Selective herbicides control weeds in cereal crops and break down over time, allowing safe planting of legumes in the following years. However due to climatic inconsistencies and changing farming practices, this is not always the case, and residues can inhibit formation of legume/rhizobia symbioses. The objectives were to determine whether: i) exposure to triasulfuron, even at extremely low levels, reduces shoot and root growth and nodulation of five diverse and widely sown legume pasture cultivars in Australian farming systems; and ii) sowing legumes prior to recommended plant-back criteria being met for chlorsulfuron, triasulfuron herbicide, clopyralid, and pyroxasulfone herbicides results in unacceptable damage to subsequently sown pasture and crop legumes, causing reduced root and shoot growth, nodulation and N fixation. A series of glasshouse and field experiments explored herbicide residue impact on commonly used legumes in dryland farming systems. A glasshouse study determined triasulfuron at concentration 0.000225 g a.i/ha, a (1/100,000) dilution of the label rate caused significant (p < 0.001) decrease in nodule count, root length, root, shoot weight for cv. Bartolo and cv. Dalkeith, and at 0.225 g a.i/ha and 2.25 g a.i/ha for all five cultivars tested. A bioassay assessed cv. Dalkeith health when grown in field soil-cores taken 4, 7 and 10 months after herbicide application (chlorsulfuron, triasulfuron, clopyralid and pyroxasulfone) to a wheat crop. For all three, herbicide residues significantly decreased (p < 0.001) nodule number, shoot weight, root length and whole plant weight of cv. Dalkeith compared to control. A field experiment assessed nodulation of five pasture and two crop legumes sown dry (dormant summer sowing), or following rainfall 10.5 months after initial herbicide application. Nodulation of all legume cultivars decreased in plots treated with clopyralid. Chlorsulfuron decreased nodulation for all cultivars except and . Triasulfuron reduced nodulation for all cultivars except and . Pyroxasulfone decreased nodulation cv. Casbah and cv. Mandalup. Herbicide residues from preceding cereal crops reduced fitness and symbiotically fixed N in subsequently sown pasture or crop legumes Our study highlighted label plant-back recommendations should be strictly adhered to, despite conflict with modern farming approaches of dry or early sowing) to combat climate change. This outcome may consequently lower profitability and increase the carbon footprint of farming systems.

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除草剂残留对旱地农业豆类的不利影响

选择性除草剂可以控制谷类作物中的杂草，并随着时间的推移而分解，从而可以在接下来的几年中安全种植豆类作物。然而，由于气候不一致和耕作方式的变化，情况并非总是如此，残留物会抑制豆科植物/根瘤菌共生体的形成。目标是确定： i) 接触三磺隆，即使在极低的水平下，也会减少澳大利亚农业系统中五种不同且广泛播种的豆科牧草品种的芽和根的生长以及结瘤； ii) 在氯磺隆、三磺隆除草剂、二氯吡啶酸和派罗克磺隆除草剂达到建议的回植标准之前播种豆类，会对随后播种的牧草和豆类作物造成不可接受的损害，导致根和芽生长、结瘤和固氮减少。一系列温室和田间实验探讨了除草剂残留对旱地农业系统中常用豆类的影响。一项温室研究确定三苯磺隆浓度为 0.000225 g ai/ha，标签率的 (1/100,000) 稀释导致 cv 的根瘤数、根长、根、芽重显着 (p < 0.001) 减少。巴托洛和cv。 Dalkeith，所有测试的五个品种的施用量为 0.225 g ai/ha 和 2.25 g ai/ha。生物测定评估了简历。对小麦作物施用除草剂（氯磺隆、三苯磺隆、二氯吡啶酸和吡咯磺隆）后 4、7 和 10 个月采集的田间土芯中生长的 Dalkeith 健康状况。对于这三种情况，除草剂残留显着降低了 cv. 的根瘤数量、芽重、根长和整株重量 (p < 0.001)。达尔基斯与对照相比。一项田间试验评估了五种牧草和两种作物豆类的结瘤情况，这些作物是干播（休眠夏季播种）或初次施用除草剂后 10.5 个月降雨后播种的。在用二氯吡啶酸处理的地块中，所有豆类品种的结瘤均减少。氯磺隆减少了除 和 之外的所有品种的结瘤。除 和 外，三磺隆减少了所有品种的结瘤。 Pyroxasulfone 减少结瘤 cv。卡斯巴和简历。曼达鲁普。先前谷类作物的除草剂残留物降低了随后播种的牧草或豆类作物的适应性，并共生固定了氮。我们的研究强调，尽管与应对气候变化的现代农业方法（干播或早播）相冲突，但仍应严格遵守标签种植建议。这一结果可能会降低农业系统的盈利能力并增加碳足迹。