尼日利亚东部、西部和中北部的五个地点进行了除草剂试验。评估了以不同比率施用的 19 种预混 PRE 除草剂对杂草的功效和对木薯的选择性。种植后 4、8 和 12 周手动锄草 (WAP) 和 2小号包括木薯种植者常用的异丙甲草胺 + 阿特拉津处理方法进行比较。19 种 PRE 除草剂处理中的 6 种（吲唑菌胺 + 异恶唑啉、吲唑菌胺 + 灭草灵、氟噻嗪 + 吡唑嘧啶、异恶唑草胺、乙草胺 + 阿特拉津 + 特丁嗪和特丁嗪 +小号-metolachlor) 在处理后 8 周内始终提供 80% 至 98% 的阔叶和禾本科杂草控制。总体而言，PRE除草剂处理与木薯产量呈显着正相关。除草剂处理特丁嗪 +小号-异丙甲草胺、氟米沙嗪 + 吡咯唑啉、敌氟尼康 + 氟灭草胺 + 氟他酮（分别为 60 + 60 + 60、120 + 120 + 120、90 + 360 + 120 和 135 + 360 + 180 g ha-1), 乙草胺 + 阿特拉津 + 特丁嗪 (875 + 875 + 875 g ha-1),小号-异丙甲草胺 + 阿特拉津 (870 + 1,110 g ha-1), 乙氧氟草醚 (240 g ha-1), 吲达唑仑 + 异恶唑草胺 (75 + 225 g ha-1), 吲唑菌灵 + metribuzin (75 + 960 g ha-1), 和 aclonifen + isoxaflutole (500 + 75 g ha-1) 的产量超过尼日利亚全国平均水平 8.76 吨公顷的两倍-1. 这些处理的根产量比锄草 3 次的地块高 1.4 至 2 倍。吲哒唑菌素和氟苯尼康+氟灭草胺+氟他酮处理中观察到木薯发芽延迟和叶片暂时漂白等一些不良除草剂处理效果，而磺胺嘧啶则导致叶片长时间起皱。仅以对木薯安全的速度施用 PRE 并不能提供足够的全季杂草控制；需要大约 10 WAP 的补充 POST 杂草控制才能获得满意的全季控制。