Seedling emergence and biomass data of nine dryland plant species characterizing the impact of soil residual auxin herbicide across two soil types and water pulse events on greenhouse growth; Las Cruces, New Mexico, Spring 2021

Synthetic-auxin herbicides are often used to control woody plants and aid in grassland restoration. Seed-based restoration is common alongside herbicide applications and there may be unintended effects of these herbicides on dryland plant species at the seed and seedling stages. Additionally, abiotic conditions at the time of herbicide application may influence herbicide-soil-plant interactions. We conducted a greenhouse study to examine the effects of a common shrub-control herbicide mix and its interaction with soil type and a post-herbicide water pulse on common desert plant seeds and seedlings. In this greenhouse study, we found that a subset of species responded negatively to soil residual herbicide activity of a mixture of aminopyralid, clopyralid, and triclopyr at the seed and seedling stages. Species sensitive to soil herbicide residues were primarily shrub and forb species that are often the target species of herbicide applications for woody plant control, such as Prosopis glandulosa (honey mesquite) and Larrea tridentata (creosote bush). However, two shrub species (Atriplex canescens [four-wing saltbush] and Yucca elata [soaptree yucca]) and one perennial grass species (Digitaria californica [Arizona cottontop]), which are used in dryland restoration projects, were found to be particularly sensitive to soil residual herbicide activity. Thus, if using these herbicides to control woody plants and restore herbaceous vegetation via active seeding or relying on the in situ seed bank, considerations should be given to what species are used in the seed mix, what species are already present in the soil seed bank, and other details of the circumstances of herbicide application.

合成生长素类除草剂（Synthetic-auxin herbicides）常被用于防控木本植物，辅助草地生态修复。基于种子的生态修复模式常与除草剂施用配套开展，此类除草剂或对旱地植物的种子及幼苗阶段产生非预期影响。此外，除草剂施用时的非生物环境条件，可能影响除草剂-土壤-植物间的相互作用。本研究开展温室试验，以探究一种常用灌木防控除草剂复配剂的效应，及其与土壤类型、除草剂施用后补水脉冲的交互作用对常见荒漠植物种子与幼苗的影响。本温室试验结果显示，部分物种在种子及幼苗阶段，对由氨吡啶酸（aminopyralid）、氯吡酸（clopyralid）与三氯吡氧乙酸（triclopyr）复配而成的除草剂的土壤残留活性产生负向响应。对土壤除草剂残留敏感的物种，多为木本植物防控除草剂的目标物种——灌木与杂类草，例如牧豆树（Prosopis glandulosa, "honey mesquite"）与三齿拉瑞阿（Larrea tridentata, "creosote bush"）。然而，两种应用于旱地修复项目的灌木物种——四翅滨藜（Atriplex canescens, "four-wing saltbush"）与皂树丝兰（Yucca elata, "soaptree yucca"），以及一种多年生禾草亚利桑那绒毛草（Digitaria californica, "Arizona cottontop"），被发现对土壤残留除草剂活性尤为敏感。因此，若使用此类除草剂防控木本植物，并通过人工播种或依赖原位土壤种子库恢复草本植被，需综合考量种子混合料所用物种、土壤种子库中已存在的物种，以及除草剂施用的各类细节条件。