Recovery of Legumes in Northern Temperate Pastures Following the Application of Broadleaf Herbicides

Résumé du livre

Field and greenhouse trials were conducted to assess the breakdown of soil residues of two broadleaf herbicide bioactives, aminopyralid and aminocyclopyrachlor, as well as associated legume reestablishment/recovery and pasture sward production dynamics. Greenhouse trials indicated legume seedling germination and emergence was unaffected 15 months-after-treatment (MAT), while field trials showed recovery 24 MAT. Short-term variable dose trials suggest that herbicide rates below recommended rates will not allow legume reestablishment during the growing season of application. Herbicide bioactives were functionally indistinguishable, and legume species of interest, alfalfa (Medicago sativa L.) and white clover (Trifolium repens L.), had similar responses to herbicide application. The effects of mowing on legume recovery were dependent on legume identity, with increased density of clover, and neutral effects on alfalfa. Total forage production was unaffected by herbicide application, with increases in biomass noted over the length of the study. Recovery of weedy species (dandelion) was similar to that of legumes, at 22 MAT.