Abstract Weeds are the major pests of forage production in India. An herbicide program is necessary for effective weed control in Egyptian clover (Trifolium alexandrinum L.). The study was conducted in 2013 and 2014 (two years) with an aim to evaluate the response of Egyptian clover and weeds to different herbicides that were being used in various cropping systems in Uttar Pradesh, India. Weed density and biomass, phytotoxicity of herbicides on crop, chlorophyll and carotenoid content in crop samples, root nodulation, soil dehydrogenase activity, soil microbial activity and herbicides effect on dry fodder yield were evaluated. Seventeen (three grasses, and 14 broadleaves) different weed species were observed in this study. Anagallis arvensis L., Cichorium intybus L., Cynodon dactylon (L.) Pers., Dactyloctenium aegyptium (L.) Wild. and Phalaris minor Retz. were the dominant weed species during the crop season. Among herbicides, Alachlor PRE and Imazethapyr PRE decreased grass weeds by 72% and 75% respectively, compared to weedy check, with no injury to crop at 25 days after sowing (DAS). However, alachlor PRE has controlled 64% more broadleaf weeds compared to Imazethapyr. At 50 DAS, imazethapyr POST, alachlor PRE fb quizalofop-ethyl POST provided excellent control of weeds, and resulted in yield equivalent to non-treated weed free check. Further, alachlor (PRE) fb quizalofop-ethyl (POST) and imazethapyr (POST) were selective herbicides on Egyptian clover (very slight to slight injury), recorded greatest nodule number (23–38 plant−1) and soil microbial community compared to other herbicide treatments. For grass weeds, propaquizafop provided effective control but had phytotoxic effect on the crop. In current scenario, where alachlor has been banned, application of either imazethapyr PRE/POST or imazethapyr PRE fb quizalofop-ethyl POST could be the potential herbicide options for control of weeds and obtaining higher yield of Egyptian clover.

中文翻译：

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除草剂对埃及三叶草 (Trifolium alexandrinum L.) 杂草控制、土壤健康参数和产量的影响

摘要 杂草是印度牧草生产的主要害虫。除草剂计划对于有效控制埃及三叶草 (Trifolium alexandrinum L.) 的杂草是必要的。该研究于 2013 年和 2014 年（两年）进行，旨在评估埃及三叶草和杂草对印度北方邦各种种植系统中使用的不同除草剂的反应。评估了杂草密度和生物量、除草剂对作物的植物毒性、作物样品中的叶绿素和类胡萝卜素含量、根瘤形成、土壤脱氢酶活性、土壤微生物活性和除草剂对干饲料产量的影响。在这项研究中观察到 17 种（三种草和 14 种阔叶）不同的杂草种类。Anagallis arvensis L., Cichorium intybus L., Cynodon dactylon (L.) Pers., Dactyloctenium aegyptium (L.) Wild。和法拉里斯小雷兹。是作物季节的主要杂草种类。在除草剂中，与杂草检查相比，甲草胺 PRE 和咪草烟 PRE 分别减少了 72% 和 75% 的杂草，播种后 25 天 (DAS) 对作物没有伤害。然而，与咪草烟相比，甲草胺 PRE 控制了 64% 的阔叶杂草。在 50 DAS 时，咪草烟 POST、甲草胺 PRE fb quizalofop-ethyl POST 提供了出色的杂草控制，并产生了与未处理的无杂草检查相当的产量。此外，甲草胺 (PRE) fb quizalofop-ethyl (POST) 和咪草烟 (POST) 是埃及三叶草的选择性除草剂（非常轻微到轻微的伤害），记录的最大根瘤数（23-38 株植物-1）和土壤微生物群落与其他除草剂处理。对于杂草，propaquizafop 提供了有效的控制，但对作物具有植物毒性作用。在目前禁用甲草胺的情况下，应用咪草烟 PRE/POST 或咪草烟 PRE fb quizalofop-ethyl POST 可能是控制杂草和提高埃及三叶草产量的潜在除草剂选择。