Pyone Win Win, Bell Richard W, Rose Michael T, McGrath Gavan S
SoilsWest, Center for Sustainable Farming Systems, Food Futures Institute, Murdoch University, Australia.
Cooperative Research Centre for High Performance Soils, Callaghan, New South Wales, Australia.
PLoS One. 2025 Aug 21;20(8):e0330225. doi: 10.1371/journal.pone.0330225. eCollection 2025.
Herbicide residues in soil from previous crops or from pre-emergent treatments can have unintended toxicity on the next crop. Despite this there is limited published information on toxicity thresholds for many crops or herbicides. This study aimed to quantify shoot and root responses of six common winter grains crops (canola, chickpea, fieldpea, lentil, lupin and wheat) to increasing concentration of four common herbicides (clopyralid, pyroxasulfone, propyzamide and trifluralin) in soil. Lentil emergence was highly sensitive to clopyralid (29 μg kg-1 for a 50% reduction, ED50) while wheat emergence was sensitive to propyzamide and trifluralin, with complete inhibition at 100 μg kg-1 and 375 μg kg-1, respectively. Shoot and root parameters of the legumes, except lupin, were significantly reduced by clopyralid, with ED50 values ranging between 3-27 μg kg-1. Canola was sensitive to pyroxasulfone, with shoot and root biomass ED50 at 21 and 8 μg kg-1, respectively. Pyroxasulfone also severely reduced root length of all tested crops (ED50 values 6-53 μg kg-1). Root and shoot growth in wheat was most susceptible to propyzamide followed by trifluralin. This study found that one or more herbicides had the potential to cause significant phytotoxic effects in all crops at concentrations below recommended application rates and below those detected in a recent field survey of pre-sowing herbicide residues in field soils around Australia. These results suggest the risk of early crop damage residual herbicides in very light-textured soils. More effort is now required to determine potential effects on different soil types and crop yields, to enable better spatial and economic risk assessment.
前茬作物土壤中或苗前处理残留的除草剂可能会对下茬作物产生意外的毒性。尽管如此，关于许多作物或除草剂毒性阈值的公开信息仍然有限。本研究旨在量化六种常见冬季谷类作物（油菜、鹰嘴豆、豌豆、小扁豆、羽扇豆和小麦）对土壤中四种常见除草剂（氯吡嘧磺隆、唑啉草酯、敌稗和氟乐灵）浓度增加的地上部和根部反应。小扁豆出苗对氯吡嘧磺隆高度敏感（50%降低时的浓度为29μg kg-1，即半数有效剂量），而小麦出苗对敌稗和氟乐灵敏感，在100μg kg-1和375μg kg-1时分别完全抑制。除羽扇豆外，氯吡嘧磺隆显著降低了豆类作物的地上部和根部参数，半数有效剂量值在3-27μg kg-1之间。油菜对唑啉草酯敏感，地上部和根部生物量的半数有效剂量分别为21μg kg-1和8μg kg-1。唑啉草酯还严重降低了所有受试作物的根长（半数有效剂量值为6-53μg kg-1）。小麦的根和地上部生长对敌稗最敏感，其次是氟乐灵。本研究发现，一种或多种除草剂在低于推荐施用量且低于澳大利亚近期对田间土壤播前除草剂残留进行的田间调查中检测到的浓度时，就有可能对所有作物造成显著的植物毒性影响。这些结果表明，在质地非常轻的土壤中，残留除草剂有造成早期作物损害的风险。现在需要做出更多努力来确定对不同土壤类型和作物产量的潜在影响，以便进行更好的空间和经济风险评估。
